Natal Dispersal Distance of Bald and Golden Eagles Originating in the Coterminous United States as Inferred from Band Encounters

Abstract We reviewed band encounter data for Bald Eagles (Haliaeetus leucocephalus) and Golden Eagles (Aquila chrysaetos) to estimate natal dispersal distances for both species in the coterminous United States (U.S.). We filtered band recovery data to focus on individuals banded as nestlings, encountered at ages old enough to be breeding, and encountered at times of the year when they may be at or near breeding or prospective breeding sites. Our final data set included 96 Golden Eagles and 878 Bald Eagles. Distances between banding and subsequent encounter sites for both species were lognormally distributed. We employed both traditional and Bayesian methods of analysis, and obtained similar results from both approaches. Bayesian analysis of banding data suggest a median natal dispersal distance of 69.2 (95% highest density interval [HDI]  =  63.5–73.1) km for Bald Eagles and 46.4 (HDI  =  36.0–55.2) km for Golden Eagles. Median natal dispersal distance for female Bald Eagles 78.3 was (HDI  =  35.4–128.6) ...