Editorial Office, Steroids and Hormonal Science, Germany
Short Communication
During the Nestling Period, Testosterone and Heterospecific Aggression were
Observed In Adult Eastern Bluebirds (Sialia sialis)
Author(s): Jennifer Stewart*
Conspecific competition is thought to have a stronger selection effect on aggressive behaviour and its underlying physiology in birds than the heterospecific competition. We hypothesised that the hormone-behaviour interaction between testosterone and aggression could be influenced by severe heterospecific competition among secondary cavity nesters. Adult Eastern Bluebirds (n=34) were subjected to three challenge conditions that simulated territorial intrusions (STI) by heterospecific (House Sparrow) and conspecific (Bluebird) using live and stuffed decoys and their respective playback vocalisations. Late in the nesting cycle, Eastern Bluebirds responded to simulated territorial intrusions (STIs) by Conspecific and heterospecific. When compared to homospecific STI, the aggressive response elicited by a heterospecific STI was muted. Individuals with high aggression levels had slightly h.. View More»
