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The Cranes

Status Survey and Conservation Action Plan

Sandhill Crane

(Grus canadensis)


JPG-Sandhill Crane

Subjects:
Summary
Subspecies/populations
Population Numbers and Trends
Conservation Status
Historic and Present Distribution
Distribution by Country
Habitat and Ecology
Principal Threats
Current Conservation Measures
Priority Conservation Measures

Summary

With a total estimated population of more than 500,000, the Sandhill Crane is the most abundant of the world’s cranes. It is widely (though intermittently) distributed throughout North America, extending into Cuba and far northeastern Siberia. Six subspecies have been described. The three migratory subspecies—the Lesser, Greater, and Canadian Sandhill Cranes—are relatively abundant. They are distributed across a broad breeding range in northern North America and eastern Siberia, with wintering grounds in the southern United States and northern Mexico. The other three subspecies—the Mississippi, Florida, and Cuban Sandhill Cranes—exist as small, non-migratory populations with restricted ranges in the southern United States (Mississippi, Florida, and southern Georgia) and Cuba. The total population is increasing in numbers, although some local populations may be declining. The species is classified as Lower Risk under the revised IUCN Red List Categories. The Mississippi and Cuban subspecies are classified as Critically Endangered, and also listed on CITES Appendix I.

At the time of European settlement the species was probably more widely distributed than at present. The remote arctic and subarctic breeding grounds of the Lesser and Canadian Sandhill Cranes have been relatively free of human impact. However, the wintering grounds of these subspecies have been extensively altered. Hunting, agricultural expansion, drainage of wetlands, and other habitat changes in the 18th and 19th centuries led to the extirpation of the Greater Sandhill Crane from many parts of its breeding range in the United States and Canada. The population and range of the non-migratory Sandhill Cranes in the southern United States have also diminished due to hunting, loss of wetlands, and other changes in its habitat. The Cuban Sandhill Crane was probably more widely distributed in the Cuban archipelago than at present.

Sandhill Cranes are primarily birds of open freshwater wetlands and shallow marshes, but the different subspecies utilize a broad range of habitat types, from bogs, sedge meadows, and fens to open grasslands, pine savannahs, and cultivated lands. During the breeding season, the three migratory subspecies may be found in a wide variety of northern wetland communities. Habitats along migration routes tend to be large, open palustrine and riparian wetlands near agricultural areas, while wintering habitats include riparian wetlands, wet meadows, seasonal playa lakes, and pastures. The non-migratory subspecies use seasonally variable wetlands, grasslands, and palm and pine savannahs. Sandhill Cranes are omnivorous, feeding on a wide variety of plant materials (including waste grains) and small vertebrates and invertebrates, both on land and in shallow wetlands.

The leading threat to the species is the loss and degradation of wetland habitats, especially ecological and hydrological changes in important staging areas. Of special concern are the spring staging areas along the central Platte River, which have diminished due to changes in the river’s flow, and which are further threatened by excessive water withdrawals and potential dam construction projects. Loss of suitable roosting habitat has increasingly concentrated the migrating cranes, increasing the risks associated with disease, disturbance, and other threats. Habitat loss continues to have a major impact on breeding grounds of the Greater Sandhill Crane and on the year-round habitats of the non-migratory subspecies. Overhunting poses a potential threat to certain segments of the mid-continental Sandhill Crane populations. Lead and mycotoxin poisoning, abnormal predation pressures, and collisions with fences, vehicles, and utility lines are of local concern for various populations.

JPG - Sandhill Crane feeding newly fledged chick

Since the decline of the Sandhill Crane in the first half of the 1900s, extensive conservation measures have been undertaken on its behalf. These include: protection under the Migratory Bird Treaty of 1916; establishment of protected areas in key breeding, migration, and wintering habitats; stronger national wetland protection policies and programs; annual surveys and counts of many populations; wide-ranging research on many aspects of the species’ biology and ecology; management guidelines and plans for mid-continental and Rocky Mountain populations; development of a recovery plan, PHVA, and captive propagation and release program for the Mississippi Sandhill Crane; initiation of a research and management program for the Cuban Sandhill Crane; and a wide variety of public education programs.

Priority conservation measures for the species include: protection, restoration, and management of critical breeding, migration, and wintering habitat for the migratory subspecies (especially along the Platte River) and of the permanent habitats of the non-migratory subspecies; implementation of conservation programs and incentives that involve private landowners; research to improve understanding of the size, status, dynamics, distribution, and movements of populations; continued implementation and updating of the recovery plan for the Mississippi Sandhill Crane; development of a comprehensive Cuban Sandhill Crane conservation program; greater attention to problems associated with crop depredation; greater attention to the long-term effects of hunting on hunted populations; and clarification of intraspecific genetic structure and phylogenetic relationships.

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Subspecies/populations

Six subspecies are currently recognized:

Lesser Sandhill Crane G. c. canadensis
Canadian Sandhill Crane G. c. rowani
Greater Sandhill Crane G. c. tabida
Florida Sandhill Crane G. c. pratensis
Mississippi Sandhill Crane     G. c. pulla
Cuban Sandhill Crane G. c. nesiotes

The taxonomic status of, and relationships among, the Sandhill Crane subspecies have been discussed frequently in the literature (e.g., Walkinshaw 1973, Lewis 1977, Tacha et al. 1985). The G. c. canadensis-rowani-tabida group is probably clinal, with gradual changes in morphological characters and no positive means of distinguishing among them (except between G. c. canadensis and G. c. tabida at the extremes of their ranges). Random pairing among the three subspecies has been demonstrated, and intergrading occurs along the limits of their ranges (Tacha et al. 1985). G. c. pulla was described as a subspecies in 1972, based mainly on color differences between it and G. c. pratensis (Aldrich 1972). The existing population of G. c. pulla in Mississippi was probably more widespread in the past, and may have intergraded with G. c. pratensis and G. c. nesiotes to the east.

G. c. tabida is subdivided into five populations in this action plan. There are morphological differences among the populations, but they have not yet been analyzed in terms of their taxonomic significance. In many portions of the winter range, two or more subspecies occur together. Tacha et al. (1992) differentiate a total of nine geographic populations.

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Population Numbers and Trends

Subspecies Number Trend Source
G. c. canadensis     approx. 450,0001     Probably stable. Walter 1994,
R. Drewien pers. comm.
and
G. c. rowani Unknown due to
difficulty in
distinguishing from
Lesser Sandhills;
probably stable.
G. c. tabida 65-75,000 Increasing rapidly in
the eastern portion
of its range. Generally
stable elsewhere.
Some western
populations may be
declining.
Pogson and Lindstedt 1991,
Urbanek 1994,
Drewien et al. 1995
G. c. pratensis 4,000-6,000     Generally stable, with
local increases and
declines. Includes the
Okefenokee portion
of the population
(about 400 individuals).    
Tacha et al. 1994
G. c. pulla 120 Numbers in wild
increasing through
augmentation.
Reproduction in the
wild is below
replacement level.
S. Hereford pers. comm.
G. c. nesiotes 300 Generally stable.
New populations
recently discovered
X. Galvez and A. Perera,
pers. comm.
Total 520,000 Stable to increasing

This should be considered a conservative estimate. Tacha et al. (1992, 1994), using a geographic breakdown of populations and subpopulations, arrive at a total estimate of at least 652,500. Especially for the migratory subspecies, it has been difficult to confirm population numbers and establish trends. Improved aerial census techniques have begun to provide more reliable survey data, but these techniques have not been in use long enough to allow meaningful analysis of trends.

1Population estimates of the mid-continental populations of Sandhill Cranes are also included in the total). Estimates are based on 3-year running averages of spring counts conducted on the Platte River during migration. The figure given here represents the 1995 survey results for the midcontinental populations (420,866) pous about 25,000 Lesser Sandhill Cranes from California.

