Northern Goshawks (Accipiter gentilis) are large, non-migratory and widespread forest raptors. Their requirements for large tracts of forest for foraging and nesting conflicts with forest resource management activities like timber harvest. There is much interest in the effects of forest management on goshawks, and although several attempts to list populations in the West under the Endangered Species Act have been unsuccessful, they have illuminated the need for data concerning the population and genetic status of goshawks.

The objectives of my dissertation were to: (1) determine whether methods alternative to capture-recapture were feasible; and (2) evaluate genetic relationships among goshawks across their range. To address the first objective, I conducted two studies whose goals were to establish methods for non-invasive genetic capture-recapture studies. First, I examined the question of whether individual goshawks could be genetically "marked". I identified a set of five microsatellite genetic markers that when used together provided the necessary resolution to uniquely genotype 113 goshawks from the Kaibab Plateau, Arizona. Second, I determined that feathers molted at nest sites provided a non-invasive source of DNA for genetic capture-recapture studies. I found that tail feathers provided significantly more DNA than other feather types, but all feathers (large and small) were useful for generating unique genetic profiles.

To address the second objective, I examined the genetic relationships among 21 populations of goshawks from across a large portion of their geographic range. I used mitochondrial control region sequences from 315 goshawks to address questions concerning: (1) Pleistocene isolation; (2) post-glacial gene flow; (3) support for unique population segments; and (4) corraboration of geographic distribution of genetic lineages with clinal variation in size morphology. Goshawks were historically isolated into three glacial period populations (Pacific-Coastal, Southwest and Eastern), and have subsequently experienced post-glacial gene flow, which resulted in two unique zones of admixture among Intermountain Western populations. Goshawk populations were genetically differentited among five major geographic regions: California, Colorado Plateau, Arizona Sky Islands, New Mexico and a large group including the Rocky Mountains, Great lakes and Central Appalachian Mountains. The geographic distribution of five major haplogroups agreed with clinal variation in size morphology.