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Bald Eagle
Haliaeetus leucocephalus
Order
FALCONIFORMES
– Family
ACCIPITRIDAE
Authors: Buehler, David A.

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Introduction

Adult Bald Eagle, striking at prey; Alaska, February
Immature Bald Eagle (Sub-adult I), Utah, January
Figure 1. Distribution of the Bald Eagle.

This species account is dedicated in honor of Eric Jolly, member of the Cornell Lab of Ornithology's Administrative Board.


Selected as the national emblem of the United States in 1782 by Congress, in spite of Benjamin Franklin’s arguments that the Wild Turkey (Meleagris gallopavo) would serve better in that capacity, the Bald Eagle has long been a key symbol in the human cultures of the Americas; feathers and body parts of this species have shown up regularly in archaeological investigations of Native Americans (Miller 1957). More recently, the species has served as a symbol of freedom associated with democracy in the United States and, in recent years, with wilderness and the environmental ethic.

The Bald Eagle is a large bird of prey with broad wings for a flapping-soaring flight and a characteristic white head and white tail in adult birds. The species is an opportunistic forager that eats a variety of mammalian, avian, and reptilian prey, but generally prefers fish over other food types. It often scavenges prey items when available, pirates food from other species when it can, and captures its own prey only as a last resort.

The Bald Eagle has undergone dramatic population fluctuations over the past two centuries. Often reported as abundant by early explorers of North America, the species was especially common in areas with large expanses of aquatic habitat, including Florida, Chesapeake Bay, Maine, and the Maritime Provinces of Canada, the Great Lakes and lake regions of Ontario, Manitoba, and Saskatchewan, the Pacific Northwest, including northern California, Oregon, Washington, and coastal British Columbia and Alaska. It was so abundant in Alaska that a 50¢ bounty was established in 1917, increasing to $2 in 1949 before the bounty was overruled by federal regulation in 1952. Over 128,000 bounties were paid out between 1917 and 1952 (Robards and King 1966). The bird became rare in the mid- to late 1900s in the contiguous United States as persecution by humans greatly reduced survival and pesticides, primarily DDT, significantly lowered reproduction. The species was listed for protection under the Bald Eagle Protection Act in 1940 and the southern subspecies was listed as Endangered in 1966 under protection of the Endangered Species Preservation Act. The entire Bald Eagle population in the contiguous United States was listed for protection in 1978 under the Endangered Species Act of 1973. Populations have increased dramatically since 1980 as DDT levels dropped and breeding productivity returned to pre-DDT levels across many parts of the range, and as human persecution decreased with increasing environmental awareness. This recovery represents one of the continent’s most successful conservation stories. Bald Eagles in the late 1990s had breeding populations in all Canadian provinces and all but 2 of the contiguous U.S. states (Rhode Island and Vermont), and a limited breeding population in Mexico.

This is one of the most studied North American birds, with well over 2,000 individual articles on various aspects of its biology and management. Significant research includes works by Herrick (1924, 1932, 1933, 1934), on nesting habits; Bent (1937) detailed basics on life history; Broley (1947, 1958) documented population declines in Florida; Anderson and Hickey (1972) linked population declines to eggshell thinning from DDT; and Grier (1982) documented population recovery post-DDT. Two excellent contemporary books on the species by Stalmaster (1987) and Gerrard and Bortolotti (1988) provide many details on the life history of the Bald Eagle.