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1. Atkinson-Willes, G. 1969. Wildfowl and recreation: a balance of requirements. British Water Supply 11:5-15.

The author accepts human disturbance to waterfowl as a given and proposes that compromises be worked out among water-based recreation interests to provide for the important role that Britain plays as wintering habitat for European waterfowl. Suggestions are given for consideration of the needs of waterfowl in working out these compromises. Sailing, canoeing, rowing, water-skiing, speed-boating, hydroplaning, fishing, bird-watching, picnicking, and shooting are considered as to how they affect waterfowl and how resource use might be partitioned. There is no literature cited section.

2. Austin, J. E. 1988. Winter ecology of Canada geese in northcentral Missouri. Ph.D. thesis, University Missouri, Columbia. 284 pp.

Canada geese (Branta canadensis) tended to spend more time alert in agricultural habitats, which were probably more exposed to disturbances than seasonal wetlands in the refuge interior or the water roost sites. Vigilance did not differ among the habitats in the hunting season), thus the effects of hunting disturbances are far-reaching. All wetland use in late fall occurred in the refuge interior, which is not hunted. However, geese in the refuge interior often responded to gunshots from the hunting zone by ceasing other activities and becoming alert or vigilant at least briefly. Canada Geese may habituate to disturbances in some locations, which may account for the lower vigilance of geese on pastures in winter. These pastures appeared to be traditionally used by geese and may be considered as safe fields. Geese appeared to avoid or leave locations where excessive disturbances in an area restricted feeding and where geese did not habituate to the disturbances.

3. Balát, F. 1969. Influence of repeated disturbance on the breeding success in the mallard, Anas platyrhynchos Linn. Zoologicke Listy 18:247-252.

In a regularly flooded bottomland forest, some 10 ha in size, 98 nests of the mallard were found and regularly inspected. They were situated on pollarded willows (Salix spp.). After their first arousal from their nests, the mallard became much more sensitive to approaching man. Water bodies inside that forest are visited by sports anglers who stay there from early morning till dusk on days of rest. The mallard aroused by them cannot return to their nests for several days. This fact resulted in 56 (or 57.2%) abandoned clutches, including those shortly before hatching and, in three cases, even hatching young. On the contrary, breeding was not disturbed in places (even very frequented) where the incubating females were not roused by the inspection.

4. Barngrover, L. 1974. W. E. Kirch Wildlife Management Area resource inventory and long range plan summary. Nevada Department of Fish and Game. 12 pp.

In the late 1950's the Nevada Fish and Game Commission recognized the wildlife values of what is now the Kirch Wildlife Management Area. The area was purchased in April 1959 with Pittman-Robertson funds primarily for waterfowl, with secondary considerations to be given to fish and other wildlife species. Fishing is the most popular activity on the management area in terms of public use days. A conflict apparently exists between public fishing interests and waterfowl production from prime waterfowl habitat. Modification of future fishing regulations would then depend upon maximum assurance that high waterfowl production from prime waterfowl habitat would continue.

5. Bartelt, G. A. 1987. Effects of disturbance and hunting on the behavior of Canada goose family groups in eastcentral Wisconsin. Journal of Wildlife Management 51:517-522.

Disturbances on roosting areas resulted in increased separation of family members of Canada geese in 1979 may have contributed to the large number of family members shot that year. The cohesiveness of family groups was affected after a family member was shot. Family (after hunting losses) and random groups used the same roosting areas less as the season advanced. Intact family groups used the same roosting areas at the same rate throughout the season. A disintegration of family structure appears to be related to the extent of disturbance and hunting pressure present during the years of this study.

6. Batten, L. A. 1977. Sailing on reservoirs and its effects on water birds. Biological Conservation 11:49-58.

Mallard (Anas platyrhynchos), tufted duck (Aythya fuligula), and common pochard (Aythya ferina) still use the Brent reservoir in autumn and winter despite intensified sailing activities because part of the reservoir which is shallow and marshy is not accessible to boats. During the autumn of 1975 Canadian pondweed (Elodea canadensis) choked the northern arm and boating had to be suspended after August, resulting in a build-up of 159 common pochards, 30 tufted ducks, 17 northern shovelers (Anas clypeata), and 12 gadwalls (Anas strepera). Distances at which flocks of ducks would move from an oncoming sailing dinghy were estimated for tufted duck at 275 m and common pochard at 450 m, and small groups of smew (Mergellus albellus) to within 100 m. Mallard (Anas platyrhynchos) were similar to smew. Green-winged teal (Anas crecca), Eurasian wigeon (Anas penelope), and northern shoveler are more sensitive than mallard by an unknown amount. Green-winged teal and Eurasian wigeon have already stopped using the reservoir due to sailing activities. Perhaps screening vegetation on reservoir banks and provision of large floating vegetated rafts would reduce disturbance.

7. Beard, E. R. 1953. The importance of beaver in waterfowl management at the Seney National Wildlife Refuge. Journal of Wildlife Management 17:398-436.

If certain areas are opened to the public for recreational use, such as fishing, use by waterfowl will sharply decrease. as demonstrated in 1947 when Study Area IV was included within the area open to fishing. During that year only two broods and 70 adult ducks were seen. In the two years that followed, however, when this marsh was closed to fishing, a marked increase in both broods and adults was noticed. Study Area IV has the highest interspersion index (45/9) and was foremost in duckling production in 1948 and 1949. By contrast its 1947 output was very low because that year it was included within the open-to-fishing zone. Because of the constant disturbance from fishermen, was virtually abandoned as a duckling-rearing marsh.

8. Bélanger, L., and J. Bédard. 1989. Responses of staging snow geese to human disturbance. Journal of Wildlife Management 53:713-719.

Authors studied the effects of human disturbance on staging in snow geese (Chen caerulescens atlantica) spring and fall in the Montmagny bird sanctuary, Québec, 1985-87. They recorded 652 disturbances (any event causing all or a part of the snow goose flock to take flight) in 471 hr of observation. Rate of disturbance was higher in fall (1.46/hr) than in spring (1.02/hr) (P < 0.001). The entire flock was disturbed in 20% of all cases. Mean time in flight was 56 and 76 sec in fall and spring (P = 0.049). Transport-related activities, particularly low-flying aircraft, caused > 45% of all disturbances in spring and fall. In 40% of all cases (P > 0.05) snow geese stopped feeding following a disturbance. Mean time to resume feeding was 726 sec in fall compared to 122 sec in spring (P < 0.001). Disturbance level on a fall day was related to snow goose use the following day (P < 0.01). When disturbance exceeded 2.0/hr, 50% fewer snow geese were present the next day. Low-level aircraft flights over goose sanctuaries should be strictly regulated.

9. Bélanger, L., and J. Bédard. 1990. Energetic cost of man-induced disturbance to staging snow geese (Chen caerulescens atlantica). Journal of Wildlife Management 54:36-41.

Energetic cost of man-induced disturbance to fall-staging snow geese in Québec was estimated. Two responses of birds to disturbance were considered: (1) birds fly away but promptly resume feeding following a disturbance (Response A), and (2) birds interrupt feeding altogether (Response B). Daylight foraging time decreased by 4% to 51% depending on disturbance levels. Average rate of disturbance (1.46/hr) in Response A resulted in a 5.3% increase in hourly energy expenditure (HEE) combined with a 1.6% reduction of hourly metabolizable energy intake (HMEI). In Response B, HEE increased by 3.4% and HMEI decreased by 2.9% to 19.4%. A 4% increase in night feeding could compensate for energy losses caused solely by disturbance flights (Response A), but a 32% increase in nighttime feeding was required to restore energy losses incurred in Response B. No increase in daily feeding rate was observed between days with different disturbance levels (P > 0.05). Authors concluded that man-induced disturbance had significant energetic consequences for fall-staging greater snow geese.

10. Bell, D. V., and L. W. Austin. 1985. The game-fishing season and its effects on overwintering wildfowl. Biological Conservation 33:65-80.

The trend in Great Britain towards extending the game-fishing season may lead to increased encounters between anglers and overwintering wildfowl. This paper considers the effects on wildfowl due to the start of angling activity in March at Llandegfedd Reservoir. The reservoir is large, but anglers and waterfowl exploit the same restricted areas. Eurasian wigeon (Anas penelope), green-winged teal (Anas crecca), common pochard (Aythya ferina) and mallard (Anas platyrhynchos) were all driven from their preferred feeding or roosting sites and departed from the reservoir prematurely. Temporary reserve areas are suggested at Llandegfedd Reservoir for wildfowl at the start of the fishing season. The correlation coefficient between waterfowl numbers and availability of open grassland in each area shows the effect of angling in the following tabulation:

Species	Before angling activity	After angling activity
Wigeon	0.729*	0.038
Teal	0.784*	-0.034
Pochard	0.601*	-0.138
*Significant at 5% level (df = 11).

11. Bennett, L. J. 1938. The blue-winged teal, its ecology and management. Collegiate Press, Inc., Ames, Iowa. 144 pp.

It was found at the beginning of the nest studies that freshly made paths, trampled grass and weeds, film wrappings, nest markers and other disturbances in the immediate vicinity of a nest were very likely to attract predators. Two blue-winged teal nests (0.8%) were known to have been abandoned because of poor study technique during the early stages of work.

12. Berger, T. R. 1977. The Berger report: northern frontier, northern homeland. Living Wilderness 41:4-33.

During their stay on the staging grounds, snow geese (Chen caerulescens) are highly sensitive to human presence, noise, and aircraft. Dr. William Gunn described experiments where snow geese would not feed any closer than 1.5 mi (2.41 km) from a device simulating noise made by a compressor station, and birds flying over it diverted their course by 90 degrees or more. Snow geese show evidence of being disturbed by an aircraft by flushing at a mean distance of 1.6 mi (2.57 km) from small aircraft, 2.5 mi (4.02 km) from large aircraft, and 2.3 mi (3.70 km) from small helicopters. They also flushed in response to aircraft flying at altitudes of 8,000 to 10,000 ft (2,440 to 3,050 m), the maximum height at which the test flights were conducted. Deliberate harassing of flocks of snow geese in an area approximately 5 mi by 10 mi (8.05 km by 16.09 km) cleared them out of the area in 15 min. Jerald Jacobson inferred that snow geese may avoid an area as large as 20 mi² (32.18 km²) around an operating drill rig, 28 mi² (45.05 km²) around an operating compressor station, and 250 mi² (402.25 km²) around an airstrip during takeoff and landing of aircraft.

13. Bergman, R. D. 1973. Use of southern boreal lakes by postbreeding canvasbacks and redheads. Journal of Wildlife Management 37:160-170.

Human disturbance of summer-molting ducks may adversely influence their selection of molting lakes. Disturbance by humans on Swan Lake was negligible and canvasbacks (Aythya valisineria) were widely distributed on the lake in summer. Dauphin Lake, however, was actively used for recreation by boaters and fishermen and only a few hundred canvasbacks passed their flightless stage at Dauphin Lake well out in the lake far from the nearest food plants and intense boating activity. During fall, thousands of flying canvasbacks readily used the pond-weed-rich southern end of the lake where few ducks were seen in summer. Human activity in this region was no doubt less frequent during fall than summer, but canvasbacks with the power of flight may be more tolerant of disturbance. Similar circumstances could account for the paucity of summer-molting redheads (Aythya americana) at Sagemace Bay even though redheads intensively used nearby Long Island Bay. Sagemace Bay was proximal to the towns of Winnipegosis and Camperville and two roads paralleling the west and southwest shores, while Long Island Bay was relatively secluded.

14. Berry, J. 1939. International wildfowl inquiry, Vol. II, The status and distribution of wild geese and wild duck in Scotland. Cambridge Press. 190 pp.

The disappearance of greylag geese (Anser anser) from Scotland is attributed to excessive disturbance from continual shooting, an aerial bombing range, increasing motor traffic and summer trout fishing in lakes previously undisturbed, egg destruction by farmers who do not want greylag geese in their oat fields, the demand for eggs by collectors who offer the hill shepherds good sums for nests, and disturbance by aircraft. The book has sections on greater white-fronted geese (Anser albifrons), bean geese (Anser fabalis), pink-footed geese (Anser brachyrhynchus), snow goose (Chen caerulescens), brant (Branta bernicla), and Canada geese (Branta canadensis). Section II of the book covers 21 species of ducks. The summary for ducks covers natural enemies (crows, gulls, swans, rats, stoats, angler fish, and pike); destruction caused by man (oil pollution, stake-netting for fish, flight-netting, egg-taking, and excessive shooting); results of increasing traffic (road traffic, boats and shipping, and airplanes); and changes in available food supplies (agriculture, natural feeding, drainage and afforestation, and effects of climate).

