Whooping Crane (Grus americana)

Whooping Crane

[order] GRUIFORMES | [family] Gruidae | [latin] Grus americana | [UK] Whooping Crane | [FR] Grue blanche | [DE] Schreikranich | [ES] Grulla Trompetera | [NL] Trompetkraanvogel

Subspecies

Monotypic species

Physical charateristics

A large white crane with a red face. Primary wing feathers black. Young birds are washed with rust color, especially about the head.

Listen to the sound of Whooping Crane

[audio:http://www.aviflevoland.nl/sounddb/W/Whooping Crane.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 220 cm wingspan max.: 240 cm
size min.: 140 cm size max.: 160 cm
incubation min.: 29 days incubation max.: 31 days
fledging min.: 78 days fledging max.: 90 days
broods: 1   eggs min.: 1  
      eggs max.: 3  

Range

North America : Central. Grus americana declined from historic estimates of 10,000+ prior to European settlement of North America to 1,300-1,400 birds by 1870 to 15 adults in 1938. The three wild populations totalled 382 in December 2007, including two reintroduced populations in the eastern U.S. that are not yet self-sustaining. The only natural wild population breeds in Wood Buffalo National Park, on the border of Northwest Territories and Alberta, Canada, and winters at and near Aransas National Wildlife Refuge, Texas, USA. It totalled a record 266 birds in 2007, with 65 active nests. A reintroduced, non-migratory flock in Florida numbered c.41 individuals in 2007, with additional releases put on hold. A reintroduced flock migrates between Wisconsin and Florida, numbering 75 birds in 2007. The first wild born chick fledged in Wisconsin and migrated successfully in 2006. Captive flocks totalled 148 birds in 2007 at 5 breeding centers and 6 display facilities in the USA and Canada.

Habitat

Muskeg (summer); prairie pools, marshes.
Current breeding habitat is in remote northern forest, in areas of muskeg (swampy coniferous woods with numerous lakes and ponds). Formerly also nested in prairie marshes. Winters in coastal marsh, where adult pairs and families defend territories, returning to same territory each winter.

Reproduction

In courtship, pairs “dance,” leaping into air repeatedly with flapping wings, bills pointed upward; dance has a dignified look. Other displays include bowing, tossing tufts of grass in the air, and loud trumpeting or “whooping” calls. Nest site is on ground, typically on marshy island in lake or pond. Nest (built by both sexes) is a large mound of grass, weeds, mud, with depression at center.
Eggs: 2, sometimes 1 or 3. Olive-buff, spotted with dark brown. Incubation is by both sexes, 29 -31 days; female usually incubates at night. Downy young leave nest within a few hours after hatching. Both parents feed young. Two eggs typically hatch, but very rarely or never does more than one young bird survive. Young able to fly at about 3 months after hatching.

Feeding habits

Omnivorous. In winter, eats insects, shrimp, crabs, clams, snails, frogs, snakes, small fish, seeds, acorns, roots, berries. Summer diet not well known, probably a similarly wide variety of animal and plant matter. Forages by walking slowly on land or in shallow water, searching for food visually or probing in mud.

Conservation

This species is listed as Endangered because it has an extremely small population. However, the conservation status of the species is improving, with not only increases in the natural wild population but also establishment of two reintroduced flocks that may become self-sustaining. If the number of mature individuals continues to increase, this species may merit downlisting to Vulnerable.
Over-hunting, habitat conversion and human disturbance were the main causes of the decline. Currently, the most significant known cause of death or injury to fledglings is collision with powerlines, and in 2007 a lightning strike during severe weather killed 17 young birds being housed in a top-netted release pen in Flordia. Pre-fledged eggs and chicks are subject to predation (raven, bald eagle, wolf, black bear, lynx). Powerline markers can reduce collisions by 50-80 percent, but most power lines remain unmarked and collision is a major and growing problem. The anticipated placement of thousands of wind turbines in the migration corridor will decrease availability of crane stopover habitat and may also dramatically increase the number of power lines. Drought is detrimental to all habitats utilized year around, but is especially harmful by dramatically lowering production on the nesting grounds. Coastal development, sea level rise, climate change, chemical spills, reduced fresh water inflows, and human disturbance threaten the Texan wintering grounds. Aransas NWR can only support a maximum of 500 birds through the winter and falls short of the initial downlisting target of 1,000 birds. Continued population growth may force some cranes in future to use disturbed and suboptimal habitat. Much of the currently unoccupied crane habitat at Aransas where the cranes would be expected to expand into is being threatened with construction of homes. There are currently concerns about oil spills and about river inflows to Aransas National Wildlife Refuge, and the spread of West Nile virus and avian influenza in the future may pose a threat to the species. The long-term effects of genetic drift after a severe population bottleneck are unknown.
Whooping Crane status Endangered

Migration

Breeds in Wood Buffalo Park
border of northern Alberta and Northwest Territories; migrates through Great Plains to coastal Texas. Reintroduced at Gray’s Lake, Idaho (migrating via Colorado to Bosque del Apache Refuge in New Mexico); also in Osceola County, Florida (non-migratory).
iEndangered but slowly increasing. bMigration:
Migrates by day, in family groups or small flocks. Travels along rather narrow corridors and makes traditional stopovers. Route is learned, not instinctive; young birds must learn it from parents.

Distribution map

Whooping Crane distribution range map

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