Northern Prairie Wildlife Research Center
In the following annotated list, the taxonomic order follows that of the American Ornithologists' Union (1957) check-list. Current accepted nomenclature follows the check-list, as amended (American Ornithologists' Union 1973, 1976). The status of 121 species that have been recorded on our study area is briefly summarized. Maximum counts, dates of observations, limited data on clutch or brood size, population estimates for species not represented in Table 2, and habitat occupancy are included. All dates are 1981 unless otherwise indicated. Terms used to describe relative abundance of individual species (e.g., common, uncommon, etc.) follow the definitions in Faanes (1981).
One migrant was observed on the Pembina River on 16 April (S. Young, personal communication).
A single bird was observed on 16 September along the Pembina River between the Vang Bridge and the Canadian border (S. Young, personal communication).
Single birds were regularly observed foraging along the banks of the Pembina River during the breeding season. There are no known nesting rookeries in the study area. Large amounts of lowland forest suitable for supporting a rookery exist downstream from Walhalla. Seven great blue herons were observed along the river on 15 September and a single bird 16 September (S. Young, personal communication).
We flushed one bird from the bank of the Little North Pembina River on 30 June. A single bird was observed along the Pembina River on 16 September (S. Young, personal communication).
Four flocks totaling about 400 birds were seen 15 April and one flock of about 70 was seen 16 April. A migrant flock of 31 snow geese was seen 15 September and another of unspecified size was observed 16 September (S. Young, personal communication).
Fairly common nesting species along the Pembina River. A breeding waterfowl pair census conducted by canoe 5-6 May revealed a mean of 1.19 mallard pairs per km of river. The breeding population was estimated at 48 pairs. About 56% of these breeding pairs were observed in the reach of river from the Canadian border to the Vang Bridge. About 27 mallards were found along the Pembina River 15 September (S. Young, personal communication).
Uncommon nesting species along the Pembina River. A breeding waterfowl pair census conducted by canoe 5-6 May revealed a mean density of 0.27 pair per km of river. The breeding population was estimated at 11 pairs.
One pair was observed on a beaver impoundment adjacent to the Pembina River on 15 April (S. Young, personal communication).
Uncommon and local nesting species along the Pembina River. A waterfowl pair census conducted by canoe 5-6 May revealed a mean density of 0.32 pair per km of river. The breeding population was estimated at 13 pairs. Three groups of wood ducks totaling 33 individuals were observed on the Pembina River on 15 September and 4 were observed 16 September.
Common Merganser (Mergus merganser)One pair was observed on the Pembina River on 16 April (S. Young, personal communication).
One pair was found on the Pembina River about 3.2 km downstream from the Canadian border on 8 June.
One pair was observed 28 May flying over a bur oak-green ash forest in Section 33, T. 163 N., R. 58 W. S. Young (personal communication) reported two migrant sharp-shinned hawks on 15 September and single birds on 16 and 17 September.
Uncommon and local nesting species throughout the study area. The largest number observed was four on 28 May. The study area breeding population was estimated at eight pairs. During the nesting season, adult Cooper's hawks were consistently observed in five areas that probably represented territories which were associated with the open stands of mixed bur oak-green ash forest.
Fairly common and regularly observed nesting species. Three active nests were found 22 June. These nests were located in Sections 5, 9, and 10, T. 163 N., R. 58 W. (S. Young, personal communication). The total nesting population for the study area was estimated at 10 pairs. Most nesting pairs were associated with open bur oak-green ash forest. During fall migration, 64 red-tailed hawks were observed 15-17 September.
Uncommon nesting species most frequently observed in large expanses of mixed bur oak-quaking aspen forest. The total breeding population was estimated at 10 pairs. Seven migrant broad-winged hawks were observed 15-16 September.
Apparently occurs only as a migrant and occasional summer visitor. A single individual was observed on the study area 8 and 11 June. Three migrant Swainson's hawks were observed 16-17 September. Stewart (1975) considered this hawk rare and local on the Agassiz Lake Plain, but fairly common in other regions.
A single migrant was observed over the Pembina River gorge on 15 September (S. Young, personal communication).
A single migrant was observed over the Pembina River gorge on 15 September (S. Young, personal communication).