15. Berry, R. F. 1988. Disturbance to tundra swans by barge and boat traffic. Loon 60:92.

Approximately 750 tundra swans (Cygnus columbianus) resting on the Wisconsin side of Pool 5 in the Spring Lake area of the Mississippi River left the water surface and departed the area in a downstream direction due to the upstream passage of a tow [barge]. In another instance, approximately 2,500 tundra swans located in the Weaver Bottoms between Swan and Mallard Islands and Minnesota 14 were disturbed by two small boats; all birds observable left the Weaver Bottoms, formed into V's and departed downstream.

16. Bishop, R. A., and R. Barratt. 1970. Use of artificial nest baskets by mallards. Journal of Wildlife Management 34:734-738.

Nest abandonment was responsible for most mallard (Anas platyrhynchos) nest losses in this study. Disturbance by observers was believed to be partly responsible for the abandoned nests.

17. Blokpoel, H., and D. R. M. Hatch. 1976. Snow geese, disturbed by aircraft, crash into power lines. Canadian Field-Naturalist 90:195.

On 8 May 1974 several thousand snow geese (Chen caerulescens) were feeding on a stubble field near Pilot Mound, about 145 km southwest of Winnipeg. The birds covered almost the whole field and some were feeding very close to a power line that bordered one side of the field. A light aircraft flying at an estimated height of 100 to 200 ft (30 to 60 m) approached the field and caused panic among the snow geese. They took wing and in a chaotic mass rushed off the field on the side of the transmission lines. Many geese were injured or killed because they struck the wires, with the total number of birds involved varying from 25 to 75 depending on the person reporting the incident. Several reports of snow goose disturbance in southern Manitoba by light aircraft have been reported, some of which probably involved curious and ill-informed pilots but on other occasions, deliberate harassment.

18. Boag, D. A., and V. Lewin. 1980. Effectiveness of three waterfowl deterrents on natural and polluted ponds. Journal of Wildlife Management 44:145-154.

In 1975, three types of waterfowl deterrent (a model falcon, a moving series of reflectors suspended from a frame, and a human effigy) mounted on floats, were tested for efficacy in deterring waterfowl from entering a series of small natural ponds in the boreal forest of Alberta. Only the effigy appeared to be effective; diving ducks of the genus Aythya were affected most. In 1976, the human effigy was tested on an artificial tailings pond that received aqueous and bituminous effluent from an oil sands extraction plant near Fort McMurray, Alberta. Twenty-seven effigies were deployed over the 150-ha pond. Their effectiveness was judged by comparing the number of waterfowl dying in and associated with this pond in 1975 (without deterrents) with number dying in and associated with it in 1976 (with deterrents). Kill figures in 1976 were significantly lower than expected on the basis of relative abundance of birds in the 2 years. It was assumed that this decline was due to the presence of the effigies.

19. Boldreghini, P., L. Casini, and R. Tinarelli. 1988. Lo svernamento delle Oche nell'area delle Valli di Comacchio (The wintering of geese in the Comacchio area [Po Delta, Northern Adriatic]). Supplemento alle Ricerche di Biologia della Selvaggini 14:51-76.

A comparative analysis of regularly or occasionally frequented sites by bean geese (Anser fabilis), greater white-fronted geese (Anser albifrons), greylag geese (Anser), red-breasted goose (Branta ruficollis), and barnacle geese (Branta leucopsis) showed that shooting pressure was the main factor affecting goose use.

20. Bordignon, L. 1985. Effetti del disturbo antropico su una popolazione di germano reale Anas platyrhynchos. (Effects of human disturbance on a population of mallard Anas platyrhynchos). Avocetta 9:87-88.

Mallards colonizing an artificial lake (0.47 km²) in northwestern Italy were censused from the 1977, when the lake was filled, to 1984. After 1980 the population was severely reduced as a result of disturbance by from 30 to 200 anglers each day on the shores).

21. Bossenmaier, E. F., and W. H. Marshall. 1958. Field-feeding by waterfowl in southwestern Manitoba. Wildlife Monograph 1, The Wildlife Society, Washington, D.C. 32 pp.

Hunting created disturbances on both lake and upland feeding sites. Field-feeding mallard (Anas platyrhynchos) and northern pintail (Anas acuta) flocks were dispersed from the easily reached shores, and gathered in less accessible regions in the northeastern and southwestern portions of the lake. Since hunting from boats was banned these loafing concentrations were rarely disturbed. Well-defined goose flight lines formed during both autumns but usually dispersed after a few days, probably because of hunting pressure on the fields. Geese also preferred the fields near the lake but unlike ducks that were easily forced further away, constantly used them from their arrival until freeze-up almost regardless of weather or shooting. Disturbances by humans on the lake or on fields could not be definitely correlated with variation in flight schedules. However, Girard (1941) in Montana, Pitman (1947) in the British Isles, and Bellrose (1944) in Illinois claim that disturbances, chiefly hunting, caused changes to routines that permitted more peaceful feeding. Hunting pressure at Whitewater Lake may have been too low to influence feeding schedules significantly.

22. Bouffard, S. H. 1982. Wildlife values versus human recreation: Ruby Lake National Wildlife Refuge. Transactions of the North American Wildlife Natural Resources Conference 47:553-558.

This paper summarizes the controversy over conflicts between human recreation and wildlife production at Ruby Lake NWR in Nevada, based chiefly on U.S. Fish and Wildlife Service (FWS) documents and refuge records. The author provides information on the court case arising from a 1978 suit by Defenders of Wildlife. In its decision, the U.S. District Court, District of Columbia (1978:10, quoted from page 556), stated the following: "Neither poor administration of the refuge in the past, nor prior interferences with its primary purposes, nor past recreational uses, nor deterioration of its wildlife resource since its establishment, nor administrative custom nor tradition alters the statutory standard. The Refuge Recreation Act permits recreational use only when it will not interfere with the primary purpose for which the refuge 'was established.' The prior operation of the refuge in a manner inconsistent with that purpose does not change the base point for applying the statute's standard." The first test of the Refuge Recreation Act (1962) set some important precedents for lands managed for wildlife by the FWS. The act and court decision provided strong protection for wildlife from incompatible recreational pressures on NWR's.

23. Bouffard, S. H. 1983. Redhead egg parasitism of canvasback nests. Journal of Wildlife Management 47:213-216.

Nest failure of canvasback ducks (Aythya valisineria) was due mostly to human disturbance and cold weather during 1980 rather than to egg parasitism by redhead ducks (Aythya americana). However, some nest failures were caused by nest desertion immediately after a visit to the nest.

24. Bourget, A. A. 1970. Interrelationships of eiders, herring gulls, and black-backed gulls nesting in mixed colonies in Penobscot Bay, Maine. Masters of Science thesis, University Maine, Orono. 121 pp.

When Bourget's results are compared with those of Choate (1966) and Clark (1968), the higher nesting success in 1969 was caused by two things. First, in Bourget's study 54% of nests were in the open, with 46% located under nesting shelters which afforded better protection against avian predators. Secondly, human interference in the 1969 study did not involve long periods of disturbance while searching for nests, as performed by Choate and Clark. The present research primarily involved observations from a blind which resulted in much shorter periods of disturbance to the colony. During this study, the observer's interference affected the breeding chronology of herring gulls (Larus argentatus), great black-backed gulls (Larus marinus), and common eider (Somateria mollissima). As a result of human disturbance the breeding cycles of the species concerned were delayed especially on the two major islands. It is probable that human disturbance, gull populations, gull species composition, and nesting cover have much more influence on common eider nesting success than eider nesting density on a given island.

25. Brakhage, G. K. 1965. Biology and behavior of tub-nesting Canada geese. Journal of Wildlife Management 29:751-771.

Desertions caused by human activities can be a problem in heavily populated areas, but at Trimble this loss was held to a minimum by regulating opening dates of fishing season and by closing nesting areas to trespassers. The author believes there is no evidence that the presence of the investigator causes nest destructions such as described by Hammond and Forward (1956) for dry-land nesting ducks. During the study, 45 female Canada geese (Branta canadensis) safely accumulated their clutches in ground nests and started to incubate. Humans and dogs destroyed eight nests, but 95% of the remainder hatched successfully.

26. Braun, C. E., K. W. Harmon, J. A. Jackson, and C. D. Littlefield. 1978. Management of National Wildlife Refuges in the United States: its impacts on birds. Wilson Bulletin 90:309-321.

National Wildlife Refuges (NWRs) are located in 49 of the 50 states and encompass more than 13,678,860 ha. Refuges are vital for habitats and overall conservation of many birds. In 1974, fishing was allowed on 171 refuges with fishing waters being stocked on at least 18 refuges. Excessive use of shallow vegetated areas of lakes and streams by wading and boating fishermen can disturb feeding and nesting waterbirds. Various publics have demanded and received access to 42 NWRs for motor boating and water skiing. Obvious and documented impacts of high speed boating are shoreline degradation, disruption of nesting and feeding with loss of production, and displacement of birds. Sport hunting of wildlife was permitted on portions of 184 national wildlife refuges in 1974, primarily for migratory waterfowl but also for resident game birds and big game. Where endangered species are involved, such as whooping cranes (Grus americana) and Mexican ducks (Anas platyrynchos), it is difficult to see the rationale for sport hunting of lookalike species. Some refuges have been used as practice areas for low flying military aircraft, others as convenient and inexpensive routes for highway and utility rights-of-way.

27. Brown, P. W., and M. A. Brown. 1981. Nesting biology of the white-winged scoter. Journal of Wildlife Management 45:38-45.

White-winged scoters (Melanitta fusca) are easily disturbed by human interference such as the recreational boating that often occurs on lakes that white-winged scoters prefer for breeding. According to the senior author, recreational boaters stopped at islands and disrupted nesting, and water ski enthusiasts and power boaters ran over hens and broods.

28. Burger, J. 1981. The effect of human activity on birds at a coastal bay. Biological Conservation 21:231-241.

This paper deals with Jamaica Bay Refuge, which is administered by the National Park Service as part of the Gateway National Seashore. References often are made to human disturbance to loons, gulls, cormorants, and herons, all of which we excluded from coverage. Disturbances were tallied for people walking, worm diggers, horseback riders, joggers, men working, and aircraft. Ducks and brant (Branta bernicla) usually went to the water when disturbed on land, and often were not disturbed when on the water. Further, they were intermediate in response to disturbance, in that they do not immediately return to the area from where they were displaced. Birds generally did not respond to subsonic jets, but they always responded to the supersonic transport jets whenever it passed directly overhead. Birds respond to the supersonic noise by flushing although many returned to where they had been.

29. Burton, R. A., and R. J. Hudson. 1975. Activity budgets of lesser snow geese wintering on the Fraser River Estuary, British Columbia. Wildfowl 29:111-117.

Factors such as disturbance and changes in food availability may alter the feeding routine of snow geese (Chen caerulescens). One critical factor is the efficiency of feeding in relation to the amount of time available. The time spent in flight, both disturbed and undisturbed, was estimated to be at least 0.25 hrs. However, during periods of excessive wind or harassment this level could increase three-fold. Flight was estimated to constitute 1.0% of all time spent in major activities. Nocturnal feeding occurred both in and out of the hunting season. Fluctuating food availability due to changing tide levels seemed more important than hunter harassment. The early autumn migrants invariably first settled at Brunswick Point in October. This marsh was used both day and night for a short time, but hunting pressure during the day soon forced the snow geese on to Reifel refuge. Suitable conditions encountered at Brunswick apparently caused them to return each night.

30. Campbell, L. H. 1978. Patterns of distribution and behavior of flocks of seaducks wintering at Leith and Musselburgh, Scotland. Biological Conservation 14:111-124.

During 1972-73 there was considerable activity on the shore that affected greater scaup (Aythya marila), common goldeneye (Bucephala clangula), and common eiders (Somateria mollissima) between Leith and Seafield sewers, while the retaining walls for land reclamation at the new sewage works were under construction and completed by 1974-75. It seemed that the observed change in distribution pattern was a short-term response to localized increases in disturbance levels.

