No abstract

No abstract

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 for second‐year (SY) males or females, but our sample sizes for these age/sex classes were relatively low. Although winter habitat quality influenced arrival dates of ASY males, there was no evidence that it affected reproductive performance, perhaps because of high rates of nest depredation in our system. Our study adds to a growing body of research that shows the influence of carry‐over effects can differ among species and within populations, and also can be modulated by other environmental conditions. This information enriches our understanding of the role of carry‐over effects in population limitation for migratory birds.

Numerous wildlife species are dependent on the creation and maintenance of early successional forests, yet little is known about the effects of habitat management on some threatened species. One such species is the eastern whip-poor-will (Antrostomus vociferous), a nocturnal bird of conservation concern. We examined the effects of heavy thinning, mowing, burning, and herbicide treatments on this species by conducting point counts and nest searches on a pitch pine-scrub oak (Pinus rigida-Quercus ilicifolia) barren in western Massachusetts, USA, between 2006 and 2013. Our point-count data showed that the abundance of calling birds was greater in managed shrublands such as scrub oak barrens and heavily thinned pitch pine stands, compared to closed-canopy pitch pine and deciduous forest. We found a high number of whip-poorwill nests (n ¼ 26) and roosts (n ¼ 59), which we located primarily within managed shrublands. We did not search for nests in closed-canopy forests, and we were unable to determine the extent of their use of the forest edge for nesting. Nevertheless, birds selected nest sites under residual deciduous trees within the early successional forests; therefore, canopy cover appears to be important for nest placement at the nest-patch spatial scale, but not necessarily at a broader scale. Nests were found in both dense and sparse understory vegetation; none were found in vegetation patches that were <2 years since treatment. Estimated nest survival was 63% through incubation (daily survival rate ¼ 0.977, n ¼ 21), consistent with other published studies of nightjars in the United States and Canada. Creating and maintaining open-canopy early successional forests in pitch pine-scrub oak barrens, with the retention of some residual deciduous trees, should increase the amount of habitat suitable for courtship, roosting, and nesting by eastern whip-poorwills. Ó 2016 The Wildlife Society.

No abstract