Effects of phenology and territory intrusion on Carolina Wren behavior

• Kara Taylor, Wildlife Ecology and Conservation, University of Delaware

• Greg Shriver, Entomology and Wildlife Ecology, University of Delaware

The Carolina Wren (Thryothorus ludovicianus) has one of the most diverse song repertoires in the Avian order Passeriformes. The many vocalizations of this species come with a wide range of functions, including locating young, alerting mates of danger, and deterring conspecific males. Territory defense is among the most common reasons for Carolina Wrens to sing or call. The objectives of this project are to record Carolina Wren songs during the breeding season to estimate singing phenology and determine wren responses to experimental territorial intrusions. 20 autonomous recording units (ARUs; AudioMoths) have been deployed in Newark, DE and north into White Clay Creek Preserve, PA. The ARUs record audio for four hours a day, from March through September. Once the breeding season ends, I will examine the influence phenology has on wren singing behavior using the ARU recordings and a bioacoustics analysis software known as Kaleidoscope. From mid June to early August, I biked to each ARU location and performed territorial intrusions in order to analyze how Carolina Wrens exhibit aggression and territoriality. These intrusions were conducted in one of two ways; either vocally or vocally and visually. Vocal intrusions consisted of a playback recording taken from a wren at a different ARU location being played. Vocal and visual intrusions included a decoy Carolina Wren mount that was positioned alongside the speaker playing the recorded song. The immediate, 10 minute responses to these intrusions were recorded on a data sheet, and the delayed, 72 hour responses are analyzed using Kaleidoscope. The analysis of this project’s results will take place this upcoming fall semester. I predict that Carolina Wren singing rates will increase after a territory intrusion was performed. I also hypothesize that male Carolina Wren primary songs will decrease in frequency over time as the breeding season ends.