New York Natural Heritage Program
Kentucky Warbler
Geothlypis formosa (Wilson, 1811)
Birds

Threats [-]
Forest fragmentation is perhaps the greatest threat to Kentucky Warblers. Southern New York, in particular the Lower Hudson River Valley, is currently under high development pressure. In areas where forests are more fragmented, brood parasitism from Brown-headed Cowbirds increases which can greatly decrease reproductive success. High White-tailed Deer populations may greatly reduce the amount of dense, low vegetation that this species needs during the breeding season. If predator populations (such as raccoons and snakes) are high there may be an increased risk of nest failure. Threats at wintering grounds may also be contributing to the decline of this species in the state.

Conservation Strategies and Management Practices [-]
Land managers should promote the growth of dense, low vegetation in the forest understory. Deer management may be needed if deer over-browsing is a problem. Contiguous, moist forests are ideal for Kentucky Warblers to reduce brood parasitism by Brown-headed Cowbirds.

Research Needs [-]
More research is needed to determine the minimum area required for a breeding pair, reproductive success, and effects of deer over-browsing in New York.