Date of Graduation

1997

Document Type

Dissertation/Thesis

Abstract

This study was conducted in the Monongahela National Forest of West Virginia during the summers of 1995 and 1996 to assess the influence of two-age and clearcut timber management practices on breeding songbirds and invertebrates. Examination by guild (nesting, foraging, habitat, migratory) revealed little difference in breeding bird abundance among harvested and unharvested treatments, this is presumably due to the developmental stage of the harvested treatments (9-15-years post-harvest). Parasitism rates by Brown-headed Cowbirds (Molothrus ater) were generally low (8.66%). Most parasitized nests, however, were associated with two-age stands or the uncut forest adjacent to these stands. Cowbirds appeared to use the residual trees in two-age stands as perches to detect nest building activity within or adjacent to these stands. Thus, it is recommended that this type of timber management practice not be used near areas, such as cattle pastures, that are known to provide foraging sites for cowbirds. Mean total invertebrate biomass and litter dwelling invertebrate biomass was highest {dollar}(P \\le 0.05){dollar} in the unharvested treatment, while invertebrates that hide under tree bark during the day were most abundant (P = 0.003) in the two-age treatment. Invertebrate biomass did not have a significant influence on breeding bird abundance {dollar}(P > 0.05){dollar} but did significantly influence avian breeding success. Birds breeding in areas with a higher biomass of invertebrates had higher nest survival, generally advanced their laying date, their young grew at a faster rate and had a higher mass approaching fledging age, thus enabling them to fledge at a younger age. In addition, as with invertebrate biomass, daily nest survival rates (315 nests) tended to be highest in the unharvested treatment {dollar}(P \\le 0.05).{dollar} There also were significant positive correlations between invertebrate biomass and daily nest survival rates of breeding birds, suggesting that changes in invertebrate biomass due to silvicultural practices have an influence on breeding birds within these areas.

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