An investigation of cliffs and cliff-nesting birds in the southern Appalachians with an emphasis on the Peregrine Falcon

• Main Author: Watts, B. D.
• Format: Text
• Language: unknown
• Published: W&M ScholarWorks 2006
• Subjects: peregrine falcon
• Online Access: https://scholarworks.wm.edu/ccb_reports/379; https://scholarworks.wm.edu/context/ccb_reports/article/1378/viewcontent/ccbtr_06_14_Watts_An_investigation_of_cliffs_and_cliff_nesting_birds_in_the_southern_Appalachians_with_an_emphasis_on_the_Peregrine_Falcon.pdf

The peregrine falcon was believed to be extinct in the southern Appalachians as a breeding species by the early 1960s. Despite extensive recovery efforts made over the past 30 years, the status of breeding Peregrines within this portion of the historic range remains virtually unknown. The primary objective of this study was to conduct a survey of cliffs within the southern Appalachians for bird species with an emphasis on the Peregrine Falcon. A systematic aerial survey of cliffs and cliff use by birds was conducted throughout a significant portion of the southern Appalachian Mountains covering nearly all of the mountains of Virginia a small portion of Kentucky, and the spine of the Appalachians in West Virginia. During the course of helicopter flights, 242 exposed rock surfaces were mapped, characterized, and surveyed for bird use. Cliffs had a combined length of 122.4 km and a combined area of 470 ha. More than 25% (118 ha) of the collective rock surface that was mapped was occluded by vegetation. The surface area of 75 (31%) cliffs was estimated to be occluded by at least 50%. There was a relationship between cliff height and the level of occlusion. Cliffs that are greater than 30 m high are significantly less likely to be occluded by more than 30% corresponding to the maximum height of local tree species. A total of 97 (40%) of the surfaces mapped were estimated to be higher than 30 m with 13 (5.4%) exceeding 100 m. Eleven bird species were observed using cliff faces during aerial surveys. Birds were either roosting/loafing (941, 92.6%) or nesting (75, 7.4%). Cliffs appear to represent prominent roosting sites within the landscape for several bird species. Vultures were observed roosting on 124 (51.2%) of the 242 cliffs surveyed with an additional 54 (22.3%) cliffs with characteristic whitewash. Nests of 5 species were detected on cliffs including Common Ravens (35), Turkey Vulture (2), Peregrine Falcon (1), Red-tailed Hawk (1), and Great Horned Owl (1). Common Ravens and Red-tailed Hawks built stick nests ...