Rare summer resident, most commonly observed hunting over crop fields on the study area. Three males and one female were regularly seen over various fields in the area from Vang Bridge downstream to the proposed dam site. Probably only one pair nested on the study area.
One adult was observed flying downstream along the Pembina River on 7 June. Salt and Salt (1976) showed that the nearest nesting area in Manitoba was in the lake region near Winnipeg. Green and Janssen (1975) showed the nearest known osprey nesting area in Minnesota as Lake of the Woods County about 225 km east. Stewart (1975) reported a 17 June 1972 observation of an osprey in Walsh County, North Dakota. There is one known nest record for North Dakota.
A single peregrine falcon, probably a female, was observed along the Little North Pembina River in Section 35, T. 163 N., R. 58 W., on 8 September (C. Faanes, personal observation).
Rare and local during summer; probably three pairs nested on the study area. Two pairs were regularly observed in bur oak forest edge near Vang Bridge and along the Little North Pembina River. A third pair was frequently observed at the edge of a bur oak-quaking aspen forest about 1 km downstream from the Canadian border.
Nesting species fairly common and well-distributed throughout the study area. The breeding population was estimated at 126 pairs. During June, six broods averaging 7.5 young per brood were observed. Virtually all mature forest types were occupied by ruffed grouse. Largest breeding densities occurred in mixed quaking aspen-bur oak forest.
One was heard near the proposed dam site on 4 May (S. Young, personal communication).
Uncommon and local nesting species in the area downstream from Vang Bridge. Total breeding population was estimated at 10 pairs. An adult with a brood of 11 was seen near the Vang Bridge 16 June. Most gray partridge were observed near the edge of various crop fields adjacent to the Pembina River.
Uncommon but an increasing resident throughout the area. The North Dakota Game and Fish Department estimated 250 wild turkeys in 1981. One nest containing 12 eggs was found 14 April in Section 1, T. 162 N., R. 57 W. (S. Young, personal observation). Most observations of adults during the breeding season were in mixed quaking aspen-bur oak forest. Wild turkeys were first released by the North Dakota Game and Fish Department on 15 January 1979. This release, including 5 males and 21 females, was made in Section 30, T. 164 N., R. 58 W. Subsequent releases were made within the Pembina Hills in 1980 and 1981. The 1980 release included 7 males and 22 females in Section 10, T. 162 N., R. 57 W. The 1981 effort included 17 males and 28 females, released about 19 km south of the 1980 site.
Migrant flocks of 50 and 35 sandhill cranes were observed over the Pembina River on 15 and 16 September, respectively (S. Young, personal observation).
Three individuals were observed on the Pembina River on 4 May (S. Young, personal communication).
Uncommon and local nesting species restricted primarily to the area downstream from Vang Bridge. Breeding population was estimated at 15 pairs. Most nesting pairs were associated with fallow fields or sandbars on the Pembina River.
One adult was heard and then seen flying over a crop field near the proposed dam site on 16 June.
Two greater yellowlegs were seen on a sandbar upstream from the Vang Bridge on 20 July.
Uncommon nesting species restricted to sandbars within the channel of the Pembina River. One nest containing three eggs was found on 28 May in Section 30, T. 164 N., R. 58 W. The total breeding population was estimated at 12 pairs.
An adult male was captured and banded on 16 June. The habitat occupied by this bird was young bur oak forest located in Section 18, T. 164 N., R. 58 W. Stewart (1975) considered this species a hypothetical breeder in North Dakota. J. Piehl (personal communication) reported the first North Dakota nest record from Ransom County in 1979. Our observation was the first breeding season record for Cavalier County and the 11th for North Dakota. Six of the 11 nesting season records have been from northeastern North Dakota.
One bird was flushed from the bank of the Pembina River on 3 September.
A flock of seven ring-billed gulls was observed resting on a plowed field on 22 April.
Flocks of 5-20 Franklin's gulls were observed daily during June as they foraged over agricultural fields from Vang Bridge downstream to the proposed dam site. Stewart (1975) recorded one probable nesting colony in Cavalier County. The nearest known colony is about 80 km southwest of the study area on Sweetwater Lake, Ramsey County.
One flock of eight rock doves was seen near a farmstead in Section 20, T. 163 N., R. 57 W., on 16 June. No other population data were collected.
Fairly common nesting species occurring in virtually all wooded habitats. Highest breeding densities occurred in quaking aspen forest. Five nests were found.