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Conservation Status

Species
IUCN category Lower Risk (Least Concern)
CITES Appendix II
    
Subspecies IUCN Category
Lesser (G. c. canadensis)     Lower Risk (Least Concern)
Canadian (G. c. rowani) Lower Risk (Least Concern)
Greater (G. c. tabida) Lower Risk (Least Concern)
Florida (G. c. pratensis) Lower Risk (Least Concern)
Mississippi (G. c. pulla) Critically Endangered, under criterion C2b
(also on CITES Appendix I)
Cuban (G. c. nesiotes) Critically Endangered, under criterion C2a
(also on CITES Appendix I)

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Historic and Present Distribution

GIF-Distribution Map

The Sandhill Crane breeds primarily in northern North America and extreme northeastern Siberia, and winters in northern Mexico and the southern United States. Non-migratory populations are found in Mississippi, Florida, and Georgia in the southern U.S., and in Cuba. There are few reliable records regarding the distribution of the Sandhill Crane at the time of European settlement. The species was probably more widely distributed, especially in its southern breeding range (Tacha et al. 1992). At the species level, the Sandhill Crane reached its low point in terms of conservation status in the mid- to late-1930s, after hunting had extirpated or depleted many populations and European settlement (mainly through agricultural expansion and the conversion of wetlands) had deprived it of much of its original habitat in the southern portions of its range. The historic and present ranges of the subspecies and their constituent populations are as follows:

Lesser Sandhill Crane (G. c. canadensis)

The breeding grounds of the Lesser Sandhill Crane are scattered throughout the arctic and subarctic regions of northern Canada from Baffin Island to the Yukon Territory; in coastal and interior areas of Alaska; and in northeastern Siberia (including the lower Anadyr River watershed, coastal areas west to the Indigirka River, and the Kamchatka Peninsula) (Walkinshaw 1973, Krechmer et al. 1978, Kishchinski et al. 1982, Labutin and Degtyaryev 1988). The population inhabiting Banks Island and other arctic islands may be distinct (Reed 1988). The Lesser Sandhill Crane intergrades on the southern edge of its mid-continental summer range with the Canadian Sandhill Crane (Walkinshaw 1973, Johnsgard 1983, Tacha et al. 1985).

The large migratory flocks of Sandhill Cranes that congregate on the Platte River in the spring consist primarily of this subspecies, along with most of the Canadian Sandhill Crane population and smaller numbers of Greater Sandhill Cranes (see below). Stopover points for the mid-continental populations of these subspecies are scattered throughout the plains, but some 80-90% of them (between 350,000 and 450,000) stay for up to six weeks on the river flats of the Platte and North Platte Rivers (Walkinshaw 1949, 1973; Johnson and Stewart 1973; Lewis 1977; Tacha et al. 1992). Along the Platte, Greater Sandhill Cranes are generally found disproportionately around Grand Island, Nebraska (at the eastern edge of the staging area), Canadian Sandhill Cranes in the middle stretches of the staging area, and Lesser Sandhill Cranes in the western end around North Platte, Nebraska (Tacha et al. 1984.; J. Lewis pers. comm.).

The main part of the population (about 80%) winters in the seasonal playa lakes and riparian wetlands of eastern New Mexico, northwestern Texas, and northern Mexico (Iverson et al. 1985, Drewien et al. 1996). A smaller portion of the flock, mainly from southeastern Alaska, migrates through Washington and Oregon and winters in California’s Central Valley and Carissa Plains (Littlefield and Thompson 1979, 1982; Mickelson 1987).

The breeding grounds of the Lesser and Canadian Sandhill Cranes have been relatively free of direct human impact. However, portions of the wintering grounds of these subspecies in the southwestern United States and northern Mexico have been extensively altered by agricultural development.

Canadian Sandhill Crane (G. c. rowani)

The Canadian Sandhill Crane is probably a transitional race between the arctic-dwelling Lesser Sandhill Crane and the more temperate Greater Sandhill Crane (Tacha et al. 1985). Thus it is difficult to define with any certainty its range limits. In general, its breeding grounds are scattered across subarctic Canada between 500 and 600 N, from northern Ontario through northern Alberta, Saskatchewan, and Manitoba to west-central British Columbia. Birds from the eastern portion of this range winter mainly in coastal Texas with Greater Sandhill Cranes. The wintering grounds of the western populations of the Canadian Sandhill Crane are not well established. They likely share areas in California, New Mexico, Mexico, and Texas with the western populations of Lesser and Greater Sandhill Cranes.

Greater Sandhill Crane (G. c. tabida)

The breeding range of the Greater Sandhill Crane spans mid-continental North America from the Great Lakes to the Pacific Ocean. Scientists generally divide the Greater Sandhill Crane into four distinct regional populations. A fifth population, the Prairie population, is added here based on new information about migration routes and wintering grounds.

  1. Eastern population

    The breeding grounds of the Eastern (or Great Lakes) population are in southcentral Canada, the western Great Lakes, and the Upper Midwest (southern Ontario, Michigan, Wisconsin, northern Illinois and Iowa, and southeastern Minnesota). During the 1994 fall census (Urbanek 1994), 26,187 birds were tallied. The population likely exceeds 30,000. The main portion of the population migrates through the east-central United States (Illinois, Indiana, Ohio, Tennessee, Kentucky) to wintering grounds in southern Georgia and central Florida (Walkinshaw 1973, Lewis 1977). The Jasper-Pulaski Fish and Wildlife Area in northwest Indiana is a critical migration stopover point. Birds from the western parts of the breeding range may migrate down the Mississippi Valley to wintering areas on the Texas Gulf Coast.

    The James Bay lowland and Great Lakes populations are distinct. Distributions of the James Bay lowland cranes (which are likely G. c. rowanii) and the Great Lakes cranes have probably only become contiguous (and then to only a minor degree) in the last few decades, as both populations have increased and populated small isolated pockets of suitable habitat in the otherwise unsuitable Canadian Shield. The James Bay lowland cranes do not join with the Great Lakes sandhills during migration. Rather, they migrate southwestward to the Central Flyway and then south to wintering grounds in Texas (R. urbanek, pers. comm. 1996). Further study of the taxonomy and migration of the James Bay lowland cranes is needed to clarify their relationship to the Great Lakes birds.

    This population has recovered dramatically in recent decades, and continues to expand back into areas of its historic range. Hunting, agricultural expansion, drainage of wetlands, and other habitat changes in the 18th and 19th centuries led to its extirpation from both breeding and wintering grounds in the United States (Walkinshaw 1949, 1973; Leopold 1949). As the wetlands, prairies, and plains of the midwestern and western U.S. were transformed in the second half of the 19th century, breeding populations dwindled. Declines were most dramatic from about 1890 to the early 1930s. The Sandhill Crane disappeared as a breeding bird from Illinois (1890), Iowa (1905), South Dakota (1910), Ohio (1926), and Indiana (1929), and was almost extirpated from several others (Johnsgard 1983). In Wisconsin, the Sandhill Crane was reduced to about twenty-five breeding pairs in the 1930s (Henika 1936).

    Since then, hunting prohibitions and the protection, restoration, and management of wetlands have allowed the population to increase significantly, especially in Wisconsin, Michigan, and other portions of the western Great Lakes (Walkinshaw 1973, Dietzman and Swengel 1994). From these core areas, breeding populations have returned to other portions of the historic range. In recent years, Sandhill Cranes have returned as breeding birds in Illinois (in 1979), southeastern Minnesota (in the mid-1980s), Ohio (in 1988), Iowa (in 1992), and Pennsylvania (in 1994). Vagrants are occasionally reported from further east. The subspecies remains extirpated from large portions of the historic former range, but the continuing recovery and dispersal of the breeding populations may allow it to continue reclaiming these areas.

