(Errington 1930; Glading, Tillot- 

 son, and Selleck 1943). It has 

 merit in that it permits detection 

 of seasonal fluctuations in the food 

 of the same group of birds with no 

 individuals being removed from tlie 

 environmental complex. On the 

 other hand, the examination of pel- 

 lets, even more so than that of 

 stomachs, fails to reveal those items 

 that are readily obliterated in the 

 digestive process; and also, when 

 flesh, devoid of hair, fur, or bones, 

 is being ingested, pellets may not 

 be formed. This may happen when 

 the eagle is feeding on large car- 

 casses, yet Murie (1914) found in 

 Mount McKinley National Park, 

 that pellets ejected by golden eagles 

 frequently revealed evidence of the 

 birds having fed on the bodies of 

 caribou calves and Dall sheep — 

 construed to have been carrion. 



Still another method of food ap- 

 praisal of the golden eagle involves 

 the inspection of food remnants 

 found in or under nests or in the 

 vicinity of perches frequently used 

 by the birds. Through frequent 

 collecting of freshly deposited ma- 

 terial, a picture of seasonal fluctua- 

 tion in food may be obtained by this 

 method. On the other hand, ac- 

 cumulations of food debris over a 

 period of years may have the picture 

 confused by the fact that other crea- 

 tures, particularly packrats {Neo- 

 totna) may add to or detract from 

 the accumulation. 



The foregoing recital sets forth 

 some of the problems faced by the 

 student of the economy ~ of wild 

 creatures. The science is fraught 

 with many difficulties; it also has 

 many reassuring and coiiviuciiiir 



characteristics, not the least of 

 which is an adequate and intimate 

 field acquaintance with the creature 

 being appraised. In his analysis, 

 the author has endeavored to make 

 use of all approaches available to 

 him. 



FOOD HABITS 



The American golden eagle is 

 both a predator and a carrion eater, 

 and at times it takes carrion even 

 though live food is available. Like 

 most widely ranging species its food 

 varies from place to place depend- 

 ing on availability. 



Indicative of the golden eagle's 

 adaptability are the following items 

 which have been reported eaten by 

 this species. These lists were com- 

 piled from the literature and from 

 field records of the United States 

 Fish and Wildlife Service. 



Among the birds taken are 

 herons, swans, geese, ducks, turkey 

 vultures, accipitrine hawks, Buteo 

 hawks, marsh hawks, falcon s, 

 grouse, ptarmigan, European par- 

 tridge, quail, pheasants, wild tur- 

 keys, coots, plovers, curlews, band- 

 tailed pigeons, owls, kingfishers, 

 magpies, ravens, crows, and various 

 smaller perching birds. 



Mammals listed as taken by the 

 golden eagle include opossums, 

 moles, raccoons, ring-tailed cats, 

 martens, weasels, minks, skunks, 

 foxes, coyotes, bobcats, woodchucks, 

 ground squirrels, prairie dogs, 

 arboreal stpiirrels, pocket gophers, 

 native rats and mice, muskrats, por- 

 cupines, ])ikas, varying hares, jack- 

 I'abbits. cottontails, deer, elk, cari- 

 bou, i)rongli()ni antelope, mountain 

 sheep, and mounlain goats. 



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