31. Campbell, L. H., and H. Milne. 1977. Goldeneye feeding close to sewer outfalls in winter. Wildfowl 28:81-85.

Common goldeneyes (Bucephala clangula) were obviously sensitive to sudden loud noises. On 11 occasions when such occurred (for example, blasting or ship sirens) they immediately took flight and left the bay. On 6 days no birds had returned after 2 hours and less than 10 of the original flock returned on the remaining 5 days, although these usually did so within 10 minutes of the incident. While large vessels anchored in the bay had no effect, smaller boats approaching the flock caused the birds to take flight, normally to the southern part of the bay, from whence they gradually returned once the boat departed. Regular disturbance to birds in the sewer was caused by passers-by on the sea-wall. When approaching from the east, people were visible some distance from the flock, which merely swam further offshore. However, from the west, passers-by tended to come into view suddenly close to the sewer, and the birds usually took flight.

32. Campredon, P. 1981. Hivernage du canard siffleur Anas penelope L. en Camargue (France) stationnements et activités [Wintering of the widgeon Anas penelope L. in the Camargue region of (France) wintering grounds and their activities]. Alauda 49:161-193.

Disturbances of Eurasian wigeon by natural predators totaled 361, by man totaled 19, by planes totaled 19, and those for an unknown reason 58 (correspondingly as a percentage of the total disturbances: 82.7%, 3.4%, 3.4%, and 10.4%). Disturbances by man or plane generally affected a greater percentage of individuals at one time, 61.5% for man and 49.6% for planes. Time spent in flight per disturbance for predators varied from 8 sec to 58 sec while 34 sec was the duration of disturbance caused by man, and 9 sec by airplanes. Disturbances by man were chiefly by hunters, fishermen, planes, and especially helicopters at low altitude: these chiefly occurred during the day, and nocturnal disturbances were mostly caused by avian predators. Predators caused localized displacements, but those by man on a small body of water caused a total evacuation. If the disturbance occurred on a larger body of water, ducks regrouped in the middle. Ducks were very sensitive to fishermen who went into the water. Man's disturbances modified the periodicity of ducks' activities, and seriously affected feeding.

33. Catchpole, C. K., and C. F. Tydeman. 1975. Gravel pits as new wetland habitats for the conservation of breeding bird communities. Biological Conservation 8:47-59.

The mallard (Anas platyrhynchos) comprised 8.0% and the tufted duck (Aythya fuligula) 2.4% of the total breeding population in 10 sites studied. Reclamation, pollution, and recreation are obvious threats, but new pressures are continually arising. As the demand for water-based recreation continues to increase, it seems likely that gravel pits will face even more pressure than natural wetlands.

34. Choate, J. S. 1966. Breeding biology of the American eider (Somateria mollissima dresseri) in Penobscot Bay, Maine. Masters of Science thesis, University Maine, Orono. 173 pp.

A study area visited daily by Milne (1963) was compared with a relatively undisturbed control area. Although success of common eider was somewhat lower (3%) in the disturbed area, the difference was not significant. However, in this present study success was significantly lower in the disturbed area.

35. Choate, J. S. 1967. Factors influencing nesting success of eiders in Penobscot Bay, Maine. Journal of Wildlife Management 31:769-777.

Human disturbance was indirectly responsible for lowered nesting success. Observations from a blind showed that after an investigator left an island, herring gulls (Larus argentatus) and great black-backed gulls (Larus marinus) returned much sooner than common eiders (Somateria mollissima). Before common eiders returned, nests were highly vulnerable to predation by gulls. When the island was revisited one or more times on the same day, after setting nets or banding common eiders, many newly destroyed nests were evident. Gulls were seen flying back to the island as soon as workers left, and they no doubt destroyed many nests before the common eiders returned. Human disturbance did not appear to directly cause much nest desertion. A few clutches apparently were lost because of overexposure to heat when nests were checked on hot, sunny days. Overheating occurred when many common eiders were flushed from their nests for 2 hours or more. Goose Island, with more than twice as many visits, had 27% nest success--about two-thirds that for East Goose Rock (40%); the difference significant (P < 0.01).

36. Combs, D. L. 1987. Ecology of male mallards during winter in the Upper Mississippi alluvial valley. Ph.D. thesis, University Missouri, Columbia. 223 pp.

Hunting pressure was probably the primary factor influencing habitat shifts during early winter from Unit A and greentree reservoirs on Duck Creek Wildlife Management Area to unhunted areas on Mingo National Wildlife Refuge (MNWR). During all 3 years of this study, Unit A was used extensively by mallards (Anas platyrhynchos) before and after waterfowl hunting season but received little use during the season. Non-hunting disturbance (e.g. vehicular traffic) may have also influenced mallard distribution in the Mingo Swamp and warrants additional research. Lack of hunting probably contributed to reduced alert activity during early spring, and habitat shifts to unhunted areas on MNWR may have influenced a midwinter decline in alert behavior during 1985-86. Alert behavior was also greater in shallow habitats than in open water zones where disturbance was minimal because of distance from roads.

37. Cooch, F. G. 1958. The breeding biology and management of the blue goose (Chen caerulescens). Ph.D. thesis, Cornell University, Ithaca. 235 pp.

The fear of dogs was amply demonstrated at Boas River in 1953 when "waves" of snow geese ran wildly across the tundra pursued by a stray dog. The reaction of snow geese toward intrusion by man is variable, but seems density dependent. Development of tameness was noticed at Boas River, where the same route was followed each day and nests were always approached from the same direction. If the direction of approach was changed a completely different reaction was seen. In the first case, the birds would move away when the investigator was within 6.1 m of the nest, while in the second case birds moved at more than 45.7 m. Females followed a definite ritual when returning to the nest, after turning eggs; or when disturbed by predators or low-flying aircraft. When dense colonies suddenly became reduced to a few scattered incubating pairs, remaining females frequently deserted nests taking only dry young. When geese were disturbed by humans when one gosling was strong enough to follow, the rest of the brood was left to its fate.

38. Cooch, F. G. 1965. The breeding biology and management of the northern eider (Somateria mollissima borealis) in the Cape Dorset area, Northwest Territories. Canadian Wildlife Service Wildlife Management Bulletin, Ser. 2, No. 10. 68 pp.

Frequent flushing of birds in the study area and subsequent exposure of eggs to predators seemed to result in heavier than normal egg loss for the common eider. Personnel participating in the investigations agreed that the birds on the study area seemed to be tamer in 1956 than in 1955. There is a possibility that because of greater tameness the birds returned to their nests more quickly or were less prone to desert after being disturbed, thus reducing predation. Undoubtedly some desertion can be attributed to the presence of people in the nesting area.

39. Cooke, A. S. 1987. Disturbance by anglers of birds at Grafham Water. ITE Symposium No. 19:15-22.

Grafham Water in Cambridgeshire is one of the most important wintering sites for waterfowl in Britain. Sailing there has relatively little impact on waterfowl because it occurs only intermittently and disturbance is more or less confined to deep water avoided by most waterfowl. However, bank and boat fishermen arrive in large numbers on every day during the fishing season, and often fish the shallow, sheltered bays and creeks favored by the birds. Detailed observations and results are presented for effects of fishing on numbers and distribution of waterfowl, grebes (Podiceps and Tachybaptus), and Eurasian coot (Fulica atra); an increase of waterfowl at the conclusion of the angling season; effects of the close of angling on distribution of wildfowl species; tolerance distance of mallards (Anas platyrhynchos) in specific areas in relation to disturbance and changes after angling closed; comparative approachability of water birds by area of the reservoir; and overall ranking orders for species based on bird counts and controlled approach studies. But ranking lists derived for Grafham might not be applicable elsewhere.

40. Cooper, J. A. 1978. The history and breeding biology of the Canada geese of Marshy Point, Manitoba. Wildlife Monograph 61, The Wildlife Society, Washington, D.C. 87 pp.

During this study, 2,889 nest visits were made to 578 nests (first, continuation, and renests) for an average of five observer disturbances per nest. Only one desertion during the study was believed to have resulted from my activities.

This is in contrast to findings of others where observer disturbance has been cited as a cause of nest abandonment by Canada geese (Branta canadensis): Martin (1964:48) who concluded that his investigation contributed to 40% of the total nest losses at Ogden Bay, Utah, Dow (1943:13) who attributed 23% of the nest destruction in his study at Honey Lake, California, to man's activities, and in a more recent study, Hanson and Eberhardt (1971:23), who found that the Hanford, Washington, Canada geese deserted those nests visited most often at a higher rate (12 of 16 nests) than those visited least (3 of 7 nests, P > 0.05). Conversely, Geis (1956:416), working with Canada geese in Montana, concluded that disturbance by the investigator was not believed to be an important cause of desertion. Similarly, Weigand et al. (1968:903), who made daily visits to nests of captive geese in Michigan, could assign no nest losses to human disturbance.

41. Coulter, M. W., and W. R. Miller. 1968. Nesting biology of black ducks and mallards in northern New England. Bulletin 68-2, Vermont Fish and Game Department, Montpelier. 73 pp.

Tolerance to disturbance by waterfowl was an individual trait. Hens occasionally deserted their clutches after the first disturbance, but in 30 instances where hens were trapped only one deserted. Hen trapping was attempted at 291 nests and 223 (80%) hens were captured. Desertion of nests after a trap was set was 6% for ring-necked ducks (Aythya collaris), 9% for American black ducks (Anas rubripes) and 26% for mallards (Anas platyrhynchos). Ten of 18 desertions occurred with a group of especially intolerant mallards on Dameas Island. Certain other mallards were more tolerant and only 16% of 49 deserted nests at other islands. Nest abandonment was not as common during the last week of incubation. Human activity on islands is detrimental to successful waterfowl production; the presence of people may discourage nesting. Chances for avian predation were increased because: (1) some potential avian predators returned to the islands sooner than did most ducks, (2) hens flushed generally left nests uncovered, (3) flushing of hens often resulted in pieces of down being left on surrounding vegetation. In certain cases dispersal of broods caused losses.

42. Craighead, J. J., and D. S. Stockstad. 1961. Evaluating the use of aerial nesting platforms by Canada geese. Journal of Wildlife Management 25:363-372.

The exposed position of many nest boxes seemed to invite greater desertion but greatly reduced predation by the added security of an elevated site. Much desertion of Canada Geese (Branta canadensis) could be attributed to the disruptive influence of fishermen and sightseers who frequently came close to exposed nesting platforms in Flathead Lake or who occasionally inspected them at close range. There is little doubt that this human interference could be reduced by selecting more secluded sites.

43. Craven, S., and J. Ellis. 1982. Assessment of techniques used in a 5-year program of Canada goose dispersal. Page 56 in M. A. Johnson, ed. Transactions of the Canada goose symposium, 28-29 April 1982, Bismarck, N. Dak. The Wildlife Society, North Dakota Chapter and Central Mountains and Plains Section.

Problems associated with a large concentration of Canada geese (Branta canadensis) at Horicon National Wildlife Refuge prompted state and federal wildlife agencies to attempt a 50% reduction of the goose flock during the period 1976-1980. Cultivated foods were removed from the refuge, and water and sanctuary were reduced. Early in the program denial of sanctuary was identified as the critical component of successful flock reduction. Thus disturbance, or "hazing" by airboats, propane exploders, and a combination of the two became the primary techniques. Observations of Canada geese neckbanded at Horicon both within and between years suggested a movement of some birds to Illinois wintering areas during October; a time when, in absence of disturbance, they would likely have remained in Wisconsin. Increased mortality associated with a near doubling of the harvest quota (28,000 - 50,000) from 1976-1978 also appears to have been an important component of flock reduction.

44. Cronan, J. M., Jr. 1957. Food and feeding habits of the scaups in Connecticut waters. Auk 74:459-468.

Human activity did have a strong effect on lesser scaup (Aythya affinis) feeding. Areas that were heavily hunted were not subject to lesser scaup feeding during the hunting season. During the fall and spring many of the feeding areas were not utilized when fishing and boating activities were going on. Even during mid-winter when a comparatively balmy Saturday or Sunday encouraged human activity along the shore, the lesser scaup would not be present in their normal feeding areas.

