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.. View More»