  2. Prairie population

    The prairie population, which includes perhaps 10,000-15,000 birds, breeds in the marshes and wet prairies of northwestern Minnesota, southwestern Ontario, and southern Manitoba. The population formerly extended into North and South Dakota, but last bred in these states in the late 1800s. In the last twenty years, occasional nesting has been reported in North Dakota, most recently at J. Clark Salyer National Wildlife Refuge (G. Krapu pers. comm.). It is unclear whether the Sandhill Cranes in the greater region represent a recovering remnant or reoccupying population. There are regular historic records of Sandhill Cranes in the region, suggesting that the species was able to persist through the main period of European settlement and has recently begun to expand (D. Hjertaas pers. comm.). These birds migrate through the Dakotas, Nebraska, Kansas, and Oklahoma to wintering grounds along the eastern Texas coast of the Gulf of Mexico west of Houston, which they share with wintering Canadian Sandhill Cranes (Guthery et al. 1979, Melvin 1982, Melvin and Temple 1982, Tacha et al. 1984).

  3. Rocky Mountain population

    In recent years, the Rocky Mountain population has been estimated at 18,000-21,500 (Benning 1991, Tacha et al. 1992, Drewien 1995, Drewien et al. 1995b). The breeding grounds of the population are in west-central and southwestern Montana, central and eastern Idaho, northeastern Utah, western Wyoming, and northwestern Colorado. The migration route crosses Utah, Colorado, and New Mexico, with a major spring and fall staging area in Colorado’s San Luis Valley. The main wintering grounds are in the middle Rio Grande valley in New Mexico, with other scattered locations in southwestern New Mexico, southeastern Arizona, and north-central Mexico (Drewien and Bizeau 1974, Lewis 1977, Drewien et al. 1996).

    All the western populations of Greater Sandhill Cranes are believed to have been more abundant prior to European settlement. The breeding range formerly extended south into Arizona and northern Mexico (Tacha et al. 1992). The more southern of these populations were likely non-migratory, or migrated only short distances on a seasonal basis. The Rocky Mountain population reached an historic low of 150-200 breeding pairs in the 1940s. Since then it has recovered dramatically, but may now be declining due to the effects of regional drought, poor survival of chicks, and increased hunting pressure. Drewien et al. (1995b) regard the population as stable to slightly declining.

  4. Colorado River Valley population

    The population is estimated at 1400-2100 and is considered stable (Rawlings 1992, Tacha et al. 1992). However, no surveys have been undertaken recently (Tacha et al. 1992). The population breeds in northeastern Nevada and southwestern Idaho, migrates through Nevada (with a spring stopover near Lund), and winters along the lower Colorado River in Arizona, in California’s Imperial Valley, and along the Gila River in southwestern Arizona (Lewis 1977, Drewien et al. 1987).

  5. Central Valley population

    The 6000-6800 cranes in the Central Valley population breed mainly in south-central and southeastern Oregon and northeastern California, with additional breeding areas up to southern British Columbia and Vancouver Island (Pogson 1990, Pogson and Lindstedt 1991). In the winter, these cranes migrate to the Central and Imperial Valleys of California (Lewis 1977, Littlefield and Thompson 1979). This population is believed to be increasing.

GIF-Distribution Map: Florida and Mississippi Subspecies

Florida Sandhill Crane (G. c. pratensis)

The non-migratory Florida Sandhill Crane occurs in peninsular Florida from the Everglades (where they have probably always been present, but never abundant) north to southern Georgia (Charlton and Ware counties) in and around the Okefenokee Swamp (Bennett 1989, Nesbitt and Williams 1990). The subspecies is most abundant in the region of Florida’s Kissimmee and Desoto Prairies.

The range of Sandhill Cranes in the southeastern United States diminished steadily following European settlement (Walkinshaw 1949, 1973). Non-migratory Sandhill Cranes may have once formed a single extended population in the southeastern U.S. and Cuba. Over time, overhunting, loss of wetlands, conversion of habitat to agriculture, land development, deforestation, and afforestation are thought to have reduced and fragmented the population of resident Sandhill Cranes in the region. Sandhill Cranes are known to have nested in coastal Texas until 1900, in Alabama until 1911, and in southern Louisiana as late as 1919 (Walkinshaw 1949, 1973; Johnsgard 1983). Over the decades, nesting cranes have been reported intermittently in southwestern Alabama. The Mississippi Sandhill Crane (see below) may represent the western remnant of this formerly more extensive population.

Despite these historic losses, the Florida Sandhill Crane has proven to be adaptable. It has benefitted from the establishment of protected areas in key portions of its remaining range. As a result, its population and distribution have stabilized in recent decades.

Mississippi Sandhill Crane (G. c. pulla)

The original distribution and abundance of the subspecies is unknown, but may have been part of a more extensive resident population in the southeastern U. S. (see above). Its habitat had already been extensively altered and its numbers reduced by the time the cranes were first surveyed (Leopold 1929). The subspecies now occurs only in Jackson County, Mississippi in the United States, between the Pascagoula River and the Harrison-Jackson County line (Valentine and Noble 1970, USFWS 1991). Only since the late 1980s has the total number of birds in the wild risen above 100. The resident population is supplemented by annual releases of captive-bred birds, but reproduction in the wild has consistently fallen below replacement levels (Valentine and Logan 1991, Ellis et al. 1992). The entire wild and reintroduced population of approximately 120 birds (as of September 1994) occurs on and near the Mississippi Sandhill Crane National Wildlife Refuge. Of the refuge’s 19,300 acres, about 12,500 can be used by cranes (S. Hereford pers. comm.). The subspecies is reproductively isolated from other populations of Sandhill Cranes. Over the past several decades, breeding cranes—most likely from this subspecies—have occasionally been reported in southern Louisiana and Alabama (USFWS 1991).

GIF-Distribution Map: Cuban Subspecies

Cuban Sandhill Crane (G. c. nesiotes)

The Cuban Sandhill Crane is endemic to the island of Cuba and nearby islands and keys of the Cuban archipelago. It is the largest bird in Cuba and the West Indies, and the only crane that occurs in the Caribbean or Central and South America (Galvez and Perera 1995). Little is known about its historic distribution. It was likely distributed widely throughout Cuba. There are historic records of its occurrence at Pinar del Rio, Havana Province, Matanzas Province, and Santa Clara (in addition to areas in which it survives) (Johnsgard 1983). Since the early 1960s, however, its range and numbers have diminished (Galvez and Perera 1995).

The remnant population now occurs at ten known disjunct locations in Cuba: (1) savannas near the Pinar Del Rio near Guanes, at the western end of the Cuban mainland; (2) savannas and wetlands of the central and northern Pinar del Rio; (3) the Isle of Youth (also known as the Isle of Pines) near Los Indios; (4) Zapata Swamp, Mantanzas Province; (5) Las Guaya Beras Swamp north of Sancti Spiritus Province; (6) savannas and wetlands at Moron, north of Cielo de Avila Province; (7) Jucaro, south of Cielo de Avila Province; (8) Cayo Romano, north of Camaguey Province; (9) savannas of San Felipe and Lesca in Camaguey Province; and (10) the Cauto River Delta in Granma Province (A. Perera pers. comm.). Their status in these areas is poorly understood. The first comprehensive survey of their known and possible habitats was carried out in October 1994 (Galvez and Perera 1995).