45. Davis, R. A., and A. N. Wiseley. 1974. Normal behavior of snow geese on the Yukon-Alaska North Slope and the effects of aircraft-induced disturbance on this behavior, September, 1973. Chapter II in W. W. H. Gunn, W. J. Richardson, R. E. Schweinburg, and T. D. Wright, eds. Studies on snow geese and waterfowl in the Northwest Territories, Yukon Territory and Alaska, 1973. Arctic Gas Biological Report Service, Vol. 27.

Up to 400,000 snow geese (Chen caerulescens) congregate on the North Slope where they accumulate energy for fall migration. This study documented undisturbed behavior and evaluated effects of overflights. Snow geese were observed at five camps along the North Slope during 663 hours for over 175 flocks; behaviors occurred during 73 natural disturbances and 163 non-experimental overflights. Experimental overflights at 2.5-hour intervals with a Cessna 185 Bell 206-B helicopter were made. Undisturbed snow geese spent 57% of daylight hours feeding (juveniles alone 65-70%). Snow geese were equally prone to flush from fixed-wing aircraft and helicopters, flushed at greater distances from helicopters, but flew longer in response to fixed-wing aircraft. Snow geese accommodated to a varying extent to increased frequencies of overflights. Non-experimental aircraft disturbances averaging 0.25 per daylight hour resulted in a potential decrease of 2.6% in time spent feeding. Experimental overflights at 2-hour intervals by fixed-wing aircraft caused an 8.5% decrease in feeding time, and could cause a reduction of 20.4% in energy reserves for juveniles; the corresponding figure for a helicopter is 9.5%.

46. Dennis, D. G., and N. R. North. 1984. Waterfowl use of the Lake St. Clair marshes during migration in 1968-69, 1976-77, and 1982. Pages 43-52 in S. G. Curtis, D. G. Dennis, and H. Boyd, eds. Waterfowl studies in Ontario, 1973-81. Occasional Paper No. 54, Canadian Wildlife Service.

Factors contributing to increased waterfowl use were larger local mallard (Anas platyrhynchos) and Canada goose (Branta canadensis) populations, more baited sanctuaries, increase in quantity of waterfowl food plant species as a result of higher lake levels, and the establishment of a National Wildlife Area closed to hunting. Factors that reduced waterfowl use included habitat destruction caused by agricultural drainage; marina developments on wetlands, with resulting increased boat traffic disturbing waterfowl; increased public hunting on areas that had previously been hunted at a low intensity; and population declines in species such as American black ducks (Anas rubripes) and ruddy ducks (Oxyura jamaicensis)

47. Dennis, D. G., G. B. McCullough, N. R. North, and R. K. Ross. 1984. An updated assessment of migrant waterfowl use of the Ontario shorelines of the southern Great Lakes. Pages 37-42 in S. G. Curtis, D. G. Dennis, and H. Boyd, eds. Waterfowl studies in Ontario, 1973-81. Occasional Paper No. 54, Canadian Wildlife Service.

Limited waterfowl use during both spring and autumn is due to scarcity of aquatic vegetation, although disturbance by pleasure craft also has a minor influence. Mallard (Anas platyrhynchos) and Canada goose (Branta canadensis) population rose chiefly due to more use of legal baiting by hunting clubs, and establishment of the St. Clair National Wildlife Area in 1974 increased American black duck (Anas rubripes) use. Use by canvasbacks (Aythya valisineria), redheads (Aythya americana), and common mergansers (Mergus merganser) increased much during both spring and autumn as a result of extensive disturbance by boat traffic in the better habitat located in area D along the east shore of Lake St. Clair. Although increased ship traffic in the Outer Bay due to the Nanticoke Industrial Development will not greatly disturb waterfowl, increased potential for an oil spill exists for large portions of the continental populations of both canvasbacks and redheads. Shooting pressure forces most birds to leave shortly after opening of the hunting season. Lesser scaup (Aythya affinis) are moderately disturbed by increased power boat traffic.

48. Dennis, D. G., and R. E. Chandler. 1974. Waterfowl use of the Ontario shorelines of the southern Great Lakes during migration. Pages 58-65 in H. Boyd, ed. Canadian Wildlife Service studies in eastern Canada, 1969-73. Canadian Wildlife Service Report, Ser. No. 29.

In several bays there is not much boat traffic and large numbers of diving ducks are able to feed undisturbed. Baited sanctuary areas throughout the marshes increase the carrying capacity for dabbling ducks and Canada geese (Branta canadensis). Many redheads (Aythya americana) and canvasbacks (Aythya valisineria) are present during both spring and autumn in one section of the Detroit River near the mouth of the Canard River, which has limited boat traffic. Although marsh habitat appears to be fair quality, human disturbance and absence of suitable sanctuaries causes lower use by waterfowl than expected. Some dabblers use the area less during autumn because of power boat traffic. Although disturbance during autumn also affects diving ducks, they can rest on the open waters of Lake Erie during the times of peak disturbance on the bay. Dabbling duck habitat is of low quality, except in the Grand River marshes, where heavy hunting pressure and lack of suitable sanctuaries cause most of the dabbling ducks to leave shortly after opening day.

49. Denson, E. P., Jr. 1964. Comparison of waterfowl hunting techniques at Humboldt Bay, California. Journal of Wildlife Management 28:103-120.

The behavior of birds hunted by scullers differed radically from day to day. Sometimes nearer ducks would "leapfrog" no more than 200 yd (188.2 m) while at other times entire flocks would rise and move for 1 mile or more. Scullers disturbed birds and made them more difficult to approach, but movement of flocks of brant (Branta bernicla) by scullers were temporary, and probably benefitted shooters in open-water and shore blinds. Waterfowl suffered far more harassment from amateur crab fishermen and pleasure boaters equipped with high-powered outboard motors. Daily pressure exerted by hunters on the spit and the harassment by boaters have been chiefly responsible for eliminating the brant population which once spent November and December on Humboldt Bay. A sector of the bay should be closed to boats from October through April, when large numbers of waterfowl are present. An area of 200-300 acres (81-121.5 ha), less than 10% of the bay, should protect the birds.

50. Denson, E. P., Jr., and S. L. Murrell. 1962. Black brant populations of Humboldt Bay, California. Journal of Wildlife Management 26:257-262.

Few bays along the Pacific Coast of contiguous states have escaped development for commercial or recreational purposes. In most cases this process has greatly reduced the value of bays to waterfowl. Intensive recreational and industrial uses are rapidly depriving brant (Branta bernicla) of food and shelter on California bays. So few birds are present prior to January and February that starting the season one or more months before the first of January has little effect on overall harvest. However, hunters concentrate on the early arrivals and, at times, have driven these small flocks from the Bay.

51. Dillon, S. T. 1956. A nine-year study of fall waterfowl migration on University Bay, Madison, Wisconsin; Part 1. Transactions of the Wisconsin Academy of Science, Arts and Letters 45:31-57.

Fishing influences the use of the Bay by waterfowl. This sport is extremely popular during the fall months and the passage of boats through the Bay is often a source of considerable disturbance. On very calm days waterfowl of all species present tend to gather on the open waters of the lake. This may reflect a preference on their part or it may be the result of disturbance by the generally increased boat traffic under such conditions.

52. Dow, J. S. 1943. A study of nesting Canada geese in Honey Lake Valley, California. California Fish and Game 29:3-18.

On March 27, 1939, a Canada goose (Branta canadensis) nest containing six eggs was found on top of a haystack. On April 20, the incubating bird was disturbed by photographers and left the nest for approximately 2 hours during the heat of the day. The goose continued to incubate until June 22, when the eggs were taken, examined and found to contain dead embryos after at least 87 days of incubation. On March 18, 1940, a goose nest containing two eggs was found on the top of one end of a large haystack, more than 18 ft (5.5 m) from the ground. Two or more wagon loads of hay were being taken from the opposite end of the stack each day. A last visit to the nest revealed that the goose hatched two goslings in spite of the fact that she had been disturbed each day during the incubation period. Overall, six desertions were directly traced to man's activities. The disturbances of irrigators traveling the canal banks with their dogs were responsible for five, and one was deserted when the author flushed an incubating goose from her nest while two crows were circling overhead. Although the eggs were carefully covered, the goose never returned.

53. Duebbert, H. F., and J. T. Lokemoen. 1980. High duck nesting success in a predator-reduced environment. Journal of Wildlife Management 44:428-437.

Abandonment rates were low: 21 of 1,062 nests (2%) were abandoned during all years. Nearly all abandonments were the result of interference by the researcher when nests contained one to five eggs. Another 31 nests had other fates. Four were destroyed by search vehicles.

54. Dwernychuk, L. W., and D. A. Boag. 1972. How vegetative cover protects duck nests from egg-eating birds. Journal of Wildlife Management 36:955-958.

To simulate the condition of waterfowl nests during the laying period, the authors followed the history of 128 artificial nests that varied in visibility. Among these nests, success in avoiding egg loss to birds was directly correlated with the presence of overhead cover. However, even among those nests that were completely screened by vegetation, 34% were lost. It seemed obvious to the authors that egg-eating birds were reacting to other visual cues such as disturbed vegetation or nest markers left at and around the nests. Disturbed vegetation is much more likely to be the visual cue used by the predatory birds, because, in spite of all efforts to the contrary, it was impossible to approach and leave nest sites, particularly in dense vegetation, without leaving some vegetation disturbed.

55. Dzubin, A., and J. B. Gollop. 1972. Aspects of mallard breeding ecology in Canadian parkland and grassland. Pages 113-152 in Population ecology of migratory birds, papers from a symposium held at the Migratory Bird Population Station, Laurel, Maryland, 9-10 October 1969. U.S. Department of Interior, Fish and Wildlife Service, Wildlife Research Report 2.

The authors believed that wild mallards (Anas platyrhynchos) breeding under natural conditions are poor subjects on which to accumulate statistically sound population parameters. They believed this species is particularly sensitive to human interference, especially during brood-rearing.

56. Earl, J. P. 1950. Production of mallards on irrigated land in the Sacramento Valley, California. Journal of Wildlife Management 14:332-342.

Some desertions by mallards (Anas platyrhynchos) could have been caused by too frequent interference on the part of the observer. Early in the nesting period, nests were visited every other day. The time between visits later was extended to a week. The only other large loss by predation was in the wheat. The author believes that losses were due in part to trails made by himself in the process of visiting the nests. The author did not believe that predators, starting at random at the edge of a large wheat field, could account for almost a third of the nests without being led to the nests by an investigator.

57. Eberhart, L. E., R. G. Anthony, and W. H. Rickard. 1989. Movement and habitat use by Great Basin Canada goose broods. Journal of Wildlife Management 53:740-748.

Broods of Canada geese (Branta canadensis) seemed to be most susceptible to human disturbance during the first few weeks following hatching, but older broods were relatively tolerant of repeated human disturbance. Eight broods residing in the lower stretch of the river had access to shoreline areas within their home ranges that were adjacent to human habitation. These broods showed a significant avoidance of human habitation (P = 0.02) and concentrated their activities in portions of their home ranges comparatively free from human disturbance.

58. Edington, J. M. 1980. Recreation and wildlife. Nature in Wales Newsletter 3:10-16.

Edington reviews wildlife-based (bird-watching, angling, and shooting), aesthetic (scenic), and active recreation (climbing, caving, skiing, and sailing). Situations discussed are overzealous bird-watchers, observation blinds, protective legislation, shooting, lead shot, angler's weights, discarded nylon lines, predator control, trampled vegetation, and sailing as related to disturbances of overwintering waterfowl.

59. Edwards, R. W., and D. V. Bell. 1987. The impact of angling on wildlife. Pages 161-166 in Proceedings of the 4th British Freshwater Fisheries Conference, 1-3 April 1985, University of Liverpool.

Recreational activities such as boating and angling have been reported to disturb some bird species. There are frequently interactions between these activities. Wildlife protection needs wider use of refuges and temporal restrictions on recreational activities at critical stages of overwintering and breeding. Interference of breeding birds which nest along the margins of water bodies by angling and other activities needs further investigation.

