Grus americana (Linnaeus 1758)

Whooping cranes are monogamous and generally mate for life, once they have reached sexual maturity at three to five years of age (6). These birds undertake a spectacular migration of over 4,000 kilometres from summer nesting grounds in the north, to winter feeding grounds in the south (5). As the days get longer and spring approaches, the flock on the winter site becomes restless; dancing, calling and flying before family groups and pairs finally begin the journey north (6). Birds arrive at the breeding area in April and pairs return to the same nesting territory over consecutive years. Generally a clutch of two eggs is laid although only one chick is usually reared to maturity (5). Both parents take part in incubating and rearing the chick, which hatches after roughly one month (5). In September, the first individuals leave for the return migration south as the cold begins to set in (5). These birds are omnivorous, feeding on a range of wetland species. Preferred winter foods include blue crabs and clams, whilst in the summer aquatic invertebrates, small fish, frogs and berries may be consumed (6). During migration the birds primary source of food is waste grain in agricultural fields (5).

The whooping crane has been the subject of an enormous, broad-based conservation effort since the mid-20th Century, involving the United States and Canadian Wildlife Services, together with other organizations such as the Patuxent Wildlife Research Center and the International Crane Foundation (7). The multi-faceted approach has involved the protection of important habitats, the monitoring of populations and a captive breeding program. The establishment of an additional migratory population was attempted in Idaho but has not proven successful (10). However, greater progress has been achieved with the setting up of a non-migratory population in Florida, which now numbers 86 individuals (11). Another attempt at establishing a migratory population was begun in 2001, with birds being taught a migration route from Wisconsin to Florida behind ultra-light aircraft (9). The main captive populations exist at Patuxent Wildlife Research Centre, the International Crane Foundation and Calgary Zoo and have been used in these reintroduction attempts (10). These efforts have increased the wild population of these elegant birds from just 21 in the 1940s to about 300 today, a truly fantastic achievement (11).

Whooping cranes represent one of the best-known conservation stories in North America and these elegant birds have captured public imagination. Whooping cranes have almost entirely white plumage, with the exception of red and black markings on the face and black tips to the wings, which are only visible when out-stretched (5). Juveniles are a reddish-cinnamon colour, becoming mottled over time until the full snow-white feathers are achieved by the end of their second summer (6). These cranes are the tallest birds in North America, and males may reach up to 1.5 metres in height (5). When flying, the neck is stretched out in front and the thin, black legs trail behind (5).

The main population of whooping cranes is migratory; the summer nesting grounds are poorly drained wetlands, whilst the population overwinters in salt marshes in the south (5) (6).

Previously, whooping cranes were found over much of North America, from the Arctic coast in the north to central Mexico, and from Utah in the west to New Jersey and Florida (6). By the mid-20th Century however, the migratory population had declined to just 16 individuals and the non-migratory population in Louisiana had disappeared completely (7). Following a massive conservation effort, a self-sustaining population exists today, breeding in Wood Buffalo National Park, Canada and spending the winter in the Aransas National Wildlife Refuge on the Texas Gulf Coast (8). A non-migratory population has also been introduced to Kissimmee Prairie in Florida (6) and a migratory population is currently being established that will summer in Wisconsin and winter in Florida (9).

Classified as Endangered (EN) on the IUCN Red List 2007 (1). Listed on Appendix I of CITES (3), and Appendix II of the Convention on Migratory Species (CMS or Bonn Convention) (4).

The original decline in whooping crane numbers followed the drainage and clearing of wetlands, together with other human disturbances in the breeding areas and migration routes (10). Shooting for food by early settlers and specimen collection for museums and egg collectors wreaked havoc on the remaining population. Today, cranes remain at risk from human development (10); collisions with power-lines are now a serious cause of mortality (6). Moreover, the single population is at risk from any chance event and conservationists are particularly fearful of a chemical spill in the Gulf of Mexico that would destroy the wintering grounds in Texas (6).