Population Genetics of Red-Tailed Hawks
Migrant North American bird species are of particular conservation concern due to threats including habitat degradation, contaminant poisoning, and exotic diseases (DeGraaf and Rappole 1995, Rappole 1995). Conservation efforts are hampered by a poor understanding of where birds go after they leave summer breeding grounds, and enter migratory routes and wintering grounds that may be important sources of exposure to environmental contaminants and pathogens, leading to significant mortality (Canavelli et al. 2003).
For several species, information is available about population structure on the breeding grounds, but data describing population structure away from breeding grounds is lacking (Rappole 1995). Thus, it is a priority to characterize the composition of bird groups on migratory flyways and wintering grounds with respect to breeding populations. Knowledge of where specific populations winter and the migration routes they use may allow identification of population-specific risks (Hobson 1999). Molecular genetic tools provide a powerful means of accomplishing this task (Lovette et al. 2004).
Red-tailed Hawks (Buteo jamaicensis) are well suited as a model species for investigation of connectivity between breeding populations and wintering and migratory regions. Red-tailed Hawks breed across North America providing sufficient geographic scope (Preston and Beane 1993). In western North America, Red-tailed Hawk morphology has been associated with broad habitat types suggesting distinct population structure may exist on the breeding grounds (Fitzpatrick and Dunk 1999). Further, Red-tailed Hawks are studied in large numbers during autumn migration and winter, providing an opportunity to obtain sufficient samples for assignment to particular breeding populations.
In collaboration with numerous raptor researchers and wildlife rehabilitators, the Wildlife and Ecology Unit is currently investigating the population genetic structure of Red-tailed Hawks in western North America. Using a combination of molecular tools (mtDNA sequence and nuclear microsatellites) we hope to determine if population structure among western Red-tailed Hawks exists and, if so, how populations distribute themselves throughout the year.
- Hull J.M., W. Savage, J.P. Smith, N. Murphy, L. Cullen, A.D. Hutchins, H.B. Ernest. In press 2007. Hybridization among Buteos: Swainson's Hawks (Buteo swainsoni) × Red-tailed Hawks (Buteo jamaicensis). The Wilson Journal of Ornithology.