Shrubland birds are disturbance dependent species and are experiencing population declines of 1–3%/year rangewide. In our study, we determined nest success rates of four shrubland species, Blue-winged Warbler (Vermivora pinus), Prairie Warbler (Dendroica discolor), Indigo Bunting (Passerina cyanea), and Field Sparrow (Spizella pusilla), at Bent of the River Audubon Center, Southbury, Connecticut, USA. Field sites were conservation-managed fi elds that were actively managed for shrubland specialists. Data were collected on 123 nests (May–August, 2004–2006) and nest success rates (calculated using the Mayfi eld method) were 0.37 ± 0.003 for Blue-winged Warbler, 0.35 ± 0.013 for Prairie Warbler, 0.65 ± 0.009 for Indigo Bunting, and 0.50 ± 0.014 for Field Sparrow. Our study of these species is one of only three from the New England/ Mid-Atlantic Coast Region. We compiled data from studies from all regions reporting nest success of these species, conducted in a variety of managed and unmanaged shrublands. We compared our results to these studies and found nest success rates in conservation-managed fi elds to be similar to or higher than studies in different habitat management types in different regions. Based on our comparision of results from the limited number of studies on nest success rates of shrubland birds, the rotational mowing, selective tree removal, and invasive plant control regimes used to maintain conservation-managed shrublands are effective management practices to maintain high to moderate rates of nest success and may even be preferable to other management practices where shrubland species are targets for conservation.
Project Report: Nest Success Rates of Four Shrubland Specialists in Conservation-managed Fields with Comparisons to Other Managed and Unmanaged Shrublands