Date of Graduation

2000

Document Type

Thesis

Degree Type

MS

Committee Chair

Robert C. Whitmore

Abstract

Gypsy moth defoliation can result in the death of trees and create snags (standing dead trees), a resource vital to cavity-nesting species. With this in mind, population trends of 11 cavity-nesting birds and their relationship to snags were investigated from 1984 to 1999 in an area that was impacted by gypsy moth defoliation. Data from before a major gypsy moth outbreak (1984-1986), during (1987-1988), and after (1989-1999) enabled inferences about this forest bird community to be made. The combined abundance of the 11 cavity-nesting species examined increased significantly during the years immediately after the outbreak (1989 – 1993) followed by a decline in the last 6 years (1994 –1999). The abundance of snags also increased significantly during the years immediately after the outbreak followed by a decline in the last 6 years. Regression analysis confirmed that cavity-nesting bird abundance increased as snag abundance increased. Nearly 79% of the snags created following the outbreak were oaks (Quercus spp.). Both bird abundance and snag abundance increased abruptly in 1988 immediately following the outbreak. These data suggest that snags may limit the populations of cavity-nesting birds and that cavity-nesters are able to take immediate advantage of a new population of snags.

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