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Distribution by Country

Canada B, M
Cuba R
Japan V
Mexico W
Russia B
United States     B, M, R, W
    
B = Present during breeding season
M = Present during migration
R = Permanent resident
W = Present during winter
V = Vagrant

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Habitat and Ecology

JPG-Savannah habitat of Cuban Sandhill Crane

Sandhill Cranes are primarily birds of open freshwater wetlands, shallow marshes, wet meadows, and adjacent uplands. They utilize a broad range of habitat types, from bogs, sedge meadows, and fens to open grasslands, stubble fields, and savannahs. They are omnivorous, feeding on a wide variety of plant materials (including waste grains), invertebrates, and small vertebrates, both on land and in shallow wetlands. For reviews of the species’ breeding, migration, and winter habitats, food habits, behavior, breeding biology, and demographics, see Walkinshaw (1949, 1973), Johnsgard (1983), and Tacha et al. (1992, 1994). During the breeding season, the three migratory subspecies utilize a wide variety of northern wetland types. Lesser Sandhill Cranes occur mostly in wetlands of the arctic lowland coasts, river deltas, and tundra, including bogs, shallow lakes, seasonal ponds, and riparian marshes. In some areas it nests on grassy hillsides and dunes and in shrubby wet meadows. The subarctic habitats of the Canadian Sandhill Crane consist of muskeg and other shallow wetland communities, open and forested bogs, and other boreal forest wetland types. Greater Sandhill Cranes are typically found in bogs, fens, cattail marshes, sedge meadows, shrub carrs, and other wetland types, as well as wetter open parklands, riparian areas, flooded meadows, and beaver ponds (Walkinshaw 1973, Drewien and Bizeau 1974, Johnsgard 1983). In the more arid parts of its western breeding range, it is found in shallow wetlands and along rivers. In agricultural areas, it prefers nesting sites close to cultivated fields. The size of nesting territories varies widely within the breeding range. Drewien (1973) found territories averaging 17 ha in Idaho; Walkinshaw (1973) reported an average of 85 ha in Michigan’s Upper Peninsula.

Nests in wetland sites are built of the dominant vegetation in the nesting area; dry site nests are minimally prepared. The incubation period is 29-32 days, and chicks fledge at 67-75 days (Drewien 1973). Average fledging periods tend to be longer for southern populations.

Habitats along migration routes tend to be large, open marshes and riparian wetlands near agricultural areas, especially harvested grain fields, hay fields, and pastures (Soine 1982, Melvin and Temple 1982). Krapu et al. (1984), Currier et al. (1985), Iverson et al. (1987), and Folk and Tacha (1990) describe habitats of the mid-continental populations on the Platte River and at other points along its spring migration route. The migratory subspecies are found in widely varying winter habitats, including pastures and wet meadows in Florida (often shared with resident Florida Sandhill Cranes); coastal and freshwater marshes, coastal prairies, and stubble fields along the Texas Gulf Coast; seasonal playa lakes and other shallow lakes and riparian wetlands in west Texas, New Mexico, and Arizona; and large marshes, irrigated pastures and croplands, grain fields, and dairy farms in southern California and other parts of the American Southwest and adjacent Mexico (Tacha et al. 1992, Drewein et al, 1996).

The non-migratory subspecies favor seasonally variable wetlands, grasslands, and pine and palm savannahs. Florida Sandhill Cranes use shallow freshwater wetlands, wet prairies, and savannahs. The birds at Okefenokee Swamp tend to prefer more open marshes, and make little use of drier upland habitats (Bennett 1989). Although this subspecies has lost much habitat to agricultural expansion and development, it has adapted to the pastures that now occupy large portions of its historic range. Preferred habitats include wetland/grassland and grassland/forest transitional zones and upland areas near water (such as hammocks and sloughs) (Nesbitt and Williams 1990). In recent years, however, increasing human population and development pressures have caused it to nest in ditches, near artificial pools, and in other improbable sites. Common food items include tubers, seeds, acorns, and berries, as well as crops (especially corn and peanuts) and invertebrate animals (Nesbitt in press).

The endangered Mississippi and Cuban Sandhill Cranes are now confined to drier or seasonally flooded habitats. The limited territory of the Mississippi Sandhill Crane consists of pine savannahs dominated by wiregrass and a rich herbaceaous community, with scattered longleaf pine, slash pine, and pond cypress. Marshes and pine plantations also are found within the area. The cranes nest in mesic to wet savanna as well as wetland edges, and roost in freshwater and slightly brackish marshes, artificial ponds, and savannahs (Valentine and Noble 1970, USFWS 1991). Much of this habitat has been altered since the 1940s by afforestation and urban and agricultural development (Smith and Valentine 1987). The Cuban Sandhill Crane occupies relatively dry upland grasslands, hammocks, and pine and palmetto savannahs, often associated with wetlands (Walkinshaw 1949, Faanes 1990, X. Galvez pers. comm.). Some pairs of the non-migratory cranes remain on their breeding territories throughout the year (this is particularly true of the Okefenokee population of Florida Sandhill Cranes). Others gather in flocks and forage on agricultural gleanings, in pastures, and (in the case of the Mississippi Sandhill Crane) food plots within refuges.

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Principal Threats

JPG-Sandhill Cranes at spring staging area on the Platte River, Nebraska, USA

Loss and degradation of wetlands and other habitats are the most important threats to Sandhill Crane populations. For the migratory subspecies, this is of greatest concern in staging and wintering areas, where changes in land use, hydrology, and vegetation have reduced available habitat and concentrated the flocks during the non-breeding season. The drier meadow, savannah, and other upland habitats to which the non-migratory subspecies are partially adapted have also been widely altered by agricultural conversion and development.

The spring staging areas along the Platte River are of special concern because of their importance to the mid-continental crane populations and other migratory birds (see Johnsgard 1984, Currier et al. 1985, VanDerwalker 1987, Faanes 1988). With about 80% of the total Sandhill Crane population using the Platte River during the spring, the long-term loss of habitat quality at this site constitutes the most critical threat to the species. Over the last century, construction of upstream dams and water withdrawals have reduced the flow of the Platte by some 70% and have altered the river’s historic hydrologic regime (Currier et al. 1985). This in turn has allowed riparian vegetation to encroach upon the riverbanks, and altered the process of sand bar formation within the channel (Faanes 1988, Faanes and Bowman 1992, Farrar 1992). Flood control structures, agricultural conversion, and gravel mining have reduced by some 75% the total area of native grassland and wet meadow adjacent to the river (Currier et al. 1985). These meadows are critical habitat for pair formation activity and for foraging, providing food items high in nutrients (Frith 1974, Krapu 1981). As a result, the stretch of river providing the necessary mixture of feeding and roosting habitats has shrunk from about 200 miles to about 80 miles, with consequent increases in flock concentration in the remaining suitable roosting areas (P. Johnsgard pers. comm.). Fundamentally, the quality of habitat along the Platte River will depend on the maintenance of minimum flows rates from upstream dams (in particular the Kingsley Dam on the North Platte River north of Ogallala) and control of maximum usage rates downstream (Faanes 1988, Faanes and Bowman 1992).

Overhunting poses a potential risk to migratory populations in western and central North America. The three migratory subspecies are hunted in portions of their ranges in Russia, Canada, the United States, and Mexico (the Mississippi, Cuban, Florida, and Eastern and Central Valley populations of Greater Sandhill Cranes are not hunted). Canadian Sandhill Cranes and the Prairie population of Greater Sandhills, because of their more southern distribution, are exposed to disproportionately heavy hunting pressure. Since the mid-1980s the total estimated annual kill (including crippling losses) in the mid-continental populations has ranged between 25,000 and 31,700, or about 4-5.4% of the fall population (Sharp and Vogel 1992, Central Migratory Shore and Upland Game Bird Technical Committee 1993, Tacha et al. 1994).