Two yellow-billed cuckoos were recorded on 20 July from a bur oak forest in Section 33, T. 163 N., R. 57 W. Stewart (1975) considered the yellow-billed cuckoo a hypothetical nesting species in North Dakota, citing about 10 observations from southeastern or western regions of the State. Recent field work in northeastern North Dakota has revealed several nesting season records, including one along the Turtle River, Grand Forks County, on 15 July 1979.
Fairly common nesting species apparently reaching highest breeding density in mixed bur oak-quaking aspen forest. The study area population was estimated at 71 pairs.
Probably a fairly common nesting species throughout the study area. S. Young (personal communication) reported five active nests; three of them contained a total of seven young during June 1981. Most breeding-season adults were observed at the periphery of bur oak-green ash forests. The breeding population was estimated at 10 pairs.
Fairly common nesting species throughout the study area. Highest breeding densities were associated with bur oak forest. Two nests were found within 50 m of each other on 20 July.
Rare and local nesting species restricted primarily to the banks of the Pembina River. Adults were regularly observed foraging along open reaches of the river downstream from the Vang Bridge. This area contained many open hillsides with substrate suitable for nest placement. The study area population was estimated at five pairs.
Uncommon and local nesting species occurring primarily in open stands of bur oak forest. The breeding population was estimated at 20 pairs.
Probably a rare nesting species in the study area. R. Stewart (personal communication) found one on 30 June 1962, in T. 164 N., R. 58 W.
Fairly common nesting species throughout the study area.The breeding population was estimated at 82 pairs. Largest breeding densities occurred in quaking aspen forest. One nest was found.
Uncommon nesting species throughout the study area; most frequently observed in mixed bur oak forest. The breeding population was estimated at 15 pairs. Conner et al. (1975) reported that the hairy woodpecker occupied a range of forest types from sparse stands with low basal area to mature forest with high basal area.
Fairly common nesting species occupying most forested habitats. Largest breeding densities were associated with mixed quaking aspen-green ash forest. Conner at al. (1975) reported highest densities in sparse forest stands with low basal area. Conner and Adkisson (1977) found that the downy woodpecker primarily occupied forest edge. The breeding population in the study area was estimated at 157 pairs.
Uncommon nesting species occurring primarily along the edge of forested habitats and agricultural fields and remnant grasslands. The breeding population was estimated at 733 pairs.
Fairly common nesting species reaching highest densities in mature quaking aspen forest. Beals (1960) in Wisconsin, reported highest densities from dense forest, and Johnston (1947) in Illinois, found great crested flycatchers nesting in the forest interior. We found an active nesting cavity on 16 June, and on 30 June three young were observed foraging with adults in nearby quaking aspen forest. The breeding population was estimated at 1,178 pairs.
Uncommon and local nesting species primarily occurring along and adjacent to the Pembina River and its major tributaries. Three active nests were found beneath highway bridges. Faanes (1980) and others have shown the importance of highway bridges for nest placement. Two pairs were found nesting in more traditional sites, beneath overturned tree roots along streambanks. The breeding population was estimated at 438 pairs.
Common nesting species in peach-leaf willow thickets along the Pembina River. The breeding range of this species in North Dakota is restricted to the upper Pembina River Valley and the Turtle Mountains. Two recently fledged young were observed with adults in a willow thicket in Section 19, T. 163 N., R. 57 W., on 21 July, thus establishing the first nesting record for North Dakota. Similar habitat is used by breeding alder flycatchers in Michigan (Berger and Parmalee 1952) and in New York (Stein 1958). In the St. Croix River Valley of Wisconsin and Minnesota, preferred habitat is alder thickets, where speckled alder (Alnus rugosa) is predominant (Faanes 1981).
Common nesting species occupying virtually all habitats studied. Stewart (1975) also considered the least flycatcher common in the Pembina Hills region. Highest densities occurred in mature quaking aspen forest where the mean breeding density was 131 pairs/km². Holcomb (1972) reported densities of 148 pairs/km² in upland oak forest with sparse to moderate ground cover.
Fairly common nesting species throughout the study area. Most numerous in mature quaking aspen forest where the mean density was 375 pairs/km². The breeding population was estimated at 106 pairs. Beals (1960) reported highest densities of this species in mature forest and Bond (1957) reported that mature xeric deciduous forest supported highest breeding densities in Wisconsin.
