Meeting Abstract

P2-131   -   City living: Smaller territories and shorter communication distance in urban songbirds Simberloff, RA*; Phillips, JN; Danner, RM; Derryberry, EP; University of Tennessee, Knoxville, TN; Texas A&M University, San Antonio, TX; University of North Carolina, Wilmington, NC; University of Tennessee, Knoxville, TN rsimberl@vols.utk.edu

A wealth of studies demonstrate that urban noise can interfere with animal communication by masking acoustic signals, such as birdsong, yet the functional consequences of impaired communication are still not well understood. For example, although many bird species sing at higher amplitude in noise pollution, communication distance is still reduced in noisy urban soundscapes. Song is a long-distance signal which functions to attract a mate and defend a territory, so it stands to reason that a reduction in communication distance could negatively influence a male’s reproductive or competitive success. Here we examine the relationship between communication distance and territory size in white-crowned sparrows (Zonotrichia leucophrys) across an urban-rural gradient. We mapped the territories of male white-crowned sparrows at urban and rural sites across the San Francisco Bay Area, CA, and calculated territory size as the 95% utilization distribution using a movement-based kernel density estimator. We measured the amplitude of each male’s song as well as background and ambient noise levels on his territory, which we then used to estimate communication distance. Our findings suggest that both communication distance and territory size vary with noise levels along an urban-rural gradient, and that communication distance may be one factor influencing territory size. These findings strengthen our understanding of the link between communication and fitness-related consequences for the individual – a requisite next step in the study of urban birdsong.