The world whooping crane population now stands at 319, the highest level of the century. Last summer 47 pairs nested in and around Wood Buffalo National Park in the Northwest Territories and adjacent Alberta. This population of 190 whoopers--the only self-sustaining, wild population--winters at Aransas National Wildlife Refuge on the Texas coast.
An 18-year effort to start another wild population in Idaho using sandhill cranes to incubate whooping crane eggs was discontinued in 1988. Eighty-five chicks were fledged and reared by sandhill cranes between 1975 and 1988, but the mature whoopers never paired. The four remaining birds from this flock winter in New Mexico's Rio Grande Valley. A third wild population of 31 birds survives in Kissimmee Prairie, Florida, south of Orlando. This population, which originated in 1993 from birds reared in captivity, is nonmigratory.
Captive populations include a flock of 29 at the International Crane Foundation in Baraboo, Wisconsin; 19 birds at the Calgary Zoo; 72 birds at the Patuxent Environmental Science Center; and two pairs at the San Antonio Zoological Gardens.
In the mid-1800s, more than 1,000 whoopers nested in prairie marshes of north-central U.S. and southern Canada. These birds wintered primarily in the tall grass prairies of southwestern Louisiana. Advancing human settlement, agriculture, and perhaps the impacts of disease and occasional hunting and specimen collecting reduced whooping crane numbers through the late 1800s and early 1900s; by 1941, fewer than 20 individuals remained.
The biology of whooping cranes works against their rapid recovery. They don't reach sexual maturity until 4 or 5 years of age. Usually just two eggs are laid but only one chick is fledged, and often just every two or three years. In addition, they are handicapped by nesting so far north where the ice-free season lasts only four months. Their long migration exposes them to a variety of hazards: predation, disease, illegal shooting, and collision with man-made obstructions, especially powerlines.
Whooping cranes migrating between Canada and Texas frequently stop in northeastern Montana. Although no birds were observed there in 1995, in 1994 two whooping cranes were seen near Fort Peck and one in Sheridan County. In addition, cranes from southeastern Idaho occasionally wander west of Yellowstone Park to the Centennial Valley and Red Rock Lakes National Wildlife Refuge. The last several years a single whooper has visited this refuge with a flock of sandhill cranes.