60. Edwards, R., and D. Bell. 1985. Fishing in troubled waters. New Science, No. 1446, 7th March:19-21.

At the Llandegfedd reservoir in the Usk Valley, where the fishing season has recently been advanced by 2 weeks to 20 March, anglers choose parts of the reservoir which birds such as Eurasian wigeon (Anas penelope) and green-winged teal (Anas crecca) also prefer. The reservoir is an important trout fishery, but it also supports the highest number of overwintering waterfowl in South Wales. As a result of the anglers' intrusion, these birds gathered in the center of the reservoir during the day, away from the shallow areas and shore where they would normally feed on grasses and herbs. Birds dispersed from the site after a few days, possibly because of increased sailing activity in central areas. The number of Eurasian wigeon, for example, fell from over 400 to about 60 within a week. This contrasted with a much more gradual emigration from a nearby, undisturbed site at Slimbridge on the Severn Estuary.

61. Einarsen, A. S. 1965. Black brant, sea goose of the Pacific coast. University of Washington Press, Seattle. 142 pp.

A plane flying even 1 or 2 miles away may cause either single or flocked brant (Branta bernicla) to take to the air. In some areas, boating activity continually molests birds seeking food in their usual places. During the last 5 years high-speed boats are commonly used from British Columbia to San Quintin Bay in northern Baja California. The use of power dredges intimidates feeding birds in daylight and tends to destroy eelgrass beds. A boating disturbance was observed on Mission Bay, San Diego Harbor, on January 19, 1958. Here at low tide the brant geese could find sanctuary only in small elbows off the main channel in the bay, where they could drift up a mud-bottomed slough for perhaps a few hundred yards (a few hundred meters); but the continual traffic of high-speed boats, traveling at velocities of from 8-40 mph (12.9-64.4 km/hr), prohibited the birds from foraging on eelgrass beds or occupying open water in the channel. Boating activity on Humboldt Bay, California, is also forcing brant geese to spend their nights on the ocean. Serious losses result, for sleeping brant drift unconsciously into the breakers where the heavy sand content beats them down to the ocean floor and they wash ashore as "sanded" dead.

62. Eisenhauer, D. I., and C. M. Kirkpatrick. 1977. Ecology of the emperor goose in Alaska. Wildlife Monograph 57, The Wildlife Society, Washington, D.C. 62 pp.

Emperor geese (Chen canagica) had the highest rate of nesting success because they were more reluctant than other species to leave their nests when the authors were in the area. For the 3 years, destruction of nests by natives amounted to 34% of the total number of unsuccessful emperor goose and brant (Branta bernicla) nests on the study area and 37% of the total nest losses attributed to predation; this probably will persist for many years. Increased human disturbance in 1972 corresponded to increased desertions and increased egg predation in 1972. Human-induced desertion amounted to 0 in 1971, 4.4% in 1972, 0.9% in 1973, and 1.9% of all eggs overall. About 57% of all emperor goose eggs lost on the study area were from nests classified as successful; investigator disturbance contributed to predation on eggs. Human disturbances frequently caused broods to break up and scatter, or frightened parents to run ahead of their goslings, and undoubtedly caused significant brood mortality. Banding operations can increase the predation of glaucous gulls (Larus hyperboreus) on young waterfowl.

63. Ellig, L. J. 1955. Waterfowl relationships to Greenfields Lake, Teton County, Montana. Montana Fish and Game Department Technical Bulletin No. 1. 35 pp.

Human interference is thought to have caused the desertion of three nests containing one egg each and five with complete clutches. Sixteen inactive deserted nests or nest forms of five species with one to nine eggs each were found, suggesting that females not uncommonly abandon uncompleted nests without human interference. Six nests were deserted for unknown reasons. Human intrusion is not believed to have increased nest vulnerability to striped skunks (Mephitis).

64. Ely, C. R., and D. G. Raveling. 1984. Breeding biology of Pacific white-fronted geese. Journal of Wildlife Management 48:823-837.

Only one human-induced and one natural nest desertion occurred for greater white-fronted geese (Anser albifrons) constituting 2% of 102 nests.

65. Evans, C. D., and K. E. Black. 1956. Duck production studies on the prairie potholes of South Dakota. U.S. Department of Interior, Fish and Wildlife Service, Special Science Report--Wildlife No. 32. 59 pp.

Human interference such as continual activity or a brood beatout, does not diminish use except for the occasional brood driven ashore during the actual beatout. The authors believed that even that brood driven ashore is likely to return once the activity has subsided.

66. Evans, C. D., A. S. Hawkins, and W. H. Marshall. 1952. Movements of waterfowl broods in Manitoba. U.S. Department of Interior, Fish and Wildlife Service, Special Scientific Report Wildlife: No. 16. 47 pp.

Human intrusion was found to influence brood movement in some instances, but it often had little effect and some broods could not be driven from their potholes.

67. Evans, R. D., and C. W. Wolfe, Jr. 1967. Waterfowl production in the Rainwater Basin area of Nebraska. Journal of Wildlife Management 31:788-794.

Miscellaneous causes of nest failure included human disturbance, flooding, burning, and undetermined. Three nests of blue-winged teal (Anas discors) were abandoned because of humans.

68. Evenson, D. E. 1974. Migratory waterfowl use of Houghton Lake, Michigan. Masters of Science Thesis, University Michigan, Ann Arbor. 105 pp.

Disturbances from occupied hunting blinds and boats caused birds to seek open waters for refuge during the day. These factors were more significant in preventing ducks from using the Middle Grounds than for any other location on the lake. In pre-season counts, ducks using the Middle Grounds made up 20.7% of duck-use days; after hunting started only 7.4% of the duck-use days were in the Middle Grounds. [See the following two papers, which seem to be based on this thesis.]

69. Evenson, D. E., and C. X. Hopkins, Jr. 1973. Waterfowl at Houghton Lake: including an analysis of the influence of food resources and disturbances on waterfowl use. Technical Bulletin No. 73-3, Michigan Department of Natural Resources, Lansing. 69 pp.

The largest-sized disturbances in 1972 (averaging 1,502 birds) were caused by hunters having a blind built directly onto the boat. The second largest disturbance factor on average was the authors' observation study. The value of 372 birds per disturbance is probably out of proportion to the actual disturbance effect on the lake because all disturbances the authors created were tallied. Hunters utilizing floating blinds, who were the most numerous type of hunters on the lake, caused an average disturbance of 232 birds. Non-hunting disturbance factors caused fewer and smaller disturbances than hunters did during the hunting season. However, in pre-season observations, fishermen created five disturbances averaging 537 birds per disturbance.

70. Evenson, D., C. Hopkins, and G. Martz. 1974. Waterfowl and waterfowl hunting at Houghton Lake. Michigan Department of Natural Resources, Wildlife Division, Information Circular 171, Lansing. 7 pp.

Disturbances to waterfowl on Houghton Lake during early fall and hunting season of 1972 occurred from at least six different sources including boating, fishing, hunting, this study, aircraft, and a bald eagle (Haliaeetus leucocephalus). At least 85% of the disturbances involved boats and 53% of the disturbances directly involved hunting activities. The hunting season disturbances affect more ducks than pre-season disturbances primarily because there were more ducks on the lake during the hunting season than before it. During the hunting season of 1972, we estimated that 408,000 waterfowl were involved in disturbances that occurred on the lake. Obviously, individual birds were disturbed more than once per day. When the number of birds disturbed is compared with the duck-use days for the season (408,000/268,000), it can be seen that each duck and American coot (Fulica americana) was disturbed about 1½ times per day on the average. Weekend disturbance rates were about 1½ times greater than those during the week. In spite of the disturbances which occurred, ducks were never seen to leave the lake in 1972 as a result of harassment.

71. Figley, W. K., and L. W. VanDruff. 1982. The ecology of urban mallards. Wildlife Monograph 81, The Wildlife Society, Washington, D.C. 40 pp.

During January-March, many mallards (Anas platyrhynchos) were wary of humans, often flying 60 m in advance of an approaching boat. They were reluctant to take food from people. During the rest of the year, lagoon ducks were much less apprehensive and paid little attention to moving boats. Increased wariness during winter may be due to an increased number of wild migrant birds in the Angelholm flock. One of seven factors contributing to severe brood losses in the lagoon was the capturing and scattering of broods by people. Lesser (pers. comm.) noted that the total hatch of 28 and 13 mallard ducklings during 1974 and 1975, respectively, on a small campus pond was destroyed by cats and dogs.

72. Fraser, M. W. 1987. Reactions of sea-ducks to windsurfers. British Birds 80:424.

The author on 22 June 1981 was watching a flock of 400 common eiders (Somateria mollissima) about 200 m close inshore and about 220 black scoters (Melanitta nigra) 400 m out to sea. Suddenly the common eiders took off eastward to the open sea; a few seconds later, the black scoter flock reacted similarly. The author then noticed that a windsurfer had come into view 500 m to the west and 250 m from the shore around a rocky headland. Some 10 minutes after he had disappeared, the common eiders made their way back, but the black scoters were not seen again. By contrast to the sail and engine-powered dinghies and small boats, the appearance of the windsurfer produced instant panic. Dr. C. H. Fry then inserted an editor's comment as follows: "Casual observations on the Ythan Estuary, Grampian, which I walked for an hour or two in most weeks up to 1986, suggested that none of the wildfowl was much disturbed by the activities of up to about 20 windsurfers who were often present. The ducks, mainly common eiders, long-tailed ducks (Clangula hyemalis), red-breasted mergansers (Mergus serrator), common goldeneyes (Bucephala clangula) and Eurasian wigeons (Anas penelope), simply moved a minimum distance, 100-300 m perhaps, out of the way. The wildfowl might, of course, initially have been scared; if so, they adapted rapidly."

73. Frederick, R. B., W. R. Clark, and E. E. Klaas. 1987. Behavior, energetics, and management of refuging waterfowl: a simulation model. Wildlife Monograph 96, The Wildlife Society, Washington, D.C. 35 pp.

A stochastic simulation model designed to test alternative management schemes on refuging waterfowl populations was constructed from data on fall-migrating snow geese (Chen caerulescens) at the DeSoto National Wildlife Refuge. Components of the model include population level, food density and distribution, food-searching flight characteristics, feeding rates, activity and energy budgets, migration rates, and effects of weather, hunting pressure, and land management practices on the system. Data were collected to test the model's validity. Refuge population level was not sensitive to shifts (±20%) in the input values of 25 selected parameters, but hunting mortality and daily foraging distances were sensitive to several combinations of parameter perturbations. Model outcome was most sensitive to changes in digestive efficiency, mean food density, and the proportion of refuge fields in which food was available. In other model experiments, increased hunting pressure caused significant (P < 0.05) increases in hunting mortality and a reduction in the refuge population. The effect of hunting was less important in reducing waterfowl population size than the associated disturbance of feeding snow geese by hunters.

74. Fredrickson, L. H., and R. D. Drobney. 1979. Habitat utilization by postbreeding waterfowl. Pages 119-131 in T. A. Bookhout, ed. Waterfowl and wetlands--an integrated review. North Central Section, The Wildlife Society, La Crosse Printing Co., La Crosse, Wisconsin.

Reduced caloric intake can have a dramatic effect on the time needed for waterfowl to replenish fat reserves. Reducing the daily caloric intake by 19% (390 kcal/day) more than doubles the estimated time required for fat replenishment, but these estimates represent a simplified case and actual requirements may be different. Concentrating waterfowl creates two problems that could adversely affect their energy budgets. First, food supplies become depleted more rapidly. Decreased food availability necessitates increased foraging time and/or longer foraging flights for those species that field-feed. Secondly, hunting pressure tends to increase in areas where waterfowl concentrate. Harassment by hunters could increase movements and reduce time available for foraging.

75. Fredrickson, L. H., and F. A. Reid. 1988. Waterfowl use of wetland complexes. Pages 1-6 in Managing waterfowl habitats: breeding, migrating, wintering. Gaylord Memorial Laboratory, University of Missouri, Puxico, Missouri/U.S. Department of Interior, Fish and Wildlife Service, Office of Information Transfer, 1025 Pennock Place, Suite 212, Fort Collins, Colo. 80524.

Refuge management may require manipulation of soil and water to produce habitat structure or essential foods. Production of foods does not assure that waterfowl will use them. Foods only are accessible if appropriate water depths are maintained during critical time periods, habitats are protected from disturbance, and habitats that provide protein and energy are close together. Disturbance is particularly important, and recognition of the influence of disturbance on access to and acquisition of needs throughout the annual cycle is essential. Subtle effects caused by bird watchers, researchers, and refuge activities during critical biological events may be as detrimental to waterfowl populations as hunting or other water-related recreational activities such as boating. At certain locations, predators or activities associated with barge traffic, oil exploration, or other industrial or military operations are detrimental.

