Masters Theses

Date of Award

12-2017

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

David A. Buehler

Committee Members

Joseph D. Clark, Craig A. Harper

Abstract

Golden-winged Warbler (Vermivora chrysoptera) populations in the Appalachian Mountains have declined precipitously over the past 50 years. To better understand the decline, I studied two important aspects of the reproductive cycle: the nesting and post-fledging periods on reclaimed surface mines and recent timber harvest sites at North Cumberland Wildlife Management Area (NCWMA), Tennessee from 2013 to 2015. Nestlings were radio-marked with a 30-day transmitter two days before their scheduled fledge date and monitored daily once they fledged. Vegetation data were collected at the nest site and daily fledgling locations points along with paired random points. Vegetation characteristics most important during nest site selection were percent mature forest within 250 m of nest (selected against), percent Rubus spp. within 1m of nest (selected for) and vertical vegetation density (selected for). Fledglings did not select for or against any vegetation types during their first 3 days post-fledging. Shrub/sapling vegetation was most selected for during days 4-25. Fledglings avoided mature forest vegetation and herbaceous vegetation during the same time period. Nest survival over a 23-day nesting cycle was 0.354 ± 0.058 (SE) across all years. Vegetation characteristics most closely related to daily nest survival were percent forbs within 1 m of nest (positive relationship) and percent Rubus spp. within 1 m of nest (negative relationship). Fledgling survival for the entire 25-day post-fledging period was 0.289 ± 0.066, with most of the mortality occurring in the first 3 days (0.736 ± 0.039 daily survival rate). Snake predation accounted for 52% (16/31) of known deaths. The best supported model when individual habitat covariates were added included percent shrub-sapling vegetation within 250 m of post-fledging location (negative relationship). All other individual covariates had a delta AICc >2 when compared to the top model. Managing for Golden-winged Warbler reproduction must be a balance between meeting the needs for nesting and ensuring fledgling survival. Compared to values reported elsewhere across the northern parts of the breeding range of the species, full season productivity at NCWMA of 0.66 offspring/pair may be insufficient to sustain populations without significant sources of immigration.

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