Lack of Differential Migration in Juvenile Merlins and Northern Harriers During Fall Migration in the Florida Keys

Abstract We used hydrogen stable isotopes in feathers collected from 1998 through 2003 to examine if there was differential migration of juvenile Merlins (Falco columbarius) and Northern Harriers (Circus cyaneus) through the Florida Keys, USA in fall. We examined differences by gender, population, and intra-season variation for 120 Merlins and 60 harriers. We found no difference in δDf values among years, and between genders, and dates of capture for either species.