On July 12, 1995, the bald eagle was reclassified from endangered to threatened in the lower 48 states. It is the first and only Montana threatened or endangered species to be downlisted since the 1973 Endangered Species Act became law.
Bald eagle numbers, estimated at a quarter of a million in the lower 48 states before 1800, declined steadily throughout the late 1800s and early 1900s. Raptors at this time were regarded as vermin and shot on sight. The Bald Eagle Protection Act of 1940 increased public awareness and made indiscriminate shooting, poisoning, collecting, and trading of bald eagles illegal, stemming the decline for a time. Yet, the advent of DDT and related pesticides during World War II and their widespread post-war use soon caused eagle reproduction to plummet. In 1963, a National Audubon Society survey reported only 417 active nests in the lower 48 states.
After years of research, scientists determined that DDE, a breakdown product of DDT, accumulates in the fatty tissues of female eagles and impairs the calcium release necessary for eggshell formation. This induces thin shells and reproductive failure during incubation. These findings eventually led to the banning of DDT and related chemicals in the U.S. in 1972.
In 1978, bald eagles throughout the lower 48 states were classified as endangered, except in Michigan, Minnesota, Wisconsin, Washington, and Oregon, where they were designated threatened. Between 1984 and 1994, the number of known breeding pairs in the Pacific States Bald Eagle Recovery Region (Washington, Oregon, California, Nevada, Idaho, Wyoming, and Montana) increased from 479 pairs to 1,192 pairs. One-fourth of all the breeding bald eagles in the lower 48 states come from this region.
Delisting requirements for the region include: (1) a minimum of 800 nesting pairs; (2) an average reproductive rate of 1.0 fledged young per pair with an average success rate per occupied site of not less than 65%; (3) breeding population goals met in at least 80% of the management zones; and (4) stable or increasing wintering populations. These goals have been met in the Pacific states and, if conditions continue, it could be the first recovery region where the bald eagle is delisted.
In Montana the bald eagle population has clearly improved since listing. Between 1978 and 1995 the number of known breeding pairs increased from 12 to 166, well above the downlisting goal of 99 breeding pairs cited in the 1986 Bald Eagle Recovery Plan. A summer, 1995 survey found 196 viable nesting territories in Montana, placing the state seventh in the nation (behind Florida, Minnesota, Washington, Wisconsin, Michigan, and Oregon) in numbers of breeding bald eagles and eagles produced.
The Montana Bald Eagle Working Group, formed in 1982 and composed of representatives from federal and state agencies, tribes, universities, conservation groups, and private industry, has provided leadership at the state level. In 1994 the group developed a "Montana Bald Eagle Management Plan" to provide information and guide landowners and resource managers in conserving eagle habitat.