Uncommon and local nesting species within the study area. Restricted in distribution primarily to recently planted agricultural fields or fallow fields, downstream from Vang Bridge. Stewart (1975) considered the horned lark the primary breeding bird species of North Dakota cropland. The breeding population in the study area was estimated at 50 pairs.
Uncommon summer resident. During June, adult tree swallows were frequently observed foraging over the Pembina River and adjacent croplands. Although we collected no population data on this species, or observed any nests, it undoubtedly nested in the study area. The presence of numerous natural cavities in vegetation adjacent to the river suggests that suitable nesting habitat existed.
Uncommon and local nesting species. Most breeding pairs were observed below Vang Bridge where the exposed slopes of bluffs along the river provided suitable nest site habitat. The breeding population was estimated at 15 pairs.
Uncommon summer resident occurring primarily downstream from Vang Bridge. Foraging adults were occasionally observed along the Pembina River in the heavily forested reaches near the Canadian border. Although no nests were found, this species probably nested in the study area. The presence of suitable bluff faces along the lower reaches of the river suggested that suitable nesting habitat existed there.
Fairly common nesting species occurring primarily downstream from Vang Bridge. Most adults were observed foraging over open agricultural fields or near farm buildings. Nests were found beneath both Pembina River bridges and over the Little North Pembina River.
Uncommon summer resident occurring primarily in areas adjacent to the Pembina River. Two nests found beneath the Vang Bridge were the only evidence of nesting obtained. The breeding population was estimated at 10 pairs.
Fairly common nesting species. Largest breeding densities were recorded in mixed bur oak-quaking aspen forest. The breeding population was estimated at 139 pairs. Anderson and Shugart (1974) described blue jay nesting habitat in Tennessee as deciduous forest with dense understory and a well-developed canopy.
Apparently a fairly common winter resident and migrant; rare and local during the nesting season. The breeding population was estimated at two pairs. During the nesting season, adults were observed primarily in mature lowland forest.
Two common ravens were observed at the edge of a quaking aspen forest in Section 13, T. 163 N., R. 58 W. This species was extirpated from North Dakota as a breeding bird in the late 1800's. Stewart (1975) considered recent observations of common ravens in northeastern North Dakota as representative of non-breeding vagrants.
Fairly common nesting species throughout the study area. Largest breeding densities were associated with mixed quaking aspen-bur oak forest. The breeding population was estimated at 94 pairs.
Fairly common nesting species of mature forests. Largest breeding densities were associated with willow shrub and mature quaking aspen forest. Odum (1941) reported that black-capped chickadees occupy a wide range of habitats including second-growth deciduous forest, intermediate seral stages, mature hardwood forest, advanced seral stages, and conifer groves. Two nests containing young were found in bur oak forest 25 May and free-flying young were observed in mid-June.
Fairly common permanent resident. Largest breeding densities were recorded in mature quaking aspen forest and in lowland forest. The study area breeding population was estimated at 243 breeding pairs. Anderson and Shugart (1974) described white-breasted nuthatch habitat in east Tennessee as deciduous forest with sparse understory. Stewart (1975) reported that optimum breeding habitat for this species in North Dakota included deciduous upland forest, floodplain forest, and east- or north-facing slopes of river bluffs or escarpments.
Probably a fairly common spring and fall migrant. Four were observed in mixed quaking aspen-bur oak forest on 22 April.
Uncommon and local nesting species. Largest breeding densities (76.9 pairs/km²) were recorded in mature lowland deciduous forest. The study area population was estimated at 148 breeding pairs. Stewart (1975) described house wren breeding habitat in North Dakota as upland and floodplain deciduous woodland, lakeshore forest, and east- or north-facing slopes of river bluffs or escarpments.
Common nesting species throughout the study area occupying all forest habitats investigated. Largest densities were recorded in the willow shrub community (250 pairs/km²) and lowland forest (107 pairs/km²) . Nickell (1965) found that gray catbird breeding habitat on several study areas in the eastern Great Lakes region included fencerows, dense edge, and shrubby areas near watercourses. In North Dakota, Stewart (1975) described the gray catbird as characteristic of dense thickets of small trees and shrubs that occur in moist situations.
