Breeding season forest fragment size does not create negative carry-over for adult Wood Thrushes on fall migration timing or apparent annual survival

Although carry-over effects related to wintering habitat quality are known to influence population dynamics of migratory songbirds, the presence of breeding season carry-over is under-studied in full annual cycle models. To test whether forest fragment size on the breeding grounds can impose negative carry-over effects on a migratory songbird, we fitted adult Wood Thrushes with one-year coded radio-tags in forest fragments ranging from 11­–499 ha in southwestern Ontario during the 2016–2019 breeding seasons and utilized automated telemetry via the Motus Wildlife Tracking System to record fall migration timing and returns the following spring (apparent annual survival). To examine short-term effects of fragment size on breeding females, during the 2018 and 2019 breeding seasons, we collected blood samples during incubation to measure corticosterone levels and tracked complete reproductive success and nest timing. We found that Wood Thrushes breeding in small forest fragments were not sub..., During the 2016–2019 breeding seasons (May-August), adult Wood thrushes (Hylocichla mustelina) were captured in a variety of forest fragments in southern Ontario, Canada. Each bird that was captured had mass, tarsus length, wing length, age, and sex recorded. During 2018–2019, some birds were blood sampled to evaluate levels of corticosterone, the stress hormone in birds. During all years of the study, some birds were tagged with coded radio transmitters and fall migration dates and apparent survival were recorded using the Motus Wildlife Tracking System, which is an automated telemetry array. Vegetation surveys were conducted at each location that a bird was tagged., The datasheet can be opened using Microsoft Excel or R.