Mass changes and energetic condition of grassland and shrubland songbirds during autumn stopovers at a reclaimed landfill in the New Jersey meadowlands

Abstract

ABSTRACT Former landfills have long been recognized as a potential source of early successional habitat for wildlife, but their use by migrating grassland and shrubland songbirds has yet to be studied. We estimated mass change rates of 5 grassland and shrubland songbird species during autumn stopovers at a reclaimed landfill in New Jersey, to assess the quality of a former landfill as a stopover habitat. We also examined minimum length of stay, age ratios, and age differences in body mass and fat scores. Regressions of capture time and body mass were statistically significant and indicated gains of 0.8–1.2% of average body mass per hour in Savannah Sparrows (Passerculus sandwichensis), Lincoln's Sparrows (Melospiza lincolnii), and Palm Warblers (Setophaga palmarum), but coefficients of determination were weak (<0.06). White-crowned Sparrows (Zonotrichia leucophrys leucophrys) and Indigo Buntings (Passerina cyanea) did not gain significant mass. Minimum length of stay based on recaptures ranged from an ave...