Rare nesting species on the study area. The study area population was estimated at 12 pairs. Stewart (1975) considered this species common as a nesting bird on the Agassiz Lake Plain, and locally common on the Northeastern Drift Plain. Breeding American robins in the Pembina River gorge were restricted primarily to lowland and quaking aspen forests.
A male was heard singing 21 July in mixed bur oak-green ash forest in Section 32, T. 164 N., R. 58 W. This represented the sixth breeding season record of wood thrush in North Dakota (Lambeth and Lambeth 1979).
A single Swainson's thrush was observed in mixed bur oak-green ash forest on 8 September.
Common nesting species occupying virtually all forest habitats investigated. Stewart (1975) considered the veery abundant in the Pembina Hills. The largest mean densities were recorded in willow shrub (130 pairs/km²) and lowland forest (126 pairs/km²). Kendeigh (1945) reported largest densities from late shrub-early tree stage forest in New York. Important characteristics of veery habitat in Connecticut included moist ground, proximity to water, thickets of relatively early successional forest, and high understory cover (Bertin 1977).
Fairly common migrant; one summer record. During late April, migrant groups of three to five individuals were regularly encountered in most forested habitats. Similar numbers of fall migrant ruby-crowned kinglets were found 8 September. One singing male was recorded on a lowland forest census plot on 7 June; there were no subsequent observations. This probably represented a very late migrant rather than a summer resident.
Common nesting species throughout the study area. Largest mean breeding densities were recorded in willow shrub (49.9 pairs/km²), lowland forest (45 pairs/km²), and bur oak-green ash forest (40.2 pairs/km²). Stewart (1975) considered the cedar waxwing in North Dakota a characteristic breeding bird of semi-open deciduous woodlands including lowland woods on river floodplains and upland woods on river bluffs, hills, and escarpments.
Uncommon nesting species occurring only in mature bur oak-green ash forest. Mean breeding density in that habitat was 6.5 pairs/km². Bond (1957) reported that open deciduous forest supported the most breeding yellow-throated vireos on his Wisconsin study area. Stewart (1975) characterized North Dakota breeding habitat of this species as mature deciduous forest. The population on the study area was estimated at 284 breeding pairs.
Rare summer resident; the population was estimated at seven pairs. In addition to those observed on the study area, one male was regularly encountered in a black ash forest about 16 km southeast of Walhalla, Pembina County. Stewart (1975) did not mention this vireo as a nesting species in North Dakota. The range provided in Salt and Salt (1976) suggests that solitary vireos occur during the breeding season throughout southeastern Manitoba, including the region near the North Dakota border. Green and Janssen (1975) show that the Minnesota breeding range of this species includes only the coniferous forest zone of the State. Green and Janssen stated that the western boundary of solitary vireo in Minnesota reaches Itasca State Park, about 220 km southeast of the Pembina River study area. Assuming that the Pembina River population is viable and reproducing, its existence there is unique. Salt and Salt (1976) described nesting habitat of this species in the Canadian prairie provinces as a "mixture of evergreen and deciduous trees with a loose understory of shrubs and bushes. The borders of muskegs often provide this type of habitat."
Common nesting species occupying virtually all forest habitats investigated. Greatest breeding densities were found in lowland forest (100 pairs/km²) and in bur oak forest (62.5 pairs/km²). James (1976) reported greatest densities of red-eyed vireos in closed canopy deciduous forest with abundant understory in southern Ontario. In Wisconsin, Bond (1957) found that breeding habitat included climax mesic deciduous forest.
Uncommon nesting species. Stewart (1975) stated that the breeding range of this species included only the Turtle Mountains of Bottineau and Rollette counties, and the deltaic sand area of western Pembina County. Thus, our observations establish the Pembina River gorge as one of three known breeding areas in North Dakota. The population was estimated at 71 breeding pairs; all were associated with mature quaking aspen forest. One pair was observed copulating on 7 June.
Fairly common nesting species throughout the study area. Greatest breeding densities were associated with lowland forest (165 pairs/km²) and willow shrub (77 pairs/km²). Stewart (1975) described North Dakota breeding habitat of this species as open stands of floodplain and upland forest containing aspen, cottonwood, and elm. In southern Ontario, James (1976) found that open parkland forest was used by the red-eyed vireo.
