Timing of reproduction by red-tailed hawks, northern goshawks and great horned owls in the Kluane Boreal Forest of Southwestern Yukon ...

• Main Author: Doyle, Frank I.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Accipiter gentilis; Yukon
• Online Access: https://dx.doi.org/10.14288/1.0099513; https://doi.library.ubc.ca/10.14288/1.0099513

In this thesis I examine the timing of breeding in 3 raptorial birds, red-tailed hawks (Buteo jamaicensis), goshawks (Accipiter gentilis) and great horned owls (Bubo virginianus). Specifically, I test Lack's 1954 theory that birds typically begin to breed such that the young bird's greatest demand for food will coincide later with the greatest abundance of available prey. Lack's theory predicts that birds which successfully match the timing of breeding to the peak in prey fledge more young than pairs which do not. This study was part of the larger Kluane Boreal Forest Ecosystem Project (Krebs et al. In press). Detailed information on weather, prey density and timing of the peaks in prey availability was gathered annually. I examined the timing of breeding over 8 years (1989 - 1996) in an environment with both harsh winter weather and cyclic prey populations. The 3 species differ in both life history and morphology and yet share the same prey base for much of the year. These shared prey enabled me to explore ...