The hunted populations are managed according to management plans (summarized under “Management and Recovery Plans” below). However, Tacha et al. (1994) note that “funds for research to improve management have been limited,” even as “substantial additional information is required to facilitate population, harvest, and/or habitat management.” Drewien et al. (1995) note that the Sandhill Crane has the lowest recruitment rate of any bird now hunted in North America, and caution that “no long-term data on recruitment or survival have been collected” for the mid-continental populations. At present, few long-term studies of the effects of hunting on the different subspecies and populations are underway. Research on the racial composition of the mid-continental populations does provide important foundations for such studies (see Johnson and Stewart 1973, Johnson 1979). For the Lesser and Canadian Sandhill Cranes in particular, clear management objectives, reliable data on population sizes, disturbance, and recruitment rates, and a definitive understanding of intraspecific genetic relationships are lacking. Although these gaps in knowledge do not threaten the species as a whole in the short term, the effects on specific breeding populations are unknown.

Other threats to the species are more localized. Mycotoxins ingested through the consumption of waste peanuts have caused large-scale mortality (up to 5,000 individuals), while lead poisoning and collisions with fences and utility lines also cause injury and death (Brown et al. 1987, Windingstad 1988, Allen and Ramirez 1990, Ward and Anderson 1992). The concentrated migratory flocks along the Platte River are susceptible to outbreaks of avian cholera and other diseases. Increasing public interest in the cranes along the Platte may also result in increased disturbance of the birds at these sites. Although pesticide residues have sometimes been found in relatively high levels in Sandhill Cranes, this has not been shown to have detectable impacts, and pesticides are not considered a major threat.

The principal threats at the subspecific level are as follows:

Lesser and Canadian Sandhill Crane

The loss and alteration of riparian habitat at the migration stopover points along the Platte River constitute the most important threat to the Lesser and Canadian Sandhill Cranes. Other important threats include degradation of wintering grounds in Texas, New Mexico, and Mexico, and the susceptibility of the population to drought and resultant loss of roosting sites in these areas. About 80% of the mid-continental populations of these subspecies winter on fewer than 20 lakes in western Texas (Iverson et al. 1985). On one of these lakes, concentrations of as many as 300,000 cranes have been recorded; more than 100,000 commonly roost on several others (Tacha et al. 1994). The most important wintering area in Mexico, Laguna de Babicora in Chihuahua, is also threatened by proposed habitat alterations (Drewien et al. 1996). Expanding the effort to protect these habitats is a high conservation priority.

Greater Sandhill Crane

The destruction and degradation of habitats—especially wintering grounds in California and Florida, breeding grounds in the American upper midwest, and migration stopovers on the Platte River and other portions of the plains states—comprise the most important current threat to the Greater Sandhill Crane. The habitats of the Rocky Mountain population are increasingly affected by residential and commercial development, changing agricultural practices, drainage of wetlands, water diversions, oil and gas exploration and development, and other land use changes. Increased concentration of populations in the Rocky Mountains and other areas have led to increased risk of disease and crop depredation (Smith 1991).

Florida Sandhill Crane

Agricultural, residential, and commercial development in Florida has reduced and fragmented the habitat of the Florida Sandhill Crane population. This has affected shallow wetlands, wet savannahs, upland savannahs, and open upland feeding areas. The preferred wetland community type—pickerel weed and maidencane—is also highly susceptible to vegetation change, shifting to cattail (Typha spp.) and willow (Salix spp.) and other woody species as a result of alterations in the quantity and quality of instream flow. The cranes in Florida are also prone to accidental collision with fences, automobile collisions, and disturbance from free-ranging domestic dogs and cats (Nesbitt in press).

Mississippi Sandhill Crane

The Mississippi Sandhill Crane has declined in large part due to long-term habitat loss and degradation. It is now subject to a broad range of interrelated threats, including: insufficient habitat (especially prime breeding grounds) as a result of the spread of pine plantations, fire suppression, road construction, and urban encroachment; high predation pressures (especially on nests, chicks, and recently released juveniles), primarily from coyotes; drier habitat conditions as a result of changes in the hydrologic regime of its remaining habitat; vulnerability to drought, hurricanes, and other catastrophic events; exposure to pesticides and toxic chemicals; loss of genetic diversity within the population; accidental shootings; collisions with vehicles and utility lines; and high rates of disease and tumor formation, possibly due to environmental toxins (USFWS 1991). These factors have contributed to low reproduction and survival rates, and a consequently low recruitment rate, within the population (S. Hereford pers. comm.).

Cuban Sandhill Crane

The Cuban Sandhill Crane is subject to many of the same threats facing the other non-migratory Sandhill Cranes: changes in the hydrology and fire regime of its savannah habitat; loss of habitat to deforestation, development, land reclamation, and agricultural expansion; vulnerability to catastrophic weather events; and genetic and demographic problems due to its small and fragmented population. Feral pigs and dogs may affect the breeding success of the cranes within the Las Salinas Wildlife Refuge in the Zapata Swamp. Habitat conversion (especially due to the development of citrus plantations) is the principal factor behind the significant decline of the cranes on the Isle of Youth (Galvez and Perera 1995). Hunting may also be a problem, especially given the economic pressures within Cuba. Cuba’s political isolation has also limited the availability of information, funding, equipment, and scientific and management expertise, and hindered cooperative conservation measures to address these threats.

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Current Conservation Measures

Since declining through the first half of the 1900s, the Sandhill Crane has benefitted from extensive conservation efforts. See Walkinshaw (1949, 1973), Johnsgard (1983, 1991), and Tacha et al. (1992, 1994) for overviews of these efforts.

Legal and Cultural Protection

In Canada and the United States, the hunting of Sandhill Cranes is regulated under the Migratory Bird Treaty of 1916. Hunting was prohibited until increased interest in Sandhill Cranes as game animals led to the opening of hunting seasons in Canada in 1959 and in the United States in 1961 (Central Migratory Shore and Upland Game Bird Technical Committee 1993). The species has been legally hunted in Mexico since at least 1940. In the U.S., Sandhill Cranes are now legally hunted in Alaska, Arizona, Colorado, Kansas, Montana, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming. In Canada, Sandhill Cranes are hunted in Saskatchewan and Manitoba. In Mexico, hunting is permitted in nine northern and central states (Tacha et al. 1994).

Both the Cuban and Mississippi Sandhill Crane are protected under the U.S. Endangered Species Act. The Florida Sandhill Crane is listed as a threatened species by the Florida Game and Freshwater Fish Commission. In Mississippi the Mississippi Sandhill Crane is listed as endangered and is protected under the state’s Nongame and Endangered Species Act of 1974 (USFWS 1991). The Cuban Sandhill Crane is listed as Endangered in Cuba.

International Cooperation and Agreements

All of the main range countries of the Sandhill Crane are parties to the Ramsar Convention. In Canada and the United States the species falls under the protection of the Migratory Bird Treaty. The treaty allows for the prohibition or regulation of hunting and other forms of direct exploitation. In 1936, the U.S. and Mexico signed a similar Treaty for the Protection of Migratory Birds and Game Mammals. While hunting has been legalized in certain portions of the species’ range, the provisions of these treaties remain in effect for the species as a whole.

Canadian and U.S. agencies collaborate in developing mid-continental Sandhill Crane management plans. Since 1994, crane conservationists in Cuba and the United States have worked more closely on Cuban Sandhill Crane conservation efforts (Galvez and Perera 1995).

Protected Areas

Sandhill Cranes use many national, provincial, and state protected areas as well as private conservation lands. A few areas, such as the Mississippi Sandhill Crane National Wildlife Refuge, are especially significant for cranes, and have been protected primarily for that reason. In most cases, however, cranes are only one of many species that benefit from the protected status of these areas. The breeding grounds of the mid-continental populations in Canada are found largely outside of protected areas. Nonetheless, many of Canada’s national and provincial parks and refuges do protect breeding cranes and their habitats.

