Meeting Abstract

P3.109  Thursday, Jan. 6  Repeatable nest defense behavior in a wild passerine BURTKA, J. L.*; GRINDSTAFF, J. L.; Oklahoma State University jay.burtka@okstate.edu

Eastern Bluebird (Sialia sialis) adults may be injured or killed when competing with an invasive passerine, the House Sparrow (Passer domesticus) for access to nesting sites. Both species utilize similar habitats and readily nest in nest-boxes. Eastern Bluebirds defend occupied nest-boxes against competitors, although the intensity of their response varies among individuals. We tested the repeatability of Eastern Bluebird nest defense behavior against House Sparrows within individuals with multiple breeding attempts in 2009 and 2010. We also compared nest defense behavior between years for Eastern Bluebirds that were captured in both 2009 and 2010. Females captured in 2009 demonstrated repeatable behavior whereas males defended less intensely over the duration of the breeding season. Although nest defense behavior was repeatable for both sexes in 2010, neither sex was repeatable across both sample years. There was no difference in behavior between second-year and after second-year adults. This suggests that nest defense behavior is more consistent within years compared to between years. These findings support previous research on avian personalities or behavioral syndromes that have demonstrated the repeatability of behavior in laboratory tests across one season. However, this is one of the first studies to examine repeatability both within and between years in wild individuals responding to a natural threat. Wild populations of Eastern Bluebirds may alter their behavior from year-to-year based on environmental or individual conditions but are most consistent in their behavior within years.