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Stanislaus River Basin and Calaveras River Water Use Program
Threatened and Endangered Species Report - March 1995
Bay Delta and Special Water Projects Division, CA Dept. of Fish and Game
Bald Eagle
Haliaeetus leucocephalus
Listed as Endangered by the Federal Government and Listed as Endangered by the State of
California
Life History
This large eagle, known as our national bird, is a predatory raptor. It measures 30 to 43
inches in length with a wing spread of seven to eight feet. Adults may be readily identified by
their large white head and tail, long neck, short tail, massive yellow bill, and yellow legs and
feet. First year birds are mainly dark, including the head and tail, and may be easily confused
with the immature golden eagle as both of these young birds exhibit blotchy white on the
underwing. Due to the size of both the golden and bald eagle, they may also be confused with
the turkey vulture, however, the eagle has a flat-winged soar as opposed to the wings of the
turkey vulture which are held in a V shape.
Bald eagles nest in late fall (November) to winter (February). Two eggs are laid and
usually hatch in 35 days. It takes approximately 12 weeks for the young bald eagles to fledge.
Both parents assist in incubation and care of the eaglets.
The bald eagle is a permanent resident now restricted to breeding in Butte, Lake,
Lassen, Modoc, Plumas, Shasta, Siskiyou, and Klamath counties; approximately half the
wintering population is contained in the Klamath Basin. Elsewhere, this eagle is an
uncommon migrant.
The preferred foraging habitats of the bald eagle are rivers, lakes, estuaries with free-flowing
water, an abundant fish population, and suitable snags or perches (DeGraaf et al.
1980). These raptors consume a wide variety of food items, including 45 species of birds, 11
species of mammals, 12 species of fish, and five species of turtles. Although the staple of the
bald eagle is fish (DeGraaf et al. 1980), their prey may be classified into three main types: live
fish, live sea or water birds, and carrion. Their prey selection is dependent largely upon
availability.
Findings and Conclusions
The numbers of bald eagles have declined in the lower 48 states due to pesticides,
shootings, habitat loss, and human disturbance. However, in recent years this process appears
to be reversing.
Bald eagles were sighted mid-December in the canyon reach by CDFG biologists. The
foothill and canyon reaches represent wintering habitat for bald eagles and additional surveys
are needed prior to the initiation of any future project of the Stanislaus River.
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