76. Fruzi ski, B. 1977. Feeding habits of pink-footed geese (Anser fabalis brachyrhynchus) in Denmark during the spring passage in April 1975. Danish Review of Game Biology 10:1-11.

Because of the very narrow isthmus between the North Sea and the Nissum fjord and the considerable disturbance there by man and vehicles the geese often fed outside the area during day-time. During the feeding period at the Fiilso area the pink-footed geese were very sensitive to disturbance, (e.g. by farmers and vehicles). The "tolerance distance" was generally about 300 m, and only exceptionally 200 m during windy and rainy days. Geese usually fed and rested in the middle of the fields, far from roads, where they were most secure. Often disturbed at midday, they moved to the edges of the area into grassland where no farm work was being done.

77. Gauthier, G., J. Bédard, and Y. Bédard. 1984. Comparison of daily energy expenditure of greater snow geese between two habitats. Canadian Journal of Zoology 62:1304-1307.

Snow geese (Chen caerulescens) flew mostly when disturbed or between the marsh and adjacent farmland, and these flights were of short duration.

78. Geis, M. B. 1956. Productivity of Canada geese in the Flathead Valley, Montana. Journal of Wildlife Management 20:409-419.

Disturbance by the investigators was not believed to be an important cause of desertion, since visits were short and the Canada geese (Branta canadensis) were not kept away from the nest long enough to cause chilling of the eggs. Human disturbance over extended periods apparently did increase the desertion rate. This was indicated on two islands in the lake where people were living during part of one nesting season. In one case six out of eight nests were deserted, and in the other six out of nine nests were deserted. In years of no human disturbance, nesting success was above average on these two islands.

79. Gilbert, B. 1977. Uncle Sam says SCRAM! Audubon 79:42-55.

The general objective was to make the Horicon National Wildlife Refuges less attractive to Canada geese (Branta canadensis). To accomplish this, acreage previously used for growing goose food was reduced, and a plan was devised to harass, haze, and frighten Canada geese away from Horicon as they arrived in late fall. In summer, an aircraft, an airboat, gas-powered exploders, assorted firecrackers, rockets, and scarecrow-type devices were assembled. In 1965 the peak Canada goose population at Horicon was estimated at 120,000 birds. In November 1966 after hazing, peak population was 150,000. The Fish and Wildlife Service later began making specific plans to again harass Horicon Canada geese to reduce the peak fall population of Canada geese at Horicon from 200,000 to 100,000 by 1980.

80. Girard, G. L. 1941. The mallard: its management in western Montana. Journal of Wildlife Management 5:233-259.

Before hunting season, it is not unusual to see mallards (Anas platyrhynchos) feeding at any time of the day in the wheat fields, but most of the field feeding takes place in the evening and at night. The largest flights return to the water between 7:30 and 8:30 a.m. During the hunting season, with legal shooting hours from 7:00 a.m. to 4:00 p.m., practically all mallards return to water areas between 6:30 a.m. and 7:l5 a.m., and leave in large flocks between 4:30 and 6:00 p.m. After hunting season, they again change their habits.

81. Glover, F. A. 1956. Nesting and production of the blue-winged teal (Anas discors Linnaeus) in northwest Iowa. Journal of Wildlife Management 20:28-46.

In 1948 one blue-winged teal nest was destroyed by bluegrass seed-stripping machinery. Another blue-winged teal nest was deserted by the female after curious workmen visited the nest several times in a day. A teal nest in Whitford's Slough in 1949 apparently was deserted by the female after being flushed by the investigator. This was unusual, for most of the females generally returned to their nests within a few hours. At Barringer's Slough in 1949, an incubating female was unintentionally stepped on by the investigator while searching dense nesting cover. Two of her eggs were broken. The female flew about 30 yd (28.2 meters) and landed in dense vegetation. Damaged eggs were carefully removed from the nest and the cover returned to its original appearance. A recheck on the nest a week later revealed that the female had successfully brought off a brood of ducklings. It is doubtful if flushing the ducks from nests had a detrimental effect on success. Often successful nests found in Dewey's Pasture in 1949, nine were located by flushing the female. At Whitford's Slough, two of the three successful nests were found by flushing the female.

82. Goss-Custard, J. D., and K. Charman. 1976. Predicting how many wintering waterfowl an area can support. Wildfowl 27:157-158.

There is often a need to predict whether or not wintering waterfowl displaced from their normal feeding grounds by man's activities could be accommodated elsewhere. This short paper discusses and contrasts methods for studies of brant (Branta bernicla) in southeast England (K.C.) and wading birds (Charadrii) and shelduck (Tadorna sp.) on the Wash. Only an Abstract appears.

83. Götmark, F., and M. Åhlund. 1984. Do field observers attract nest predators and influence nesting success of common eiders? Journal of Wildlife Management 48:381-387.

The authors tested whether avian predators are attracted to islands in southern Sweden where observers flush incubating common eiders (Somateria mollissima). The abundance of hooded crows (Corvus cornix) was slightly lower after disturbance than before, although many common eider nests were exposed after disturbance. Crows did not increase their foraging effort or success in finding nests on the islands following disturbance. Herring gulls (Larus argentatus) and great black-backed gulls (L. marinus) were slightly attracted to the disturbed islands and tended to increase their foraging effort and success. Although we observed more depredations after disturbance than before, clutch size and frequency of robbed nests did not differ (P > 0.10) on disturbed and undisturbed islands. All nests were covered by the observers, and this probably protected the nests; simulated nests with exposed eggs experienced much higher predation than those covered with down.

84. Greenwood, R. J., A. B. Sargeant, D. H. Johnson, L. M. Cowardin, and T. L. Shaffer. 1982. Mallard nest success and recruitment in prairie Canada. Transactions of the North American Wildlife Natural Resources Conference 52:298-309.

Nests of mallards (Anas platyrhynchos) that were abandoned within a few days after discovery were considered to be investigator-influenced and were not used to measure survival in this paper.

85. Grieb, J. R. 1970. The shortgrass prairie Canada goose population. Wildlife Monograph 22, The Wildlife Society, Washington, D.C. 49 pp.

Prior to 1960, before harassment of birds at the Waggoner Ranch, the ranch fulfilled needs for this segment of the population. Since that time, Canada geese (Branta canadensis) have been constantly shifted about in the general area and no adequate provision has been made for their protection. Admittedly, harvest has improved under such a situation, but harvest cannot be controlled and the long-range effect on the geese may be detrimental. It would be better to keep these birds spread over their general wintering area instead of concentrating them on a single refuge area that might promote firing lines.

86. Gunn, William W. H. 1973. Environmental stress on the whistling swan. Wildfowl 24:5-7.

Tundra swans (Cygnus columbianus) are relatively undisturbed on the Mackenzie Delta, but the Delta is now a center of exploration for underlying fossil fuels. A major oil spill will be a continuous threat for years to come, and perhaps more important, human and mechanical disturbance on an unprecedented scale is a virtual certainty. There is safety in the isolation of the Arctic Coast but for one new development--the skidoo or snowmobile. The sale of skidoos is being pushed hard and Eskimos have taken to them enthusiastically. Snowmobiles make it possible to cover long distances along the coast, and tundra swans make a large and tempting target for their users.

87. Hansen, H. A., P. E. K. Shepherd, J. G. King, and W. A. Troyer. 1971. The trumpeter swan in Alaska. Wildlife Monograph 26, The Wildlife Society, Washington, D.C. 83 pp.

The Copper River study led to the conclusion that disturbance by humans during the brood season should be kept at a minimum. Both commercial and sports fishermen were frequent visitors as well as many people who traveled the road for a casual drive, photography, hiking, picnicking, hunting, target shooting, and other recreational activities. Although trumpeter swans (Cygnus buccinator) on the Copper Delta may not have been molested intentionally by the public, the varied and more frequent level of human activity seems to have had a detrimental effect in comparison to more isolated areas. A forced and rapid movement of cygnets from one body of water to another less secure, induced by human intrusion, seemed to be the most important factor causing higher mortality rates. Trumpeter swan broods exited from natal ponds when these areas were disturbed.

88. Hanson, W. C., and L. L. Eberhardt. 1971. A Columbia River Canada goose population, 1950-1970. Wildlife Monograph 28, The Wildlife Society, Washington, D.C. 61 pp.

Humans occasionally removed eggs from nests of Canada geese (Branta canadensis), broke eggs, or destroyed nest markers on lower islands 18, 19, and 20 which were open to public access. The greatest damage from man, however, was through harassment caused by picnics, beach parties, photographing nests, etc. Originally the beginning of the goose nesting season was publicized with public appeals through the news media that asked people to stay off the islands until mid-May; however, there was less destruction of nests when no publicity was used during later years of the study.

89. Hansson, L. 1966. Studies on the adaptation of the mallard (Anas platyrhynchos) to urban environments. Vår Fågelvärld Supplementum 4:95-140.

When ice forms on the river, mallards are concentrated in the holes in the ice, which in exceptionally cold weather may be reduced to two in number. Difficulties in counting do not appear until the number of mallards is approaching a thousand. The birds are exposed to some disturbances from wanderers along the river bank and also to the mallard counter. They react by disappearing only on particular occasions. During the summer there is quite a lot of traffic on the river. Especially the motor boats seem to have increased in number during recent years. Mallards living in town during summer seem to have adapted to this traffic and ignore it completely. The greatest disturbance factor consists of people wandering or skating on the ice in winter. When such a disturbance has occurred during a census, the count has been repeated later. Birds are in the habit of circling around above the river during a disturbance, and normally return soon after it is over.

90. Heitmeyer, M. E. 1985. Wintering strategies of female mallards related to dynamics of lowland hardwood wetlands in the Upper Mississippi Delta. Ph.D. Thesis, University Missouri, Columbia. 376 pp.

Mallards (Anas platyrhynchos) wintering in the Mingo Basin changed their habitat use, daily time budgets, and food habits in response to human-related disturbance. Hunting was the main disturbance, but vehicular and foot traffic were also involved. Refuge areas were especially important during hunting seasons as evidenced by concentrations of mallards on certain areas. Effects of hunting disturbance are not entirely known but potentials were outlined in an earlier study. Disturbance seems most detrimental to wintering mallards in late winter and spring.

91. Henry, W. G. 1980. Populations and behavior of black brant at Humboldt Bay, California. Masters of Science Thesis, Humboldt State University, Arcata. 111 pp.

Use of specific areas by brant (Branta bernicla) and daily flight activity were influenced by tidal level, food availability, time of day, and particularly by hunting disturbance. Areas affected by human activity were used at lower densities than areas without these disturbances. Brant reacted to open-water hunting by leaving the Bay and flying to the ocean where there was little food. Brant were particularly susceptible to disturbance by aircraft, especially helicopters. Flights below 300 m often caused flocks to move to the ocean. Denying the birds an undisturbed feeding place during the day could result in a loss of energy and a lowering of body weight at a time when they need to prepare for northward migration and breeding.

92. Heusmann, H. W., and R. G. Burrell. 1974. Park mallards. Pages 77-86 in A symposium on wildlife in an urbanizing environment. 27-29 Nov. 1973, Springfield, Mass. Massachusetts Cooperative Extension Service, Amherst, Mass. 182 pp.

The greatest source of nest and brood destruction may result from the human disturbance. During the spring of 1973, two youngsters were seen rowing around a lake collecting eggs from all the mallard (Anas platyrhynchos) nests they found. Another person reported that many times he has observed people in motorboats intentionally run down broods of ducklings and in one instance beat a number of ducklings to death with paddles. We also have received reports of ducks in parks being stoned or clubbed to death. Well-meaning people can also cause nest destruction. At Norumbega park, employees of a motel brought food daily to a nestling mallard but the nest was destroyed by a predator that may have been attracted by the scent of the food. Results of a questionnaire and interviews with people observing or feeding the ducks are included.

93. Heyland, J. D., and W. T. Munro. 1967. The use of helicopters in hunting waterfowl nests. Journal of Wildlife Management 31:200-201.

