Meeting Abstract

P2.132  Tuesday, Jan. 5  The Effect of Nest Microhabitat on Reproductive Success of the Mountain White-crowned Sparrow KLAASSEN VAN OORSCHOT, B*; CRINO, O; BREUNER, C; University of Montana brett.klaassenvanoorschot@umontana.edu

Local environmental factors may influence nest success in many bird species. We compared nest site characteristics to fledging success and chick size in the Mountain White-crowned Sparrow (Zonotrichia leucophrys oriantha) at Tioga Pass, California. In this population, sparrows nest on the ground as well as in branches of small pines and willows. These site-specific environmental factors may present selective pressures on nestlings, but the consequences of nest habitat on nestling growth and fledging success are largely unknown. The Mountain White-crowned Sparrow provides an ideal opportunity to look at the affect of nest site characteristics on nest success because of the large variation in nest location in this species. We quantified nest microhabitat by measuring relative vegetation counts and density, above-ground water, and nest aspect. We found that environmental factors around the nest affected nestling size, but did not affect fledging success.