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Photo by Larry Dalton and Laura Romin
Photo Copyright Larry Dalton and Laura Romin
Whooping Crane
Grus americana
NatureServe conservation status
Global (G-rank): G1
State (S-rank): SX
- Reason: Although this species occurred in Utah historically, it is not known whether it formerly bred in this state. The remaining member of an introduced group of individuals that summered in southeastern Idaho was last seen during 2001.
External links
General information
The whooping crane, Grus americana, is native to the eastern and central areas of North America. Due to a severe decline in whooping crane numbers in its native range, an artificially established whooping crane population was begun in the mid-1970s in the Rocky Mountain area. Whooping crane eggs were placed in sandhill crane nests, and the young were raised by sandhill cranes after the eggs hatched. These whooping cranes migrated with sandhill cranes through Utah, on a journey from nesting grounds in Idaho to wintering grounds in New Mexico, until early 2002, when the last of these whooping cranes is believed to have died. Whooping cranes are Federally listed as endangered, but the population that migrated through Utah was designated "nonessential-experimental."
The whooping crane can be found primarily in wetlands, but pastures and cultivated fields are also preferred habitats. Whooping cranes feed on invertebrates, including crabs and clams, grains, berries, and even vertebrates, including fishes, amphibians, and reptiles. The species breeds in early May, eggs hatch in about one month, and the average clutch size is two. Major threats to the whooping crane include loss of habitat (especially wetland habitat) and collisions with power lines.
Species range
Historically this species occurred naturally in at least northern Utah (e.g., Great Salt Lake), but whether it formerly bred in Utah is unknown. Most Utah observations of this species had been in Uintah County (Behle 1981, White et al. 1983, Cook 1984), although the species had been seen once in Cache County (Kingery 1982), once in Wasatch County, and once in Emery County.
Migration
Now migrates mainly through Great Plains from southern Canada and Dakotas south to Texas (arrives around mid-October). Introduced individuals migrate from Idaho (also Utah, Montana, and Wyoming) south primarily to central New Mexico (this population is headed for extirpation). Pairs or family groups begin northward migration early to mid-April. An 85,000 sq km area in Saskatchewan appears to serve as a premigratory staging area in fall, but there are no critical, traditional wetlands used elsewhere by migrants (Howe 1989). Spring migrants use Platte Valley during northward migration. See Howe (1989) for information on migration between Texas and Saskatchewan (distribution patterns of radio-tracked individuals differed greatly from distributions derived from opportunistic sightings). See also Johnsgard (1991) for details on spring and fall migration. An attempt to establish a nonmigratory population in Florida was underway in the early 1990s.
Habitat
This species has irregularly been seen in various types of wetlands (particularly marshes), as well as pastures and cultivated fields.
Food habits
During summer, feeds on insects, crustaceans, and berries; winter diet includes grains, acorns, wolfberry fruit, insects, crustaceans (e.g., blue crab, crayfish), mollusks (e.g., the clam TAGELLUS PLEBIUS and the snail MELAMPUS COFFEUS), fishes, amphibians, reptiles, marine worms (USFWS 1980, Hunt and Slack 1989). Blue crabs obtained from flooded tidal flats and sloughs dominate diet in Texas until January; then cranes move to shallow bays and channels to eat clams and an occasional crab (Matthews and Moseley 1990). Radio-marked migrants fed primarily in a variety of croplands (Howe 1989). Probes in mud or sand in or near shallow water, takes prey from water column, or picks items from substrate (Ehrlich et al. 1992).
Ecology
Population has exhibited 10-year periodicity (Boyce and Miller 1985, Dennis et al. 1991). Mated pairs and families establish and defend winter territories on coastal marshes in Texas. Breeding territories are very large, averaging 770 ha (Johnsgard 1991). Home ranges of breeding pairs in Canada were about 3-19 sq km (Kuyt 1993).
Reproductive characteristics
Breeding begins in early May. Pair mates for life. Both sexes, in turn, incubate 2, sometimes 1-3, eggs for 33-34 days. Nestlings are precocial. Young are tended by both adults, fledge when no less than 10 weeks old (no earlier than mid-August), remain with parents until following year (dissociate after arrival on breeding grounds). Sexually mature at 4-6 years.
Threats or limiting factors
No threats to this species are known.
References
- Biotics Database. 2005. Utah Division of Wildlife Resources, NatureServe, and the network of Natural Heritage Programs and Conservation Data Centers.
