Towering 1.5 m (5 ft) above the ground, a Whooping Crane is the tallest bird in North America. It is equally impressive in flight: the wings span 2 m (6.5 ft.), black primary feathers sharply contrast against its snow-white plumage, and its long legs trail behind.
Red on the crown and lower cheek, and a large bustle (curved plumes that hang down over the tail) are also distinctive. Apart from being larger and heavier (7.3 kg versus 6.4 kg; 16 vs. 14 lb.), male cranes are similar to females. Whooping Cranes are long-lived; some captive birds have reached 40 years of age.
Whooping Cranes are named for their loud, single-note calls, which are greatly amplified by a coiled trachea that stretches 150 cm (nearly five feet). These calls are given when a crane is frightened and during aggressive interactions (these are known as guard calls), or during courtship (unison calls). Courtship is a visual extravaganza replete with wing flaps, head throws, and spectacular metre-high (3 ft.) leaps.
Whooping Cranes are omnivores and their diet includes berries, grains, insects, snails, minnows, frogs, snakes, mice and voles. On the wintering grounds, they eat mainly crabs and clams. Cranes nest on mounds in shallow wetlands, and their two eggs take up to 35 days to hatch.
In the mid 1800s, the Whooping Crane population was estimated at approximately 1400, and by 1970, the species was one of the rarest in the world. After years of bordering on the fringe of extinction, the Whooping Crane population is growing, largely because of protection, and captive breeding and release programs.
In 2008 there were 146 Whooping Cranes in captivity and 377 wild birds in three distinct populations. Of these wild populations, the largest and only self-sustaining one consists of 266 birds that nest in Wood Buffalo National Park and winter along the Gulf Coast in the Aransas National Wildlife Refuge area. A second wild population is a re-introduced Florida population that contains 37 birds. The third is the Eastern Migratory Population; it was established in 2001, and totals 74 birds.
Because migration in cranes is a learned behaviour, the Eastern Migratory group was led from release sites in Wisconsin to wintering sites in Florida by ultra-light planes flown by biologists dressed as cranes.