The helicopter rotor spread was 35 ft (10.7 m) but the area affected by the downdraft was 45-50 ft (13.7-15.3 m) in diameter. It was apparent that the agitation of the nesting cover caused by the downdraft, coupled with the noise of the engine, was sufficient to cause ducks to flush. In addition to being faster, cheaper, and more efficient, use of the helicopter has other advantages, such as a reduction in nest desertion due to nest hunting activities. When examined the day following the survey, none of the nests located by the helicopter crew had been abandoned. By kneeling on a pontoon to locate, examine, and mark nests without landing or leaving the hovering helicopter, no human scent is left, the vegetation does not appear disturbed, and no trails are left for predators.

94. Hochbaum, H. A. 1944. The canvasback on a prairie marsh. American Wildlife Institute, Washington, D.C. 201 pp.

When flushed from the nest during egg-laying and early-incubation periods, female canvasbacks (Aythya valisineria) invariably leave by way a lane, swimming to open water, and then flying if approached too closely. Some leave while the canoe is still a quarter mile (0.4 km) or more away. Towards the end of incubation the female sits closely, flushing directly from the nest when the intruder is a few yards away. After absences induced by disturbance, the hen may return to find her brood dispersed and may fail to retrieve them all.

95. Hochbaum, H. A., S. T. Dillon, and J. L. Howard. 1954. An experiment in the control of waterfowl depredations. Transactions of the North American Wildlife Conference 19:176-185.

The observations of the first 2 years of study at Delta, Manitoba indicate that (1) patrol of areas by a trained man helped reduce losses of unharvested grain in outlying fields, (2) a combination of gunfire and scaring devices was effective but gunfire had to persist for several evenings in wet fields and be repeated when the harvest was long delayed, (3) ducks need not be killed if scaring is to be effective.

96. Hume, R. A. 1976. Reactions of goldeneyes to boating. British Birds 69:178-179.

Other waters often have an increase in waterfowl in late winter and early spring but this was not evident at Chasewater, and in the winter of 1974-75 the totals from late January were much lower than in December, almost certainly because of the increased frequency of midweek boating. Repeated observations showed that common goldeneyes (Bucephala clangula) often fly when people on the shore approach closer than 100 or 200 m but invariably settle again elsewhere on the water. A single sailing dinghy, however, may be sufficient to cause over 60 common goldeneyes to take flight and most to leave entirely within a few minutes. Any remaining birds then fly up each time the boat approaches to within 300-400 m and generally leave within an hour. A powerboat causes virtually instantaneous flight as soon as it appears on the water, the majority of birds leaving, and, if it traverses the length of the reservoir, all the remaining birds leave within minutes.

97. Hummel, V. D. 1980. Durchzug und überwinterung der kurzschnabelgans (Anser brachyrhynchus) im bereich der Nordseeküste (1974-1977). [Migration and winter distribution of the pink-footed goose (Anser brachyrhynchus) in the coastal area of the North Sea (1974-1977)]. Die Vogelwelt 101:121-131.

Resting along the way does not last long, particularly at the time of duck hunting along the entire German coast. Hunting so disturbs the pink-footed geese that they are quickly on their way. [translated]

98. Hunt, E. G., and W. Anderson. 1966. Renesting of ducks at Mountain Meadows, Lassen County, California. California Fish and Game 52:17-27.

Desertion in the 1956 study, 29.5%, was about 10% higher than that recorded in 1954. This increase probably resulted from disturbance of normal nesting activities by nest-trapping. Nesting mallards (Anas platyrhynchos) were difficult to trap and deserted readily.

99. Jahn, L. R., and R. A. Hunt. 1964. Duck and coot ecology and management in Wisconsin. Wisconsin Conservation Department Technical Bulletin 33, Madison. 164 pp.

This bulletin reviews Zimmerman's (1953) paper where it was reported that some Wisconsin lakes bordered with homes were so heavily used for recreation in the early 1940's that breeding ducks were discouraged from utilizing otherwise suitable habitat. Human activities on and near permanent water have increased tremendously. Activities of shore residents, fishermen, and boaters seem to discourage breeding waterfowl from using otherwise adequate habitat. On aerial waterfowl censuses, many duckless lakes with excellent stands of submerged aquatic plants were seen. This is especially true on smaller (under 1,000 acres (405 ha)) lakes with numerous piers and boats. Dillon (1956:37) reported that, on the 180-acre (72.9 ha) University Bay waterfowl refuge, fall fishing influenced use of the area by waterfowl, and boats on the bay often caused considerable disturbance.

100. Jessen, R. L. 1981. Special problems with diving ducks. Paper presented to the Fourth International Waterfowl Symposium, New Orleans, Louisiana, January 31-February 1, 1981. Minnesota Department of Natural Resources, St. Paul. 8 pp.

Lesser scaup (Aythya affinis) availability for sport hunting, especially in the Upper Midwest, is influenced by wariness of the birds and their intolerance to disturbance. A largely unrecognized wariness of lesser scaup to all kinds of disturbances, especially sport hunting, reduces their use of many fall habitats in the lake region of the Upper Midwest. Development of appropriate harvest techniques could improve the take of these birds by sport hunting. Such techniques should emphasize availability of feeding and resting areas rather than enlarged seasons and bag limits.

101. Jessen, R. L., J. P. Lindmeier, and R. E. Farmes. 1964. A study of duck nesting and production as related to land use in Mahnomen County, Minnesota. Pages 26-85 in J. B. Moyle, ed. Ducks and land use in Minnesota. Minnesota Department of Conservation, Division of Game and Fish Technical Bulletin No. 8.

Mean flushing distance (feet/meters) of mallard (Anas platyrhynchos) and blue-winged teal (Anas discors) hens as related to stage of nesting and to repeated visits to the nest (adapted, sample sizes not shown).

		Stage of nesting
		Laying	Early incubation	Late
Mallard	1st visit	20/6	6/2	5/2
	2nd visit	24/2	15/5	19/6
Teal	1st visit	7/2	2/1	No data
	2nd visit	4/1	6/2	No data

The authors believed that predation is not significantly increased when reasonable care is exercised by the observer in approaching nests. Nest losses from human intrusion were due primarily to desertion by hens. Increased predation loss because of human intrusion was unimportant.

102. Joensen, A. H., and J. Madsen. 1985. Waterfowl and raptors wintering in wetlands of western Greece, 1983-85. Natura Jutlandica 21:169-200.

In the Amvrakikos wetlands studies were conducted on distribution of ducks and Eurasian coot (Fulica atra) in relation to food resources and the impact of human disturbance, especially hunting. Observations on hunting modes were made elsewhere also. The number of hunters is large, and illegal practices are frequently observed, including killing of protected species. Disturbance by hunters often causes mass displacement of ducks from the most important feeding areas. Some species such as northern shoveler (Anas clypeata), northern pintail (Anas acuta), green-winged teal (Anas crecca), and common pochard (Aythya ferina) are very sensitive to disturbance. Northern shoveler and northern pintail cease to feed when shooting occurs near them, while Eurasian wigeon (Anas penelope) and Eurasian coot are less sensitive and continue foraging at lower intensity. Shooting from motor boats is extremely disturbing. Sportsmen in only 1 or 2 powered punts in Logarou Lagoon and equivalent numbers in Koronisia Bay can disturb waterfowl so that they stop feeding and eventually abandon the area. Poled fishing punts move rather slowly and generally cause less disturbance. Motor boats generally flush waterfowl and interrupt feeding for a much longer time. In Koronisia Bay fishing boats regularly displace ducks from feeding areas.

103. Johnson, F. A., and F. Montalbano. 1984. Selection of plant communities by wintering waterfowl on Lake Okeechobee, Florida. Journal of Wildlife Management 48:174-178.

Biases associated with their method of collecting data include the possible differential visibility of ducks relative to vegetational cover. Although not quantifiable, it was believed that this bias was reduced because birds tended to flush before the aircraft.

104. Johnson, R. E. 1964. Fish and fowl. pages 453-458 in J. P. Linduska, ed. Waterfowl tomorrow. U.S. Department of Interior, Fish and Wildlife Service. U.S. Government Printing Office, Washington, D.C.

It was recognized that if waterfowl use heavily fished waters for breeding, resting, or feeding, they will be disturbed often by anglers who use boats or fish from the banks. It was suggested that this conflict can be resolved by zoning certain water areas for use by waterfowl or by anglers or by restricting fishing during the season when waterfowl are nesting and rearing their broods.

105. Jones, J. J. 1981. Potential effects of winter shipping on diving ducks wintering on the Detroit River. Masters of Natural Resources Thesis, University Michigan, Ann Arbor. 91 pp.

The author believes winter navigation, if initiated, could pose a serious threat to wintering waterfowl for three major reasons. One reason is that ice-breaking activities could cause ice to be diverted to areas that were previously ice-free during winter. Areas that are susceptible to being covered by diverted ice include important foraging sites for wintering waterfowl. This could decrease waterfowl food availability. Winter shipping may adversely affect food abundance by the resuspension of fine substrates. The coarser substrates left behind could limit important waterfowl foods. There is evidence that waterfowl wintering on the Detroit River were depleting their endogenous energy reserves even when critical shallow water depths were available for feeding. Loss of feeding habitat due to long periods of ice cover may force major portions of the population to either migrate with low lipid reserves, or starve to death.

106. Jones, R. D., Jr. 1964. Age group counts of black brant in Izembek Bay, Alaska. Wildfowl 15:147-148.

Observation points were chosen because of their being free of waterfowl hunters, hence brant (Branta bernicla) could approach the shore more closely.

107. Jones, R. D., Jr. 1973. A method for appraisal of annual reproductive success in the black brant population. Masters of Science Thesis, University Alaska, Fairbanks. 117 pp.

Brant (Branta bernicla) did not take alarm at an exposed observer, even though he moved a bit, so long as he did not stand upright. Bright yellow oilskins, regular apparel both in and out of boats in Izembek Lagoon, did not deter approaching birds. Disturbing factors, in addition to waterfowl hunters, included airplanes and avian predators.

108. Jones, R. D., Jr., and D. M. Jones. 1966. The process of family disintegration in black brant. Wildfowl 17:75-78.

Flocks of brant (Branta bernicla) family groups were easily excitable and quarrelsome. They scrambled into flight at the approach of an airplane as well as an avian predator. Later, following family group disintegration, only low flying aircraft disturbed the large amorphous flocks. In September there were no juveniles unattached to family groups. Between 23 September and 18 October, the degree of interaction in these flocks clearly increased, as did the disposition to fly at the approach of an airplane. When family breakup was complete, the population was composed of a relatively few very large flocks with all age groups represented; hostile encounters were rare and the flock was not disturbed by an approaching airplane.

109. Kalmbach, E. R. 1937. Crow-waterfowl relationships: based on preliminary studies on Canadian breeding grounds. U.S. Department of Agriculture Circular 433. 36 pp.

The author emphasized strongly that careless intrusion of humans into duck-nesting areas creates a serious hazard, for incubating ducks may then be flushed in the presence of American crows (Corvus brachyrynchos) and the suddenly uncovered eggs left exposed to view. This is the reason that breeding grounds should be carefully guarded against trespass during nesting.

110. Keith, L. B. 196l. A study of waterfowl ecology on small impoundments in southeastern Alberta. Wildlife Monograph 6, The Wildlife Society, Washington, D.C. 88 pp.

The author wrote that there has always been controversy over the effect of human intrusion on predation during nesting studies. Tracks and trails leading to nest, nest markers, disturbance of nest cover, and observation of nest-finding activity, etc., have been cited as evoking increased predation. Hammond and Forward (1956) thoroughly discussed this problem on the basis of extensive experience at the Lower Souris Refuge, and concluded that when reasonable care was exercised, these factors usually were of minor consequence. However, the author believes there is a much more serious threat to waterfowl in areas where sport fish occur, and that is the general disturbance caused by fishermen. Fishing is a popular recreation on the prairies, and available waters are heavily used. Breeding birds and their young seem to find this disruption intolerable waterfowl populations and production seem to be low under these circumstances. In Alberta this danger has recently grown as small impoundments that previously lacked fish are now being stocked with trout (Salmo spp.).

111. Knittle, C. E., and R. D. Porter. 1988. Waterfowl damage and control methods in ripening grain: an overview. Fish and Wildlife Technical Report 14, U.S. Department of Interior, Fish and Wildlife Service, Washington, D.C. 17 pp.

Many methods are available to reduce losses, but success varies. Hazing with exploders, shotguns, rifles, and pyrotechnic devices; scarecrows of many descriptions; and aircraft can all be used to haze and frighten waterfowl.

