Examining carry‐over effects of winter habitat on breeding phenology and reproductive success in prairie warblers (Setophaga discolor)

Winter habitat quality can influence breeding phenology and reproductive success of migratory birds. Using stable isotope ratios of carbon (δ13C) from bird claws and red blood cells collected in Massachusetts, USA, we assessed if winter habitat occupancy carried over to affect prairie warbler (Setophaga discolor) breeding arrival dates, body condition upon arrival, pairing success, first-egg dates, and reproductive success. In two of three years (in 2011 and 2012, but not in 2013), after-second-year (ASY) males wintering in drier habitat, as indicated by enriched δ13C values, arrived later on the breeding grounds. Based on the North Atlantic Oscillation index, there was likely less rainfall in the Caribbean wintering grounds during the winters of 2011 and 2012 compared to the winter of 2013, suggesting increased winter rainfall in 2013 may have diminished the influence of winter habitat occupancy on arrival date. We did not find any effects of winter habitat on breeding season phenomena...