Differential migration in five species of raptors in central coastal California

Joshua M. Hull, Sarah Pitzer, Allen M. Fish, Holly B Ernest, Angus C. Hull

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Using data from 17144 hawks trapped during migration through the Marin Headlands in central coastal California, we evaluated the extent of differential migration within five species of raptors and compared our findings to those obtained at other raptor-migration sites in North America. This is the first description of patterns of differential migration for raptors migrating along the Pacific corridor, and the first investigation of differential migration in Red-shouldered Hawks (Buteo lineatus). We found that females migrated significantly earlier than males in Cooper's Hawks (Accipiter cooperii), Sharp-shinned Hawks (Accipiter striatus), hatch-year (HY) American Kestrels (Falco sparverius), HY Merlins (Falco columbarius), and HY Red-shouldered Hawks. In American Kestrels we found no difference in migration timing between AHY females and males or between adults and juveniles overall. Juveniles preceded adults in Sharp-shinned Hawks and Cooper's Hawks. We did not have sufficient samples of adult Red-shouldered Hawks, or Merlins, to compare migration timing among age classes. For Cooper's Hawks, Sharp-shinned Hawks, American Kestrels, Merlins, and Red-shouldered Hawks, our data agreed with the patterns of migration seen elsewhere in North America. Our description of the migration patterns in Red-shouldered Hawks provides a baseline for future comparisons with data from other migration sites.

Original languageEnglish (US)
Pages (from-to)50-56
Number of pages7
JournalJournal of Raptor Research
Issue number1
StatePublished - Mar 2012


  • age
  • differential migration
  • falcon
  • hawk
  • raptor
  • sex
  • timing

ASJC Scopus subject areas

  • Animal Science and Zoology


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