Success and Predation of Bird Nests in Grasslands at Valley Forge National Historical Park

Abstract

Abstract Populations of grassland birds are declining in the Northeast due to habitat loss and fragmentation. Fragmentation of grasslands can contribute to lower breeding success of grassland birds by altering local predator communities. Using miniature video cameras, I estimated nest success and identified nest predators in grassland fragments at Valley Forge National Historical Park in southeastern Pennsylvania. Estimated nest-success probability for Sturnella magna (Eastern Meadowlark) at Valley Forge was 0.25 (0.04–0.65, n = 7) and similar to estimates from the Midwest, but slightly lower than other studies in the Northeast. Nest success for Spizella pusilla (Field Sparrow; 0.77 [0.31–0.98, n = 8]) and Agelaius phoeniceus (Red-winged Blackbird; 0.48 [0.18–0.80, n = 10]) was higher than estimates from other studies. The local predator community identified at Valley Forge was less diverse than documented in other studies, with only 4 species depredating 8 of 25 monitored nests. The primary predator was ...