112. Korschgen, C. E., L. S. George, and W. L. Green. 1985. Disturbance of diving ducks by boaters on a migrational staging area. Wildlife Society Bulletin 13:290-296.

Disturbances of canvasbacks (Aythya valisineria) by recreational boaters were studied on the upper Mississippi River to determine frequency of disturbance and possible energetic implications. Twenty-nine random observation periods during morning (30 min before sunrise to 1200 hr) and afternoon (1200 hr to sunset) were used to determine numbers by species, their dominant activity, and distribution on the staging area. Recreational boating activity that resulted in disturbance was recorded as well as flock size and duration of response. An average of 17.2 boats/day resulted in 5.2 disturbances/day. Sport fishermen accounted for 42% of the disturbances. Mean flock size of disturbed canvasbacks was 12,474 with 4.43 minutes/disturbance. Diving ducks were estimated to have left the staging area 19 times during the fall because of human disturbance. Birds may be forced to fly up to 1 hour each day due to disturbance. Energetic costs of the disturbances are unknown, but they may be detrimental if canvasback numbers significantly increase and require more food, American wildcelery (Vallisneria americana) winter bud production significantly decreases, disturbances become more severe, or foods at other migration areas deteriorate.

113. Kramer, D. 1984. The effects of recreational activities on the winter wildfowl population at Priory Park Lake, Bedford, during the winter of 1982-83. Ardea 1983-84:34-46.

Counts of wintering wildfowl were made at a 25-ha gravel pit lake before and after sailing and sail-boarding activities; counts with and without disturbance were compared. Recreational activities on the lake were restricted to a particular zone between 1 November and 28 February 1983, leaving a disturbance-free zone; the effect of this on the behavior and distribution of waterfowl was noted. Before zoning, any sailing activities displaced nearly all waterfowl from the lake. During the first month of zoning, sailing activities still caused a significant reduction in number of birds and species present, but after this period nearly all species tolerated the presence of sail-boards and dinghies and remained on the lake in numbers similar to those present on undisturbed days. Species included Canada goose (Branta canadensis), Eurasian wigeon (Anas penelope), gadwall (Anas strepera), green-winged teal (Anas crecca), common pochard (Aythya ferina), tufted duck (Aythya fuligula), long-tailed duck (Clangula hyemalis), common goldeneye (Bucephala clangula), mallard (Anas platyrhynchos), northern shoveler (Anas clypeata), and mute swan (Cygnus olor). Results in this paper are relatively similar to those in the publication by the same author reviewed below.

114. Kramer, D. 1986. The effects of recreational activity on wintering wildfowl populations at Priory Park Lake, Bedford. Bedfordshire Naturalist 41:21-26.

A 25-ha lake was selected and a disturbance-free zone created. Two visits per day were made on 39 occasions between 18 September 1982 and 28 February 1983. Canada geese (Branta canadensis) were present only once and the flock was obviously alarmed by the first boat launched and departed immediately. Eurasian wigeon (Anas penelope) did not seem to be disturbed by the sailing. Mallard (Anas platyrhynchos) were affected by the sailing and deserted the lake. People walking, jogging, fishing, or dog walking along the lakeshore had little effect, except when a dog-owner deliberately sent a dog into the water and when the sudden movement of a person breaking into a fast run caused a party of 10 common goldeneye (Bucephala clangula) to depart from the lake. During the period before sailing was zoned a low level of disturbance resulted in near total departure of all water birds. During the pre-zoning period, some species such as the green-winged teal (Anas crecca) took flight as soon as a single sailboard or dinghy was launched, while common pochard (Aythya ferina) and tufted duck (Aythya fuligula) followed as soon as the craft approached within about 80 m of the flocks. Common pochard and tufted duck continued to be disturbed by sailing for several weeks (5 weeks in the case of common pochard) after the refuge was zoned. Thus learning probably took place.

115. Kramer, G. W., L. R. Rauen, and S. W. Harris. 1979. Populations, hunting mortality and habitat use of black brant at San Quintin Bay, Baja California, Mexico. Pages 242-254 in R. L. Jarvis and J. C. Bartonek, eds. Proceedings of the Symposium on Management and Biology of Pacific Flyway Geese, Northwest Section, The Wildlife Society, Washington, D.C.

Use of specific areas of the bay by brant (Branta bernicla) and daily flight activities were influenced particularly by hunting disturbance. On days without hunting, brant left deep-water areas and flew to eelgrass beds. Brant normally did not fly at other times except when disturbed by aircraft, fishermen, or boaters. Disturbance by hunters resulted in flight activity five to six times greater than on corresponding non-hunt days. Flights were more frequent, occurred sooner after hunting began and involved more birds during the 16 January-28 February 1975 portion of the hunting season (spring migration) than earlier. The intensity of movement to the ocean was significantly related to the level of human disturbance. Aircraft always caused most brant to take flight and remain airborne until the aircraft passed, but only a small portion of the ducks and shorebirds reacted. The authors believe that brant might abandon San Quintin Bay as a migration area as they left Humboldt Bay. They recommended stricter law enforcement; making herding illegal; continuing rest days during the hunt on Monday, Tuesday, and Wednesday; reducing the bag limit; establishing a refuge area; and avoiding ecological changes which would affect eelgrass.

116. Krasowski, T. P., and T. D. Nudds. 1986. Microhabitat structure of nest sites and nesting success of diving ducks. Journal of Wildlife Management 50:203-208.

To minimize investigator-associated nest failure, nests were revisited once after hatch was expected. Nests believed to be influenced by investigator disturbance were excluded from analyses that compared habitat structure with nest success. Nest success was not independent of the time of nest location ( = 4.08, df = 1). Nests found early in the laying stage failed more often than those found later. Thus, the nest visit may have contributed to nest failure.

117. Krohn, W. B., and E. G. Bizeau. 1980. The Rocky Mountain population of the western Canada goose: its distribution, habitats, and management. Special Science Report--Wildlife No. 229. U.S. Department of Interior, Fish and Wildlife Service. 57 pp.

Data are presented that show desertion and destruction, no matter what the underlying cause, account for most nest losses of Canada geese (Branta canadensis). This has important management implications, since desertion can be minimized in areas with much human activity by regulating fishing seasons and access during the nesting season. A net gain in goslings hatched was recorded from elevated structures and these biologists concluded that structures were a positive management technique, provided they were maintained annually and located in areas away from people. The authors recommended that to more closely control the harvest of Canada geese from individual breeding regions, managers should consider encouraging Canada geese to molt within the region where they hatched. This could be accomplished by restricting recreational use and banding on lakes and reservoirs used by molters during July and August. A lack of disturbance seems especially critical to molters that are just starting to use an area.

118. Laperle, M. 1974. Effects of water level fluctuation on duck breeding success. Pages 18-30 in H. Boyd, ed. Canadian Wildlife Service waterfowl studies in eastern Canada, 1969-73. Report Series No. 29. Canadian Wildlife Service.

Searching effort was reduced from 1968 to 1970, which meant a reduction of interference by observers, but the American black duck's (Anas rubripes) nesting success fell from 64% in 1968 to 53% in 1969 and 44% in 1970. There was no such trend for the mallard (Anas platyrhynchos) with nesting successes of 36%, 73%, and 61% for the same years. The low in 1968 was attributed to the intensive effort made that year to capture mallard hens on nests.

119. Lebeda, C. S., and J. T. Ratti. 1983. Reproductive biology of Vancouver Canada geese on Admiralty Island. Journal of Wildlife Management 47:297-306.

A molting flock of approximately 300 Canada geese (Branta canadensis) at Fools Inlet was monitored weekly. Flightless Canada geese on water or in the intertidal zone fled into the forest when approached by observers in a boat. Similar behavior by flightless Vancouver Canada geese was observed in Adams Inlet in 1973 by Ratti et al. (1977). The authors recommended that human disturbance on Admiralty Island should be monitored and limited in some areas. Tiedeman Island (an island in the Admiralty Island complex) has an important concentration of breeding Canada geese and should also be considered in any management plan that would deal with the impact of human recreation. Known molting sites, such as Fools Inlet and Adams Inlet should be protected from human disturbance during the molting period; elsewhere human disturbance resulted in desertion by molting Canada geese (Sterling and Dzubin 1967).

120. Lee, F. B., R. L. Jessen, N. J. Ordal, R. I. Benson, J. P. Lindmeier, R. E. Farmes, and M. M. Nelson. 1964. Ducks and land use in Minnesota. Minnesota Department of Conservation Technical Bulletin 8. 140 pp.

In the Mahnomen Area 9% of the nests found were deserted by hens. Similar figures for Otter Tail and Pope Areas are 8% and 12%. Some desertion can be attributed to rope-dragging of nesting areas and to nest visits by study personnel.

121. Liddle, M. J., and H. R. A. Scorgie. 1980. The effects of recreation on freshwater plants and animals: a review. Biological Conservation 17:183-206.

This paper reviews the impacts of recreation on freshwater plants and animals, making a distinction between water- and shore-based activities, and between physical and chemical effects. Impacts of water-based recreation resulting mainly from boating, are discussed in terms of wash, turbulence and turbidity, propeller action, direct contact, disturbance to animals, and pollution from outboard motors and sewage. Impacts resulting from shore-based activities, such as angling and swimming, include trampling and associated effects, as well as sewage and other chemical impacts. Management for recreation is also considered. There is relatively more information on the effect of recreational activities on plants than on animals, but the authors consider that further research is required in both fields. Some possible approaches are presented. This review is extensive in the whole, and so is the section on disturbance.

122. Loosjes, M. 1974. Over terreingebruik, verstoringen en voedsel van grauwe gansen Anser anser in een brak getijden-gebied (Habitat use, disturbances and food of greylag geese Anser anser in a brackish tidal area). Limosa 47:121-143.

Greylag geese sleep principally in a dry rush-area, however, often on mudflats because of disturbance. Voluntary dispersal within the Beninger Slikken generally did not have a fixed pattern. Greylag geese fled from disturbance to mudflats or adjoining water. In the event of a serious disturbance, they fled to mudflats. Hunting and planes are disturbing factors. During day-time greylag geese are disturbed an average of one-third of the time, and they have to flee four times a day. In stormy weather with high tide, greylag geese flee to grassland outside the dikes. Recent damming up of the estuary in autumn 1970 will be harmful because of fresh water, probably increased pollution, ceasing of tides, and increase of disturbance. Other threats are increase of recreation, industrialization and aerial traffic, and a decrease of refuge.

123. MacInnes, C. D. 1962. Nesting of small Canada geese near Eskimo Point, Northwest Territories. Journal of Wildlife Management 26:247-256.

On one occasion 16 parasitic jaegers (Stercorarius parasiticus) landed at a single snow goose (Chen caerulescens) nest within 30 seconds of the departure of the incubating female. The extent of parasitic jaeger predation was much increased by disturbance in the nesting area of Canada geese (Branta canadensis), particularly by the presence of a man. In 1959 it was not unusual to count 30 or 40 jaegers within 100 yd (91.4 m) of a man in the blue goose colony.

124. MacInnes, C. D. 1980. Comment: observer-induced predation is real. Journal of Wildlife Management 44:222-224.

This article is a response to Strang's questioning (see paper 182) of parasitic jaeger (Stercorarius parasiticus) predation induced by the observer. MacInnes defended his position and suggested that predator density at Strang's study area may have been less, and he agreed that further work needed to be done to define observer-induced losses of waterfowl nests. See Strang in the same volume on the pages immediately preceding this article (Journal of Wildlife Management 44:220-222), which is referenced herein.

125. MacInnes, C. D., and R. K. Misra. 1972. Predation on Canada goose nests at McConnell River, Northwest Territories. Journal of Wildlife Management 36:414-422.

Predation losses from nests of small Canada geese (Branta canadensis) were observed from 1965 to 1969 on a 62-km² study area at the mouth of the McConnell River, Northwest Territories. The lack of significant regression of logarithm of clutch size at first observation on date caused the author to believe that partial loss of a clutch did not occur in the absence of disturbance by humans. Partial clutch losses comprised 55% of all eggs observed lost after repeated visits to individual nests. The proportion of nests completely destroyed did not vary among years, but the proportion losing some eggs did change significantly. The latter difference was due to changes in predator activity, or of their