EFFECTS OF VEGETATION, INTERSPECIFIC COMPETITION, AND BROOD PARASITISM ON GOLDEN-WINGED WARBLER (VERMIVORA CHRYSOPTERA) NESTING SUCCESS

Abstract

Abstract The recent decline of Golden-winged Warblers (Vermivora chrysoptera) correlates with the loss of suitable nesting habitat, range expansion by Blue-winged Warblers (V. pinus), and eastward expansion of Brown-headed Cowbirds (Molothrus ater). Multivariate statistics were used to examine effects of those factors on Golden-winged Warbler reproduction in north central New York. Herb and shrub cover were positively correlated with clutch size. Blue-winged Warbler proximity was negatively correlated with Golden-winged Warbler clutch size. Tree cover and perhaps herb cover, after adjusting for brood size, correlated with a reduced number of Golden-winged Warbler fledglings. Herbaceous cover correlated with a greater number of cowbird eggs in Golden-winged Warbler nests. Cowbird parasitism correlated with a reduction in the number of Golden-winged Warbler eggs incubated and proportion of incubated eggs that hatched. However, cowbird parasitism, after adjusting for brood size, did not significantly affect ...