Diet of the golden eagle Aquila chrysaetos during the breeding season in Sweden

During a five-year period, 1975–1979, a total of 2881 prey individuals of 65 prey species were collected at 162 golden eagle nests from northern Sweden and from the island of Gotland. In northern Sweden birds are taken in higher numbers than mammals but calculated as weight the two categories are of equal importance, The main prey during the breeding season are capercaillie, black grouse, willow grouse, ptarmigan, mountain hare and reindeer fawns which together form 91% of the total food biomass. The capercaillie and the black grouse are taken more in the southern part of the coniferous region than in the northern. In contrast, in northern areas, reindeer fawns are more preyed upon than in the South, Ptarmigan and willow grouse are the most commonly captured prey species in mountain areas. The total number of reindeer fawns taken (dead and/or alive) by the Swedish golden eagle population during one summer is estimated at 600 individuals. On Gotland the golden eagles take mammals more often than in its northern distribution area. Rabbit and hedgehog arc the most important species.