Endangered Species Act - Experimental Populations

In 1982, the ESA was amended to allow the reintroduction of experimental populations of threatened or endangered species into their historic ranges without requiring compliance with many of the act's restrictions (§ 1539 (j)). Currently designated experimental populations are listed in the Code of Federal Regulations (see 50 C.F.R. §§ 17.81–.82). As of March 2003, 35 species were designated as experimental populations, including the red wolf and the gray wolf. The experimental population designation relaxed existing ESA regulations by allowing reintroduced species to be managed or controlled; for example, ranchers could kill reintroduced wolves that threatened livestock.

In the 1990s, the federal government began a program to restore an experimental population of gray wolves to Yellowstone National Park and central Idaho. The program projected the transfer of 90 to 150 Canadian gray wolves into Yellowstone National Park and central Idaho over three to five years. In early 1995, 29 gray wolves from Canada were released into Wyoming and Idaho. The release of the experimental population of gray wolves was controversial and created conflict and lawsuits between environmentalists and livestock ranchers. The goal of the wolf recovery program was to remove wolves from the endangered species list by 2002. This did not happen. As of March 2003, the gray wolf remained listed as a "dual status" species (both threatened and endangered) but delisted status was pending, based on taxonomic revisions.