The whooping crane (Grus americana) is a member of the Gruidae (crane family), one of a dozen in the bird order Gruiformes. With a wingspan of 7½ feet, the long-legged and long-necked crane is the largest bird in North American and one of the most striking birds in Texas. Its plumage is white with black, red, and white face colorings; black-tipped wings are usually visible only when extended in flight. Paleontological evidence of their presence in North American extends back more than one million years, and at one point they probably ranged from Utah's Great Salt Lake to the eastern United States seaboard and from Canada south to Mexico. In historic times their range has been much diminished under the pressures of hunting and agricultural reclamation of marshland nesting habitats. The principal surviving flock migrates from breeding grounds in Wood Buffalo National Park in Saskatchewan, Canada, to the Texas coast to winter on Blackjack Peninsula at the Aransas National Wildlife Refuge. The cranes begin arriving at Aransas in late October and remain until April. They are territorial birds, migrating in families and establishing territories of up to one square mile in the coastal marshlands of the refuge. There they feed on blue crabs, clams, and small fish, as well as berries, acorns, roots, and grains.
Although probably never abundant in Texas during historic times, the whooping crane was a common winter visitor mentioned frequently in reports of nineteenth-century travelers and naturalists. By 1900, however, population numbers were declining sharply and the species had largely disappeared from the Texas coast, with the exception of Blackjack Peninsula between St. Charles Bay and San Antonio Bay. In December 1937, acting on the executive order of President Franklin D. Roosevelt, the United States Bureau of Biological Survey, forerunner of the United States Fish and Wildlife Service, purchased the peninsula and transformed it into the Aransas Migratory Waterfowl Refuge (later the Aransas National Wildlife Refuge). At that time, only two flocks of whooping cranes remained. In addition to approximately fifteen cranes migrating between Canada and Texas, a small flock of fourteen cranes resided year-round in Louisiana. The latter flock was halved by a tropical storm in 1940. The remaining cranes disappeared over a few seasons, leaving only the flock at the Aransas refuge. With federal protection and increasing public education, the whooping crane began a slow recovery. After reaching a low of 15 birds in the winter of 1938–39, the flock increased to 30 in 1948–49, 74 in 1978–79, and 138 by 1989–90. Although the number of wild whooping cranes has increased significantly over the past fifty years, long-term recovery of the species remains uncertain. Attempts at captive breeding have met with only limited success to date, and the small Wood Buffalo-Aransas population is vulnerable to several potential threats. Migrating birds are occasionally lost to hunters, and others are killed when they accidentally fly into power lines and fences. Disease, extreme weather, and predation claim other birds, particularly the young. Loss of habitat to coastal erosion and the potential impact of a chemical spill in the heavily traveled Gulf Intracoastal Waterway adjacent to the Aransas refuge also pose concerns for the whooping crane's survival.