Date of Award

2011

Degree Type

Open Access Thesis

Document Type

Master Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Gary Ritchison

Department Affiliation

Biological Sciences

Abstract

Because Sharp-shinned Hawks (Accipiter striatus) are the most secretive of North America's forest-breeding raptors, little is known about their breeding biology, including their preferred nesting habitat. In 2009 and 2010, I searched 248 forest stands in Kentucky and found 11 nests, all located in pines (Pinus spp.). Nests were at a mean height of 18.6 ± 1.4 m in trees with a mean height of 23.7 m and mean dbh of 38.2 cm. Nests were in mixed coniferous/deciduous forests, with a mean canopy cover of 77.6%. Comparison of the characteristics of nest sites and randomly selected unused sites revealed significant differences (P = 0.021). Discriminant analysis revealed that five variables (foliage cover, mean tree height, basal area, percent deciduous canopy cover, and distance from edge) permitted the best discrimination between used and random sites. Sharp-shinned Hawks nested in areas closer to edges and in areas with denser stands of taller conifers and denser understory. All nests were in stands of young (~25-50 years), even-aged conifers about 18 to 25 m in height, with the dense cover provided by the conifers likely providing protection from predators. Nest sites were also close to edges where stands of dense pines transitioned into areas with more, shorter deciduous trees and less foliage cover than nest sites. These adjacent areas may have provided better foraging habitat for nesting Sharp-shinned Hawks because small birds, their primary prey, are more abundant in mixed stands than in the dense stands of conifers where they nested.

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