First-Year Dispersal of Golden Eagles from Natal Areas in the Southwestern United States and Implications for Second-year Settling

Abstract Knowledge of dispersal from natal areas by pre-breeding-age Golden Eagles (Aquila chrysaetos) in North America is sparse, though crucial for conservation planning. During 2010–2015, we used satellite telemetry to document movement behavior of pre-breeding-age Golden Eagles from the Colorado Plateau and Southern Rocky Mountains of the southwestern U.S.A. Here we report on (1) 1st-yr dispersal timing, distances, strategies, and survival; (2) influences of age, sex, nest-mates, and area of origin; and (3) progressive distancing from natal nests and coinciding space use, including overlap between individuals' home ranges at the end of their 1st and 2nd yr. Our dataset included 293,960 GPS fixes from 66 Golden Eagles monitored through at least the onset of dispersal. All dispersed at age <1 yr. Most (66.7%) initiated dispersal during 16 September–21 November (median = 22 October, 191 d after median hatch date). We could assign each of 60 eagles to one of four 1st-yr dispersal categories based on maxim...