Fairly common nesting species restricted primarily to drier upland forest habitats. Largest breeding densities were recorded in mature quaking aspen forest (50 pairs/km²) . The breeding population was estimated at 890 pairs. Stewart (1975) considered the black-and-white warbler in North Dakota a characteristic species of semi-open stands of upland forest composed of immature and second-growth trees. Kendeigh (1945) reported similar habitat use by this species in New York, although Beals (1960) found black-and-white warblers primarily in sugar maple (Acer saccharum) forests supporting a dense deciduous understory in Wisconsin.
One singing male was observed at the edge of a second-growth bur oak forest in Section 18, T. 163 N., R. 57 W., on 7 June. A pair was seen there on 17 June and on 30 June the female was observed feeding two recently fledged young. This established the first breeding record of the golden-winged warbler in North Dakota. Godfrey (1966) reported that its nesting range in Canada included extreme southern Ontario and the region near Vivian in southern Manitoba. Green and Janssen (1975) reported that golden-winged warblers occur regularly during the nesting season in Minnesota, north to Itasca State Park, Clearwater County. That location is about 220 km southeast of the Pembina River gorge. The habitat used by the nesting pair we observed was similar to that occupied in the normal breeding range. Ficken and Ficken (1968) reported golden-winged warblers in abandoned fields with shrubs and small trees less than 6 m high. Faanes (1981) reported that characteristic nesting habitat in the St. Croix River Valley of Minnesota and Wisconsin included second-growth deciduous forest in early developmental stages.
Probably a common spring and fall migrant. We observed this species regularly in bur oak-green ash, quaking aspen, and lowland forests during mid-May. Eight were observed in quaking aspen forest on 8 September.
Rare summer resident. Stewart (1975) considered this a hypothetical nesting species in North Dakota based on intermittent observations of three or four singing males in the Pembina River gorge during 1962-71, and a specimen collected in the Turtle Mountains in 1902. Stewart's observations were restricted to SW 1/4, Section 29, T. 164 N., R. 58 W. This location is about 0.8 km south of the Canadian border.
During the 1981 nesting season, we observed or heard 15 singing males in 14 scattered locations in the study area. Although the orange-crowned warbler is not considered a nesting species, Green and Janssen (1975) reported four breeding season records from Minnesota, two from the northwest region of the State. Salt and Salt (1976) reported that nesting in Manitoba occurs south of the edge of the prairies. Thus, the Pembina Hills population probably includes the southern limit of the Canadian breeding population.
An abundant nesting species that occupied all forest habitats investigated. The largest breeding density was recorded in the willow shrub community (654 pairs/km²). This was nearly 2.6 times greater than the lowland forest, which supported the second highest density (250 pairs/km²). Stewart (1975) described typical yellow warbler nesting habitat in North Dakota as thickets of small deciduous trees or shrubs on moist soils. Ficken and Ficken (1966) reported that greatest breeding densities in their New York study area were associated with shrubby vegetation.
An immature male was seen in a bur oak forest on 8 September. More intensive observations during normal migration periods should show this species as a fairly common migrant.
The yellow-rumped warbler was recorded regularly in all major forest habitats during late April, and two were still present 17 May. Six fall migrants were recorded 8 September.
Rare and local nesting species restricted to early successional stages of young bur oak forest and serviceberry thickets. The breeding population was estimated at 56 breeding pairs. Stewart (1975) reported that this species occurs in North Dakota during the breeding season only in the Turtle Mountains of Bottineau and Rollette counties, and in the Pembina Hills.
Probably an uncommon migrant. Three individuals were observed 17 May in willow shrub habitat along the Pembina River, and two were seen in similar habitat on 8 September.
Rare and local nesting species within the study area. Stewart (1975) considered the ovenbird uncommon throughout the Pembina Hills and in the deltaic sand area of western Pembina County. Although none were recorded on census plots, we estimate the population at 25 pairs, based on extensive observations throughout the area. Most breeding pairs were encountered in mesic quaking aspen forests, especially on north-facing slopes. These situations were similar to the mature forests with dense understory described by Beals (1960) for the ovenbird in northern Wisconsin.
