Bald Eagle

ZOO LOCATION: Rocky Mountain Wild

Lifespan: Over 30 years in the wild

Wild Diet: Fish (especially salmon) some live, but usually dying or dead fish are taken; they will also take crippled waterfowl.

Zoo Diet: Dead rodents, chicks and fish

Predators: Raccoons and great horned owls for nestlings and eggs.


IUCN Status: Least Concern

Habitat/Range: Along coasts, rivers and lakes in North America

Characteristics: Adult has white head and white tail; immature lacks white areas and is easily confused with golden eagle; adult plumage is not completely attained until 4 to 5 years.

Behavior: Bald eagles are only partially migratory. If they have access to open water they will stay at that site year-round.

Reproduction: Bald eagles are monogamous and mate for life. The pairs will build large nests, called eyries, and will return to the same nest year after year. The female will lay one to three eggs in the springtime which will hatch after a 35 day incubation. The parenting duties are shared by both parents.

Conservation: Historically bald eagles lived throughout North America. Populations started to decline in the early 1900s due to illegal shooting, nest damage, prey loss, lead poisoning, pesticides and loss of habitat. Though the Bald Eagle Protection Act was passed in 1940, the species continued to decline. By 1963 biologists believed there were less than 500 wild pairs remaining in the lower 48 states and only a few nesting pairs in Colorado. As a result, bald eagles were listed as endangered in most of the U.S. by 1967. The passing of the Endangered Species Act in 1973 allowed the U.S. Fish and Wildlife Service to broaden their captive breeding, reintroduction and protection efforts.

Bald Eagles have made a slow recovery from near extinction. Through the efforts of federal and state agencies and conservation groups, their populations had recovered in the lower 48 states to an estimated 4,500 pairs in 1995, allowing them to be down-listed from endangered to threatened. In 2001, there were an estimated 51 breeding pairs of bald eagles in Colorado alone. Over the next seven years, their population increased to over 10,000 individuals. By 2007, they had recovered enough to be taken off the Endangered and Threatened Species List all together. Colorado is now a very popular wintering area for bald eagles. The annual midwinter count shows stable populations of up to 800 eagles. The San Luis Valley in the southern part of the state is one of their favorite places because of its supply of fish and waterfowl as well as its high populations of rodents and rabbits.

Although they were removed from the Endangered and Threatened Species List, bald eagles are still protected under the Bald and Golden Eagle Act and the Migratory Bird Treaty Act. These laws make it illegal to harm eagles, their nests and their eggs. Following their delisting, the U.S. Fish and Wildlife Service will continue to work with the Colorado Division of Wildlife and other state agencies across the nation to monitor bald eagle populations for a minimum of five years, as required by the Endangered Species Act. If the species should need protection again in the future, they can be relisted as endangered or threatened.