Northward Summer Migration of Red-Tailed Hawks Fledged from Southern Latitudes

Abstract

Abstract With a breeding range extending from approximately 68°N in northern Canada to 8°N in Panama, Red-tailed Hawks (Buteo jamaicensis) exhibit migrations that vary substantially with latitude. Northern populations are almost completely migratory, middle-latitude populations are partially migratory, and southern populations south of 38°N are considered sedentary. Contrary to the latter widely held belief, we found that many juveniles and young adults from one population below 38°N are also partially migratory. However, unlike most birds in the northern hemisphere that migrate south in autumn, young Red-tailed Hawks from our southwestern California study area migrated north in summer to summering areas as far as 1462 km from their natal nests. Of the 5271 Red-tailed Hawk nestlings we banded in the study area and an additional 189 banded by other researchers, 205 were encountered (found dead or alive or recaptured) outside the study area. We classified 64 encountered hawks as potential migrants, most (69...