Protected areas have played a key role in the protection and recovery of Greater Sandhill Crane populations in the United States, especially in the Great Lakes and Rocky Mountain states. Among the many important protected areas used by breeding Greater Sandhill Cranes are: Seney National Wildlife Refuge (NWR) in Michigan; Necedah and Horicon NWRs in Wisconsin; Sherburne and Crane Meadows NWRs in Minnesota; Seedskadee and Cokeville Meadows NWRs and Yellowstone and Grand Teton National Parks in Wyoming; Bear Lake, Camas, and Grays Lake NWRs in Idaho; and Malheur NWR in Oregon.

Among the refuges used by migrating cranes are: Jasper-Pulaski Fish and Wildlife Area in Indiana; Last Mountain Lake National Wildlife Area in Saskatchewan; Chase Lake and Long Lake NWRs and the Audubon Complex in North Dakota; Medicine Lake NWR in Montana; Bear Lake and Grays Lake NWRs in Idaho; Ouray, Bear River, and Fish Springs NWRs in Utah; Monte Vista/Alamosa NWR in Colorado; LaCreek NWR in South Dakota; North Platte NWR in Nebraska; Cheyenne Bottoms State Wildlife Area and Kirwin and Quivira NWRs in Kansas; and Salt Plains, Tishomingo, and Washita NWRs in Oklahoma.

Important wintering areas are protected in the Cibola NWR in Arizona; Bosque del Apache, Grulla, and Bitter Lake NWRs in New Mexico; and Muleshoe, Aransas, Brazoria, and Laguna Atascosa NWRs in Texas.

Protected areas have been especially important in efforts to protect the non-migratory subspecies. Large areas of Florida Sandhill Crane habitat are protected within a matrix of state parks, preserves, and wildlife management areas and private conservation lands (Nesbitt in press). These areas are also important for wintering Greater Sandhill Cranes from the Great Lakes population. In Georgia, the Okefenokee NWR protects critical Florida Sandhill Crane habitat. The Mississippi Sandhill Crane NWR was officially established in 1975 to protect the core habitat of the Mississippi Sandhill Crane. Four of the known sites where the Cuban Sandhill Crane occurs are within existing protected areas: Las Salinas Wildlife Refuge in Zapata Swamp; Los Indios Wildlife Refuge on the Isle of Youth; Romano Key Managed Resource Area in Camaguey Province; and Cauto River Delta Wildlife Refuge in Granma Province. Three other populations are adjacent or close to protected areas: the Guanes population in western Pinar del Rio is near the Peninsula de Guanahacabies Biosphere Reserve; the north Sancti Spiritus population is near the Caya Caguanes Nature Preserve and Jobo Rosado National Wildlife Refuge; and the north Cielo de Avila population is near the Cunagua Managed Resource Area (A. Perera pers. comm.).

Habitat Protection and Management

Sandhill Cranes have benefitted from many national, provincial, and state policies and programs to conserve wetlands, especially in parts of the United States where populations were depleted or extirpated. This pertains to habitat both within protected areas and on private lands. Restoration of hydrological regimes through reflooding and management of water levels has played a critical role in reestablishing the ecological functions and diversity of previously drained wetlands, especially in the upper midwestern United States. In some areas, habitat management programs have been undertaken specifically for cranes. The Platte River Whooping Crane Trust, which was established by a federal court ruling, is responsible for acquiring lands and restoring crane habitat (especially through the clearing of riparian vegetation) on the central Platte River (Strom 1987, Currier 1991). Prescribed burning has also been used to restore open meadows and savannahs in Mississippi, Texas, and other areas used by cranes (S. Hereford pers. comm.). In and near many of the important staging areas, food crops have been planted both to benefit cranes directly and to lure them away from commercial croplands (USFWS 1991). Behavioral studies have led to the development of new methods to reduce crane collisions with utility lines (Morkill and Anderson 1992, 1993).

Surveys/Censuses/Monitoring

The mid-continental populations of Sandhill Cranes are monitored through annual spring surveys. Annual aerial surveys along the Platte River in Nebraska date to 1957. Since 1974, annual surveys have been conducted in late March throughout the Central Flyway. The Rocky Mountain population of Greater Sandhill Cranes is monitored by the U.S. Fish and Wildlife Service in the San Luis Valley in Colorado during spring migration. Surveys are also conducted annually at Grays Lake NWR and at staging and wintering areas in Montana, New Mexico, and Utah (Smith 1991, Central Migratory Shore and Upland Game Bird Technical Committee 1993, Drewien et al. 1995). The wintering Colorado River Valley population has been counted on a semi-regular basis, most recently in November 1994 (Drewien 1995). Drewien et al. (1996) provide a summary of data on the distribution and abundance of wintering cranes in Mexico. Since 1974, an annual “crane count” has been held in Wisconsin and parts of adjacent Minnesota, Michigan, and Illinois, providing an index to the size the population of Greater Sandhill Cranes in the upper midwest (Dietzman and Swengel 1994). An annual fall census of the Eastern population is coordinated by the USFWS (Urbanek 1994). The Mississippi Sandhill Crane population is monitored year-round, and its size estimated semi-annually through censuses conducted in January and October (S. Hereford pers. comm.). The Cuban Sandhill Crane has been surveyed only intermittently since the mid-1940s. The first range-wide survey was undertaken in late 1994 and early 1995 (Walkinshaw 1973, Faanes 1990, Galvez and Perera 1995).

Research

The Sandhill Crane is among the most thoroughly studied crane species, and has long been among the most studied wildlife species in North America. Field research has been conducted in various parts of the species’ range, and has focused on a wide array of topics involving life history, breeding biology, ecology, ethology, migration, and demography. Carey Krajewski of Southern Illinois University is conducting continuing studies of mitochondrial DNA to define more precisely the phylogenetic relationships and degree of genetic variance within the species (Krajewski and Fetzner 1994, Krajewski and Archibald in prep.). Results from many of the studies of Sandhill Cranes have been reported within the proceedings of the North American and international crane workshops. The Unison Call, the biannual newsletter of the North American Crane Working Group, provides regular summaries of ongoing studies. Tacha et al. (1992, 1994) provide thorough syntheses of this information.

Much of the recent research on the species derives from its importance as a surrogate in efforts to reestablish Whooping Crane populations. The cross-fostering experiment at Grays Lake, Idaho, entailed extensive studies of the Rocky Mountain population of Greater Sandhill Cranes (e.g., Drewien and Bizeau 1974, Drewien et al. 1987). Since the mid-1980s, the Florida Sandhill Crane has been the subject of intensive monitoring, demographic studies, and ecological research related to efforts to establish a non-migratory flock of Whooping Cranes in Florida (e.g., Walkinshaw 1982, Bishop 1988, Nesbitt and Williams 1990). These ongoing studies have provided a strong basis as well for conservation of the Florida Sandhill Crane itself. The precarious state of the Mississippi Sandhill Crane has focused scientific attention on a wide range of topics relevant to crane conservation in general, including habitat management, dispersal patterns, effects of predators and pesticides, the role of disease, and loss of genetic diversity (USFWS 1991). Several recent studies (McIvor 1993, McIvor and Conover 1994, Bouffard in press) have examined the incidence and impact of crop depredation.

Drewien et al. (1995) provide a comprehensive review of recruitment data for the Rocky Mountain population of Greater Sandhill Cranes in comparison with other North American crane populations.

The Cuban Sandhill Crane represents the exception to the generally high level of scientific knowledge about the species. Cuban conservation biologists have had only limited funding, training, and personnel with which to work, and until recently only a few non-Cuban crane researchers have been able to gain access to areas where the cranes survive (Faanes 1990, Galvez and Perera 1995, E. Santana pers. comm., X. Galvez pers. comm.).

