Bald Eagles

Eagle Biology The bald eagle, like its more formidable hunting relative the golden eagle, is found throughout North America. But “Old Baldy” is more of an opportunist and can be found scavenging carcasses in the grasslands and deserts as well as fishing along the rivers, lakes and coastlines. A few bald eagles seasonally make a living hunting coots, waterfowl or gulls.The big concentrations of eagles are wintering birds scavenging the dead salmon carcasses of the north west rivers. Breeding bald eagles disperse over most of the coast and into the interior lakes and waterways right across North America. The Bald Eagle and its Relatives The white head and tail of the adult bald eagle easily distinguishes it from its own young or the golden eagle. The brown plumaged golden eagle can best be distinguished from the brown immature bald eagles by closely checking the feet. Golden eagles have feathers noticeably covering the legs and toes, while the tarsus of the bald eagle (the 4 inches above the feet) are featherless and scaley yellow. If you see any yellow leg the bird is a bald eagle. The bald eagle is primarily a fish feeder but the adults can effectively hunt ducks. However, whenever possible they take the easy route and are scavengers. Other large birds sometimes confused with the eagles are the California condor, the turkey vulture, the osprey or large buteo hawks such as the red-tail. Bald Eagle Nests Bald eagles nest under a great many circumstances. On remote islands where there are no ground mammalian predators — particularly human or canid—they will nest on the ground or on rock pinnacles. Where big conifer trees such as sitka spruce, Douglas fir or cedar are available, the eagles commonly nest in the upper canopy so that from the nest platform there is a good view over the surrounding territory. These nests, in spite of the annual additions of branches and greenery, seldom get more than three to five feet deep, due to the high wind exposure and vegetative rotting. Along rivers and lakes the eagles commonly utilize deciduous trees. Along the west coast these are usually black cottonwood. In these the narrow forked structure often results in the nest, which is constantly being added to, being several meters deep. When the accumulation of this nest material exceeds the annual decay the nest eventually topples the tree or breaks the supporting branches. An Eagle is Born The bulky nest has an inner cup of soft warm moss in which the one to three eggs are laid. Eaglet at seven days of age. His thin layer of white down offers little protection and the parent has to brood the chick most of the time for the first ten days. Proud and inquisitive at five weeks of age. Now the thick warm grey down protects the chick against cooler weather when both parents are off hunting. By eight weeks of age the chick’s body is nearly full size but the feathers have hardly started to grow. At nine weeks the body contour feathers start to break through and within a week the head is feathered and offers the chick some real protection from rain. Finally at 10 ½ weeks the eaglet has attained full size and the body wing feathers now have the large long bones on which to grow. At this stage the chick spends considerable time each day exercising its big wings in preparation of the first flight on the 12th week. For the first year of its life, the bald eagle has dark plumage. The feathers become mottled when the bird is two to three years old. Four year old birds show an imperfectly patterned white tail and still have dark feathers on the head. Finally, at five years, the adult displays the archetypal pure white head and tail that distinguishes the bald eagle from all other raptors. [Bald Eagle Home] [Eagle Biology] [Eagle Festivals] [Vancouver Area Eagle Nests] [Eagle Links] Copyright © 2003 Hancock House Publishers. All Rights Reserved.