Fairly common nesting species usually associated with early seral stage communities on wet soils. Greatest breeding densities occurred in the willow shrub community (115 pairs/km²). Occasional pairs were also encountered in wet areas of quaking aspen forest. Faanes (1981) reported that primary habitat use included alder thickets and northern sedge meadows that are becoming invaded with various shrubs including dogwood in the St. Croix River Valley of Minnesota and Wisconsin. The study area population was estimated at 287 breeding pairs.
Fairly common nesting species of mesic upland habitats. Largest breeding densities were found in early seral stage bur oak (22.7 pairs/km²) and in quaking aspen (25 pairs/km²) forests. The breeding population was estimated at 566 pairs. Cox (1960) reported that nesting habitat in northern Michigan included deciduous or coniferous forests with partially open canopy, and the presence of herbs and shrubs in the ground layer. In North Dakota, the mourning warbler is restricted as a nesting species to the Turtle Mountains and the Pembina Hills (Stewart 1975).
Common nesting species reaching maximum breeding densities in early seral stage deciduous habitats. Largest densities were recorded in serviceberry thickets (250 pairs/km²) and in the willow shrub community (211 pairs/km²). The lowest density (2.5 pairs/km²) was recorded in lowland forest. Stewart (1953) reported that largest densities of common yellowthroats on his Michigan study area were associated with dense shrubs and small trees growing on wet soils.
Probably an uncommon migrant. Single birds were observed in serviceberry thickets on 17 May and 8 September.
One pair was observed regularly throughout the breeding season in Section 32, T. 164 N., R. 58 W. The habitat occupied by this pair was the brushy ecotone between a bur oak and quaking aspen forest. Both Beals (1960) and Faanes (1981) reported similar habitat use in Wisconsin and Minnesota.
Our observations of this pair are the first breeding season records of the Canada warbler in North Dakota since 1917 (Stewart 1975). Green and Janssen (1975) reported that Canada warblers have nested in Minnesota as far west as Itasca State Park, Clearwater County. Godfrey (1966) showed that the breeding range in Manitoba included the extreme southeastern corner of that Province. Thus, if a viable breeding population of Canada warblers exists in the study area, it probably represents an overlooked extension of the main Canadian population.
Common nesting species of dry upland forest habitats. This was the second most abundant breeding bird on the study area. Stewart (1975) considered the American redstart fairly common throughout the Pembina Hills region. The largest breeding density was recorded in mature bur oak forest (180 pairs/km²) . Kendeigh (1945) reported largest densities from open, second-growth deciduous forest. Stewart (1975) described North Dakota habitats used by this bird as floodplain or upland mesophytic deciduous forest, particularly second-growth stands.
Fairly common nesting species associated with active and abandoned farmsites. No population data were gathered.
Three singing males were recorded throughout the nesting season in an alfalfa field near the proposed dam site. No other population data were recorded from the study area. This species was common in seeded grasslands and other similar vegetation away from the Pembina River gorge.
Rare and local within the study area, although common and well-distributed in seeded grasslands and cropland away from the Pembina River gorge. Based on observations throughout the study area, the breeding population was estimated at 15 territorial males.
Uncommon and local nesting species throughout the study area. The study area population was estimated at 284 territorial males. Breeding pairs on census plots were recorded only in the willow shrub community. Scattered pairs were also found associated with cattail (Typha sp.) vegetation along the periphery of small woodland ponds throughout the upper reaches of the gorge. Four nests, each containing four eggs, were found during June.
Uncommon nesting species restricted to quaking aspen forests where the mean density was 25 pairs/km². The study area population was estimated at 142 pairs. Stewart (1975) stated that the primary breeding habitat in North Dakota included wooded stream valleys and upland forests on prominent hills and escarpments. Bond (1957) reported that largest densities in southern Wisconsin were associated with early-age forests.
Not recorded as a breeding bird within the study area, although some nesting may have occurred. Most observations of this species were of adults foraging in and adjacent to crop fields.
Fairly common nesting species observed in all wooded habitats investigated. The study area breeding population was estimated at 1,025 females. Largest breeding densities were recorded in the willow shrub community and in serviceberry thickets where the densities were identical (77 pairs/km²).
Common nesting species in mesic upland forest habitats. Largest breeding densities were in mixed bur oak-green ash (23.5 pairs/km²) . Anderson and Shugart (1974) characterized scarlet tanager habitat in Tennessee as deciduous forest with dense canopy cover. Beals (1960) found them in dense deciduous forests in northern Wisconsin.
