Worm-eating Warblers with more pine needles in their nests also had increased nest success. Nest success was not affected by vegetation other than the proportion of pine trees or leaf litter depth, both of which increased nest success. Ovenbirds were found more where there were more and larger trees but were negatively affected by the proportion of pines, whereas Worm-eating Warblers were more abundant when there were higher numbers of trees and more pines. During 2012–2015, we investigated the effects of forest characteristics, such as vegetative composition and ground cover, on occupancy and nest success. We detected significant declines for Ovenbirds in both datasets, but we found conflicting data for Worm-eating Warblers. In 2012–2014, we conducted point counts at locations previously surveyed in 1981–1983 and analysed Breeding Bird Atlas data from 1980–2013 to estimate long-term population trends of two declining ground-nesting warblers on the Eastern Shore of Maryland within the Atlantic Coastal Plain: the Ovenbird Seiurus aurocapilla and the Worm-eating Warbler Helmitheros vermivorum. Changes in forest size and composition can affect Neotropical migratory songbirds breeding in Eastern North America, leading to population fluctuations and declines.
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