Breeding biology of the golden eagle in southwestern Idaho

Publication Type:

Journal Article

Authors:

Beecham, John J.; Kochert, M. N.

Source:

Wilson Bulletin, Wilson Ornithological Society, Volume 87, Issue 4, p.506-513 (1975)

Call Number:

A75BEE01IDUS

URL:

https://sora.unm.edu/node/129229

Keywords:

Golden Eagle, Haliaeetus leucocephalus

Abstract:

The breeding biology of the Golden Eagle was studied along 240 km of the Snake River canyon, southwestern Idaho, from 1968 to 1971. A density of 1 eyrie per 73 km² (56 breeding pairs) was found in 1971, or one pair for every 5.8 km of river. An average of 2.1 eggs were laid per active nest, 1.3 young were hatched, and 1.1 young were fledged from 89 clutches from 1969 to 1971. Nesting success ranged from 61 to 70%. Forty-one of 129 (32%) eaglets died before fledging: 17 from possible heat prostration, 14 disappeared, and 10 from miscellaneous causes (including fratricide). Accounting for the deaths of 28 immature and adult eagles were: electrocution 43% (all immature birds), impact injuries 21%, and shooting 11%. Fourteen of 16 banded eaglets were recovered within 174 km of their natal nests, one from 644 km to the southwest, and one from 563 km to the southeast. A two-year-old bird was sighted 507 km northeast of the area. Dispersal appeared to be random in direction.