Fairly common nesting species of late seral stage deciduous habitats. Largest breeding densities in lowland forest (67 pairs/km²) were over 3 times greater than densities in bur oak forest (19 pairs/km²). Stewart (1975) described the breeding habitat of this species as semi-open mesophytic deciduous forest.
Fairly common nesting species associated primarily with the edge of second-growth bur oak forest. Mean breeding density in that habitat was 28 pairs/km². Bond (1957) reported that highest breeding densities in southern Wisconsin were in open xeric forest, and in forest edge.
Several singing males were observed in willow shrub along the Pembina River on 22 April. One male was still found there on 17 May. There were no summer observations.
Flocks of 6-20 pine siskins were encountered throughout the study area 22 April and 15-17 May. One male was recorded on a lowland forest census plot on 7 June. We found no evidence of nesting in the study area although pine siskins occurred throughout the summer in coniferous trees in the village of Walhalla, about 4 km east of the study area.
Common nesting species occupying all forested habitats investigated. Largest breeding densities were recorded in early seral stage deciduous habitats including serviceberry thickets (115 pairs/km²) and willow shrub community (69 pairs/km²). Stewart (1975) described the breeding habitat of this species in North Dakota as marginal zones of woodlands and brushland. Faanes (1981) classified this species as typical of edge habitats in the St.Croix River Valley of Minnesota and Wisconsin.
A flock of six red crossbills was observed in mixed bur oak-green ash forest on 22 July. No evidence of nesting was obtained.
Common nesting species of mesic and xeric upland habitats. The largest breeding density was recorded in mixed bur oak-green ash forest (38 pairs/km²). Stewart (1975) described the breeding habitat of the rufous-sided towhee in North Dakota as semi-open upland deciduous forest with a fairly dense understory of small trees and tall shrubs.
The savannah sparrow was occasionally observed foraging in scattered prairie remnants on the edge of bluffs, primarily downstream from Vang Bridge. We obtained no evidence of nesting in the study area, although the species was fairly common in seeded grasslands adjacent to the study area.
Uncommon and local nesting species usually associated with the brushy ecotone between young bur oak forest and cropland. The study area population was estimated at 246 breeding pairs. Bent (1968) reported that roadsides, open grassy and weedy areas, and hayfields or stubble were commonly used habitats in much of its range.
Probably a common spring and fall migrant. Most field work did not coincide with the normal peak periods of migration for this species. During late April, individual flocks of four to eight dark-eyed juncos were regularly encountered in early seral stage forests.
Probably a common to abundant migrant during normal migrant periods. Groups of 8-20 tree sparrows were regularly observed in willow shrub and bur oak forest during late April, and some stragglers were still present on 15 May.
Two singing males were observed throughout June in mixed bur oak and quaking aspen forest near the proposed dam site. It was unknown if these birds represented breeding pairs, primarily because of the lack of suitable coniferous trees.
Common nesting species throughout the study area occurring in all forested habitats investigated. This was the third most abundant breeding species in the study area. Largest breeding densities were recorded in serviceberry thickets (115 pairs/km²). Fox (1961) described this species as characteristic of wolfberry thickets on prairie grasslands. Faanes (1981) described breeding habitat in the eastern part of their range as edge situations including brushy fields, retired agricultural fields, and old field communities that were invaded with coarse perennial weeds, and brushy open areas in oak forest.
Groups of three to five migrants were frequently encountered in various edge habitats during late April.
Fairly common migrant during late April to mid-May when solitary birds and groups of two to four were found in various early seral stage forests. Stewart (1975) considered this a rare nesting species in the Pembina Hills, and showed a breeding season record for T. 164 N., R. 58 W. obtained 30 June 1962. Although apparently suitable breeding habitat existed in the study area, we found no evidence of nesting.
Solitary migrants were observed in the study area during 15-17 May, and on 8 September.
Fairly common nesting species occurring in all forested habitats investigated. Largest breeding densities were recorded in the willow shrub community (269 pairs/km²) . Beals (1960) reported highest nesting densities in northern Wisconsin from pioneer stage aspen forest. Roberts (1932) considered the song sparrow a characteristic species of brushy meadows, the banks of lakes and streams, prairie groves, upland fields, and clearings in Minnesota.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/pemhill/species.htm
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Menlo Park, CA [caww54]