Population and Habitat Viability Assessment

A population and habitat viability assessment was conducted for the Mississippi Sandhill Crane in September 1992. Participants in the PHVA workshop offered a number of specific recommendations aimed at increasing the nesting success of the wild cranes, reducing the mortality rate of wild cranes, dividing the captive flock, and addressing health issues (Seal and Hereford 1992). A number of these recommendations have already been implemented. The CAMP for cranes has also recommended that PHVAs be conducted for the Cuban Sandhill Crane (pending the results of field surveys) and for the Okefenokee population of the Florida Sandhill Crane (Mirande et al. in press a).

Management and Recovery Plans

Management and recovery plans have been prepared for several Sandhill crane subspecies and populations. These plans are briefly summarized here.

Mississippi Sandhill Crane Recovery Plan

A recovery plan for the Mississippi Sandhill Crane was first developed in 1976, and has since been revised three times. The recovery objective, as stated in the most recent (1991) revision, is “to maintain a genetically viable, stable, self-sustaining, free-living Mississippi Sandhill Crane population.” In working toward this goal, the recovery plan lays out detailed conservation actions under six main categories:

  1. Develop population dynamics and minimum viable population models for the Mississippi Sandhill Crane.

  2. Restore, improve, and maintain nesting, feeding, and roosting habitats within the Mississippi Sandhill Crane National Wildlife Refuge.

  3. Increase recruitment, reduce mortality, and enhance heterozygosity.

  4. Monitor the response of wild cranes to habitat management actions.

  5. Review the potential for establishing one or more breeding populations within the historic range.

  6. Plan, update, and implement a comprehensive research program to address: (1) reduced natural recruitment, (2) loss of genetic viability, (3) tumor rate, and (4) habitat enhancement (USFWS 1991).
Management Guidelines for Mid-continental Sandhill Cranes (1981, 1990, 1993)

Under the auspices of the Central Flyway Waterfowl Council, a statement of Management Guidelines for Mid-Continent Sandhill Cranes was first developed in 1981, and has since been revised twice. The management goal, as stated in the most recent (1993) revision, is “to provide optimum diverse recreational opportunities consistent with the welfare of Mid-Continent Sandhill Cranes, international treaties, and socioeconomic constraints.” The guidelines describe actions to be taken in meeting three objectives:

  1. “A population index of Mid-Continent Sandhill Cranes within a range of 343,000-465,000 birds.”

  2. “Maintain the geographic and temporal distribution of Mid-Continent cranes similar to the 1982-1992 period.”

  3. “Maximize recreational use consistent with population and distribution objectives.”
Management Plans for the Rocky Mountain population of Greater Sandhill Cranes (1982, 1987, 1991).

A Management Plan of the Pacific and Central Flyways for the Rocky Mountain Population of Greater Sandhill Cranes was first developed in 1982, and has since been revised twice. The goals, as stated in the most recent (Smith 1991) revision, are to:

  1. “Maintain a stable population of 18,000-22,000... Greater Sandhill Cranes as determined by the most recent, accurate, spring census in the San Luis Valley, Colorado.”

  2. “Allow for expansion of current distribution where desirable.”

  3. “Maintain and protect sufficient habitats to support population and distribution objectives.”

  4. “Provide for recreational uses of the crane population.”
The plan recommends specific state-level management procedures involving habitat preservation, uses of cranes, depredation control, inventories, and research.

Cuban Sandhill Crane Research and Management Plan

As a result of recent contacts among Cuban, Mexican, and U. S. crane conservationists, efforts have begun to develop a comprehensive research and management plan for the Cuban Sandhill Crane. The initial objectives of the plan are to determine: (1) the status and distribution of the Cuban Sandhill crane; (2) the factors limiting its population; (3) daily and seasonal activity patterns; and (4) feeding and reproductive behavior (Galvez and Perera 1995). This information will provide the foundation upon which to base future conservation activities.

Non-governmental Organizations

The North American Crane Working Group has played a key role in focusing interest on the Sandhill Crane through regular workshops, publications, and other activities. The group hosted its seventh workshop in January 1996. Private conservation organizations, including The Nature Conservancy and the National Audubon Society, have also contributed to the protection of valuable Sandhill Crane habitat. For example, The Nature Conservancy played an instrumental role (beginning in 1974) in acquiring lands for the establishment and expansion of the Mississippi Sandhill Crane NWR (USFWS 1991). Important spring staging areas along the Platte River are held by TNC, the National Audubon Society, the Platte River Whooping Crane Habitat Maintenance Trust, and the State of Nebraska (Logan et al. 1976, Currier et al. 1985, VanDerwalker 1987, Strom 1993). ICF has focused on the Sandhill Crane in many of its education, research, training, and habitat protection and management programs.

Education and Training

As a wide-ranging, abundant, and easily identified species, the Sandhill Crane has been incorporated into many conservation education programs and projects, especially those focusing on wetland values, functions, and conservation. These include, for example, the annual midwestern crane count (see above), which not only provides data on the size of the population and status of habitat conditions, but allows participants to learn about crane and wetland conservation in the process (Dietzman and Swengel 1994). Annual crane festivals have been organized at several key staging and wintering grounds, including the Platte River staging grounds, the Buena Vista NWR, and the Bosque del Apache NWR.

In addition to the key role that Sandhill Cranes play in public education programs, they have also been used extensively for professional training in field research, captive propagation, and reintroduction methods. Practices that have been (or will be) applied mainly to other species have often been “tested” first on Sandhill Cranes. These include the development of techniques for isolation rearing and banding and migration studies. Sandhill Cranes are now being used in experiments to teach migration routes to captive-reared cranes (see the Whooping Crane species account).

Captive Propagation and Reintroduction

All five mainland subspecies are maintained in captivity, but only the Mississippi Sandhill Crane is being bred actively for reintroduction purposes. The others have been used in captivity in educational programs, as surrogate incubators for threatened species, and in research on captive rearing methods.

The GCAR for cranes inventoried the known captive populations of Sandhill Cranes (Mirande et al. in press a). Greater and Florida Sandhill Cranes are the most widely represented within the captive population. As of 1993, some 150 Greater Sandhill and 300 Florida Sandhill Cranes were known to be in captivity. They are generally easy to breed.

The Mississippi Sandhill Crane is the focus of an intensive captive propagation and release program. The U.S. Fish and Wildlife Service initiated the program at its Patuxent Wildlife Research Center (now the Patuxent Environmental Science Center) in 1966. The first fertile eggs were produced in 1973, and releases began in 1981. Since then, a total of 245 birds have been released. Approximately 75-80% of the birds at the Mississippi Sandhill Crane Wildlife Refuge are either captive-bred, or direct descendants of captive-bred, individuals (Valentine and Logan 1991, Ellis et al. 1992). As of 1994, Patuxent housed 17 breeding pairs. The captive flock at Patuxent is in the process of being split and transferred to two facilities, the White Oak Conservation Center in Tulee, Florida, and the Freeport-McMoran Audubon Species Survival Center in New Orleans.

Since 1993, wild-caught subadult Florida Sandhill Cranes have been translocated to the Grand Bay Wildlife Management Area in Georgia. This project aims to establish a non-migratory population in Georgia outside of the Okefenokee Swamp (Nesbitt 1994a).

There have been no systematic efforts to maintain and breed the Cuban Sandhill Crane in captivity.

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Priority Conservation Measures

In general, the Sandhill Crane’s conservation needs reflect the fact that the migratory populations are still abundant, and thus offer opportunities to prevent population declines, to bolster their recovery in areas where they have declined, and to anticipate potential conflicts between people and cranes. However, this will require an active, energetic program of population monitoring, habitat protection, policy incentives, and education.

For the G. c. canadensis-rowani-tabida complex, the most critical general conservation needs are (1) improved surveys of the breeding populations and (2) expanded habitat protection, management, and restoration of present and former spring staging areas along the Platte River, especially through education and watershed-wide habitat conservation programs.

