At more than five feet tall with brilliant white plumage, black primary feathers, a red cap, and yellow eyes, the highly endangered Whooping Crane (Grus americana) is one of the most spectacular birds native to North America. In 1942 there were fewer than 20 birds in the flock that migrates from Wood Buffalo National Park in Canada to Aransas National Wildlife Refuge in Texas. An additional six cranes were alive in Louisiana, bringing the total global population to only 22 individuals. The non-migratory Louisiana flock died out a few years later; hence all Whooping Cranes now alive derive from a core flock of only 16 birds. Whooping Cranes were likely uncommon even before hunting and habitat loss reduced them to dangerously low numbers. The vanishingly small population of 16 in 1942 represents an extreme genetic and demographic bottleneck that few species survive.
Biologists at the USGS Patuxent Wildlife Research Center began what is now the largest Whooping Crane captive breeding program from 12 eggs collected from the wild in 1967. The Patuxent flock now has over 60 adult Whooping Cranes, including 29 pairs, who lay an average of 40 eggs each breeding season.Patuxent biological technicians raise over 30 chicks each year. The majority of the chicks are released in Louisiana to join the non-migratory flock of Whooping Cranes. The remaining chicks are trained to follow an ultra-light aircraft on migration from Wisconsin down to Florida and become part of the migratory flock of Whooping Cranes.