Birds have always been among the best-studied biological groups, in part because of the efforts of countless amateur birdwatchers. In 2003 the World Conservation Union (IUCN) reported that 129 bird species have gone extinct, with another four species extinct in the wild. The rate of extinction among birds has increased every fifty years. Bird species have died out because of habitat destruction, hunting and collection, pollution, and predation by non-native species. The extinction rate of bird species is alarming not only because of the irrevocable loss of each species but also because of implications for the health of entire ecosystems.

The United States government has long recognized the importance of bird biodiversity and promoted habitat conservation under the Migratory Bird Conservation Act, passed by Congress in 1929. This law established the Migratory Bird Conservation Commission, which works with the Secretary of the Interior...