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The golden-winged warbler (Vermivora chrysoptera) is an early successional Nearctic-Neotropical migrant songbird undergoing population declines range-wide. The Cumberland Mountains contain one of the southernmost populations where goldenwingeds occur in relatively high densities on old reclaimed surface mines. The three objectives of this research were to (1) describe the basic demography and habitat use of this population, (2) compare the demography of the Cumberland population to a population in Ontario, and (3) to model alternative land use scenarios and the impacts on both the golden-winged warbler and the cerulean warbler (Dendroica cerulean), another declining Nearctic-Neotropical migrant that occupies mature forests. Specifically, I modeled daily nest survival rate as a function of biologically meaningful covariates (Part 2) and the relative effects of habitat and demographic factors on territory size variation (Part 3) for the Tennessee population. There was some evidence of annual variation in nest survival rates and a decline throughout the nesting season, but I found little evidence that local habitat characteristics measurably affected nest survival. Territory size varied with the percent cover of vines and the number of snags. The single demographic factor related to territory size was nest success; birds with larger territories had a greater rate of nest success. I compared annual adult survival, fecundity, rate of population growth (λ), and mean time to extinction for Tennessee and Ontario populations (Part 4). Adult survival and fecundity were similar for the two populations such that predictions based on the theory of life history variation with latitude were not supported. Lambda estimates suggested that both populations were declining and I projected extirpation within 20-30 years without immigration. To further explore avian populations in the Cumberlands, I modeled coal mining, reclamation, and timber harvesting under a base-case scenario (as described by landowners and industries) as well as for alternatives that limited the amount of disturbance (Part 5). None of the scenarios were sustainable alternatives for cerulean and golden-winged warbler populations. My results suggest that future disturbances should be significantly limited to meet cerulean population goals and existing early successional habitat should be maintained and enhanced to sustain goldenwinged warbler populations. |
