Post-fledging Golden-winged Warblers require forests with multiple stand developmental stages

Abstract

ABSTRACT Our understanding of songbird habitat needs during the breeding season stems largely from studies of nest success. However, growing evidence shows that nesting habitat and post-fledging habitat often differ. Management guidelines for declining species need to be reevaluated and updated to account for habitat shifts that may occur across the full breeding cycle. The Golden-winged Warbler (Vermivora chrysoptera) is a declining songbird species for which best management practices (BMPs) are based overwhelmingly on nesting habitat. We studied stand-scale habitat selection by fledgling Golden-winged Warblers during May–July, 2014–2017, in 2 landscapes (2 yr of data for each landscape), 200 km apart in Pennsylvania. Across 4 yr, we radio-tagged and tracked 156 fledglings. We used discrete-choice models to evaluate habitat selection during 2 post-fledging time periods (days 1–5, days 6–28). Fledglings used a variety of cover types, but most telemetry relocations (i.e. 85%) occurred in forest in the stand initiation stage, stem exclusion stage, or mature forest upland. Fledglings primarily selected stand initiation forest during the first 5 days, but preferred habitats differed between regions during days 6–28 post-fledging. Fledglings in one landscape favored stands in the stem exclusion stage while fledglings in the other landscape continued to select stands in the initiation stage. Fledglings moved greater distances as they aged and dispersed ∼750 m by day 28 post-fledging. These findings suggest the need to update Golden-winged Warbler BMPs to account for the broader habitat needs of fledglings during the breeding season. In addition, these results indicate that regional studies of habitat requirements can help guide management of dynamic forest landscapes for birds. LAY SUMMARY Little is known about the post-fledging ecology and habitat requirements of many migratory songbirds. We used VHF radio-transmitters to track 156 fledgling Golden-winged Warblers (Vermivora chrysoptera) from two subpopulations in Pennsylvania, USA, and describe their movements, habitat use, and habitat selection. On average fledglings dispersed ∼750 m from nest sites by day 28 post-fledging with the maximum dispersal distance being 3.6 km. Fledglings used all cover types but 85% of relocations occurred in stand initiation, stem exclusion, or mature forest uplands. Habitat selection was directed primarily toward forest in the stand initiation stage, however fledglings in one landscape also selected for stem exclusion stands. Managers should consider promoting additional forest stand age class diversity (especially forest in the stem exclusion stage) in areas proximate to Golden-winged Warbler nesting habitat to provide the structure necessary for fledglings.