In the Central Appalachians, the Kittatinny Ridge is a key autumn migration corridor for eastern raptors. I studied migrating raptors during autumn along the Kittatinny Ridge. My objectives included to assess the frequency of travel and stopover in individual raptors and document behavior during stopover to understand the role and importance of stopover in migration in raptors. I also studied which habitats were used by raptors during stopover and the frequency of use of the Kittatinny Ridge to determine the importance of habitat to raptors and whether a flyway corridor could be identified.

In one part of the study, I radio-tagged and followed 34 Sharp-shinned (Accipiter striatus) and 14 Cooper’s Hawks ( A. cooperii) during autumn migration 2003 and 2004. Birds were trapped on the Kittatinny Ridge, and followed for one to 12 days each through Pennsylvania and neighboring states. Both species spent 1-5 days on stopover between travel periods (mean= 2 d.). Sharp-shinned Hawks spent an average of 33.6% of daylight foraging (+ 24.5 SD) and 32.6% of day roosting (+27.4), and Cooper’s Hawks spent 33.8% (+ 6.8) of day foraging and 47.2% (+26.2) roosting. Sharp-shinned Hawks spent less time roosting than Cooper’s Hawks; however, neither species differed in behavior by age, except that adults spent more time in non-migrating flight. The ratio of hours in travel to hours on stopover per bird during tracking was 1:7 (including night hours) suggesting that rest and foraging periods are an integral aspect of their migration journey.

Forest patch size was one of the most important factors in stopover site selection with both species choosing larger forests more than occurred at random at both the landscape scale and near scale. At a regional scale, both species selected more rural areas for stopover sites, selecting areas with more mixed forest and pasture. Sharp-shinned Hawks avoided suburban areas as well. Hatch-year Sharp-shinned Hawks used contiguous forest, wetlands, and evergreen forest less than adults. Nearly half of all roosts of both species were on the Kittatinny Ridge suggesting either an affinity to large forests or the flyway itself. Both species combined roosted at an average of 6.9 km from the ridge flyway when found within the Ridge and Valley region. Hatch-year birds roosted farther from the ridge than adults in both species and Sharp-shinned Hawks roosted farther from the ridge than Cooper’s Hawks.

Cooper’s Hawks were more selective in their habitat choice during migration than during nesting, choosing large forests in more rural landscapes. The selection of roosts by Sharp-shinned Hawks near wetlands may indicate that the opportunity to drink is important during migration or that wetlands concentrate their songbird prey. Evergreen stands could provide important protective cover to roosting Sharp-shinned Hawks, as they may be more vulnerable to avian predation and more likely to seek out evergreen forest during stopover than the Cooper’s Hawk.

During road surveys of all raptors on stopover, birds were most abundant within 1 to 6 km of the ridge and less numerous farther from the ridge or on the ridge itself. The lowest abundance was observed at the farthest distance from the ridge, 16 km. The pattern of higher abundance near the base of the ridge remained consistent regardless of changes in forest cover. The abundance near the Ridge indicates that distance to the flyway could be an important factor influencing migrant distribution. Habitat influenced distribution of migrants on stopover as well. Forest raptors were more numerous on the north side where forest cover was more abundant, and open habitat raptors, e.g. Redtailed Hawk and Northern Harrier, were more numerous on the south slope where farmland predominates. Although age influences patterns of migration, no age difference was observed in habitat or distance of migrant raptors surveyed during road surveys. (Abstract shortened by UMI.)