Meeting Abstract

P1.8  Sunday, Jan. 4  Why springs song is winters new friend: effects of urbanization on the American robin (Turdus migritorius) SCHULER, Matthew S.*; LIMA, Steve L.; Indiana State University; Indiana State University matt.s.schuler@gmail.com

Global climate change is a growing concern among scientists and the general public. Despite this concern, most researchers have failed to account for the effects of local factors on climatic variation and its consequences for the distributions of species. We studied the effects of urban environments on the winter distribution of the American robin. We analyzed data across a latitudinal gradient (25N to 65N) for 230 randomly selected cities in North America. Average densities were based on the data from the Christmas Bird Count between 2006 and 2008. A regression analysis was used to determine whether the size of the human population affected the number of overwintering robins. Slopes from latitudinal groups were analyzed starting at 25 to 30, ending with 60 to 65 to see if there was a greater city size effect in northern latitudes. From our analysis, we concluded that larger cities affect overwintering populations in northerly climates, because larger cities maintain higher densities of robins during winter than small cities. Yet, this phenomenon was not observed in southerly cities. Based on this analysis, researchers should consider local environmental change when predicting the effects on global change on the densities and distributions of organisms.