For the non-migratory subspecies, the most important general needs are (1) effective management of remaining habitats, (2) restoration of degraded habitats and ecological processes (especially fire and hydrological cycles), and (3) effective reintroductions of the Mississippi (and potentially the Cuban) Sandhill Cranes.

The following specific conservation priorities relate to these general needs.

Legal and Cultural Protection

  1. Secure legal protection for the Platte River instream flow, and provide for protection, restoration, and maintenance of habitat within areas traditionally used by migrating Sandhill Cranes.

  2. Assess the need for separate listing of the Florida Sandhill Crane by the USFWS.
International Agreements and Cooperation
  1. Support continued international efforts to develop a conservation program for the Cuban Sandhill Crane (see below).

  2. Expand cooperation between biologists in Mexico’s Sandhill Crane wintering grounds and those working in the breeding range of these populations.
Protected Areas

Priority needs in this area are noted within several other categories in this section.

Habitat Protection and Management

  1. Protect instream flow in the Platte River.

  2. Protect and restore essential wetland and upland habitats of the non-migratory subspecies. This should include: acquisition and protection of additional habitats of the Florida Sandhill Crane to ensure that the range of the species remains contiguous throughout the Florida peninsula; securing of existing and potential habitats for the Mississippi and Cuban Sandhill Crane; and management of these habitats to maintain appropriate vegetation type and ecosystem structure and function.

  3. Protect and restore additional critical staging and wintering areas of the migratory subspecies, including: the seasonal playa lakes of western Texas; wet meadows and riparian roosting areas along the North Platte and Platte Rivers; wintering grounds of the Greater Sandhill Crane in Florida; wetlands of the intermountain west, California, and the American Southwest; and Laguna de Babicora and other wintering areas in northern Mexico (see Tacha et al. (1994) for specific needs in many of these areas).

  4. Promote conservation of habitats on private lands in the key migration and wintering areas of the migratory subspecies. Since much of the non-breeding (and, in the case of the Greater Sandhill Crane, breeding) habitat of migratory Sandhill Cranes is on private land, it is important that conservationists and private landowners collaborate in efforts to protect, improve, and restore wetlands, to exchange information, and to monitor and respond to crop depredation problems. Greater attention to trends in agricultural policy and agricultural practices, and their impact on habitat conditions, is needed. Cooperative agreements, easements, and other methods of habitat protection should be explored (see Smith 1991, Bouffard in press).
Surveys/Censuses/Monitoring

Priority needs in this area are noted within several other categories in this section.

Research

Research related to the rarer Sandhill Crane taxa should focus on:

  1. Population and habitat surveys and a conservation needs assessment for the Cuban Sandhill Crane.

  2. Continued studies of the factors behind poor reproduction and recruitment rates in the Mississippi Sandhill Crane population.

  3. Clarification of the intraspecific genetic structure and phylogenetic relationships among the Cuban, Florida, and Mississippi Sandhill Cranes.

  4. Quantitative analysis of the genetic distinctiveness and long-term viability of the (Okefenokee) population of the Florida Sandhill Crane.
Research related to more abundant Sandhill Crane taxa should focus on:
  1. Improved assessments of the size, status, and population dynamics of the mid-continental populations. In particular, research should: assess the accuracy of current survey techniques; assess the suitability of survey results as indices for the entire population; identify factors affecting the accuracy of surveys; develop alternative and/or supplemental means of monitoring; and determine the stability of annual recruitment rates.

  2. Clearer delineation of populations, migration routes, range expansions, and the relationships among subspecies along migration routes and in wintering grounds.

  3. Clarification of the intraspecific genetic structure and phylogenetic relationships among the G. c. canadensis-rowani-tabida group.

  4. Improved techniques for controlling and minimizing crop depredation.
Recovery of the Mississippi Sandhill Crane
  1. Fully implement the Mississippi Sandhill Crane Recovery Plan.

  2. Give special consideration, within the framework of the Recovery Plan, to the following:
Developing a Cuban Sandhill Crane Conservation Program

In order to protect and restore the highly endangered population of the Cuban Sandhill Crane and its habitats, a comprehensive conservation program needs to be developed and implemented. This program should include the following components:

  1. Development and implementation of an initial research and management plan.

  2. Thorough field surveys and assessments of existing populations, habitats, and threats. These are needed to provide the basis for further conservation planning.

  3. Establishment of a monitoring program to provide accurate assessments of trends in the populations and their habitats.

  4. Ecological research on historic and current crane habitat to provide management guidelines (especially for fire management), and to weigh the potential for restoration in portions of the historic range.

  5. Opportunities for collaboration and training involving Cuban and non-Cuban field ecologists, ornithologists, and conservationists.

  6. Development of an education program to communicate the importance, status, and conservation needs of the subspecies.

  7. Establishment, pending the results of thorough field surveys, of a captive propagation and reintroduction program.
Anticipating and Responding to Crop Depredation

Crop depredation by Sandhill Cranes is intermittent, and limited to certain geographic areas, crop types, and times of the year. This offers opportunities to conduct research, to anticipate future occurrences of damage, and to prepare effective responses. To do so, programs should focus on:

  1. Research to determine the timing and extent of the problem in different parts of the species’ range.

  2. Habitat management techniques (e.g., development of lure crops) to minimize potential damage.

  3. Extension and public education programs involving farmers.

  4. Research into the actual impact of hunting as a method of reducing depredation.

  5. Development of compensation programs and policy incentives to reward farmers whose management practices contribute to crane conservation.
Understanding the Impact of Hunting

The effect of hunting on Sandhill Crane populations has been a controversial topic. In order to provide a stronger scientific basis for understanding the impacts of hunting on crane populations (including the accidental taking of Whooping Cranes), for informing policy debates, and for making policy decisions, the following measures should be given high priority:

  1. Improve regular surveys to monitor trends in the populations of migratory Sandhill Cranes. Especially important are surveys of the Western and Gulf Coast wintering subpopulations of mid-continental Sandhill Cranes (see Tacha et al. 1994).

  2. Expand research on the effects of hunting on various populations and on the number and age structure of birds taken. Greater attention should be given to research on the long-term effects of disturbance from hunting on the distribution of the various migratory populations.

  3. Continue close monitoring of the legal kill, crippling losses, and poaching in areas of the U.S. and Canada.

  4. Improve documentation of the annual mortality from sport and subsistence hunting in Mexico and Russia, and from subsistence hunting in Alaska and Canada.

  5. Expand basic research to support management objectives. Key areas (as indicated above under “Research”) include more precise demographic studies of the mid-continental populations, delineation of subspecies/subpopulation distribution and migration routes, and clarification of intraspecific taxonomic relationships.

  6. Improve communication among Canada, the United States, Mexico, and Russia on the impacts of hunting on Sandhill Crane populations, and on hunting practices, regulations, and prohibitions.
Education and Training

Because Sandhill Cranes are well studied, conspicuous, widespread, and migrate over great distances, they present many opportunities for innovative education programs. Specific educational priorities include:

  1. Involving qualified students in crane counts and censuses, especially at important staging and wintering areas.

  2. Involving students in long-term monitoring programs for the non-migratory subspecies.

  3. Developing cooperative projects involving schools in Russia, Canada, the United States, and Mexico in the study of avian migration, using cranes as a model.

  4. Developing primary and secondary school curriculum materials that use Sandhill Cranes to communicate information about the biology, status, and conservation of the species, other crane species, and wetlands. This should include field studies that stress the role of cranes as wetland “umbrella” species (i.e., species whose conservation can provide protection for a wide range of species and ecosystem processes).

  5. Using present knowledge of crane social behavior to communicate lessons about the role of animal behavior in conservation.
Captive Propagation and Reintroduction
  1. Implement the following recommendations outlined in the GCAR and CAMP for cranes (Mirande et al. in press a):

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