The Whooping Crane, a symbol of national and international efforts to recover endangered species, has returned from the brink of extinction but remains at risk. In 1941, the species reached a low of 15 or 16 migratory individuals wintering in Texas (Boyce 1987) and 6 non-migratory birds in Louisiana. The Louisiana population did not survive.
All whooping cranes alive today (437 in the wild + 162 in captivity = 599 as of August 2011 [Stehn 2011]) are descendants of the small remnant flock in Texas in winter 1941-42. Although that population increased to 283 by winter 2011-12 (Stehn and Haralson-Strobel 2014), several factors, especially human development and long-term water issues on the wintering grounds, continue to place it in jeopardy.
Despite intense management efforts, the whooping crane remains one of the rarest birds in North America. Establishment of additional populations by reintroduction has so far been unsuccessful, although progress has been made in reintroduction methods. Because of the concern this species has generated, it is arguably one of the best-studied birds in North America. Within the United States, the Whooping Crane is listed as Endangered; recovery actions have been accomplished cooperatively by Canada and the United States, assisted by provincial and state agencies, nongovernment groups, and the private sector.
The common name of the Whooping Crane is probably derived from its Guard Call or Unison Call vocalizations. In the 1800s, this species was widespread but apparently never common in the tall- and mixed-grass prairie marshes of the north-central United States and southern Canada. It remains ecologically dependent on such inland freshwater wetlands and, in winter, on coastal brackish wetlands. The only remaining self-sustaining wild population nests in or near Wood Buffalo National Park in the Northwest Territories and adjacent areas of northeastern Alberta, Canada, and winters on the Texas coast of the Gulf of Mexico. Attempted reintroductions in the Rocky Mountains (migratory) and in Florida (non-migratory) were unable to produce self-sustaining populations and have been discontinued. Reintroduction of a population migrating between Wisconsin and Florida began in 2001 and met with initial success, but its future will depend on solution of persistent nest failure. In 2010 a fourth reintroduction, to establish a non-migratory population, began in Louisiana. As of June 2014, 164 birds are maintained in captivity: 152 at five captive propagation facilities (Patuxent Wildlife Research Center, Maryland; International Crane Foundation, Wisconsin; Calgary Zoo, Alberta; Audubon Species Survival Center, Louisiana; and San Antonio Zoo, Texas), and an additional 12 birds at seven display facilities (S. Zimorski pers. comm.).
This species is perennially monogamous and typically begins egg production at ages 3 or 4 years in the wild, but often not until ages 5 to 11 in captivity. Females usually lay a 2-egg clutch annually but seldom fledge more than 1 young. Both parents care for the young for 10 to 11 months, and young learn migration routes by following their parents. Wild birds may survive an estimated 25 years, captive birds 40 or more years.
The definitive historical reference on Whooping Cranes is Allen (1952). When that work was published, the species was nearly extinct and the nesting area of what was soon to be the only surviving natural population was unknown. Allen (1956) completed this foundation reference with a supplement after the nesting area was discovered in 1954. The joint Canadian-U.S. Whooping Crane Recovery Plan (CWS and FWS 2007) serves as an excellent reference on the species and updates recovery actions through 2005. Beginning in 1975, the crane conservation community has held regular conferences at intervals of approximately 3 years. The North American Crane Working Group (NACWG) was formally established in 1988 to organize these events and publish the resulting Proceedings of the North American Crane Workshop. The papers therein are peer-reviewed and cover all aspects of Sandhill and Whooping Crane conservation and biology. Additional information, especially updates on populations and research projects, appear in two newsletters, NACWG's Unison Call and the Whooping Crane Conservation Association's Grus Americana.