Migrant Forest Songbirds Undertake Breeding Dispersal Following Timber Harvest

Abstract

We report two observations of breeding dispersal by migratory songbirds, Dendroica caerulescens (Black-throated Blue Warbler) and D. fusca (Blackburnian Warbler), from their initial territory locations following timber harvest. Forty-eight birds of each species were captured and marked as part of a long-term study on warbler survival in the Greater Fundy Ecosystem, NB. None of the birds banded in unharvested patches were re-encountered in other patches. Maximum movement distances for the displaced Blackburnian Warbler and Black-throated Blue Warbler were 1.3 km and 2.9 km, respectively. These are the longest breeding-dispersal distances reported for these species. Our paper provides the first direct evidence that birds may move once their breeding site has been altered due to timber harvesting. Potential conservation implications are discussed.