Correlates of aggression : the interplay between boldness, testosterone, and territoriality in male song sparrows, Melospiz melodia, in urban and rural habitats

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
James Kyle Boudreau (Creator)
Western Carolina University (WCU )
Web Site:
Jeremy Hyman

Abstract: Animals colonizing urban habitats are often noticeably bold in the presence of humans, and such boldness is typically thought to arise as urban individuals habituate to the repeated presence of humans. However, recent studies in animal behavior suggest that: 1) boldness may be an inherent trait as opposed to a learned behavior and 2) some individuals exhibit behavioral syndromes that restrict behavioral plasticity, and may limit an individual’s ability to adapt to environmental change. In a recent study, we examined differences in urban and rural populations of song sparrows and confirmed that urban birds were bolder toward humans, but also, this boldness was correlated with higher levels of territorial aggression. This study also examined the correlation between testosterone, a hormone associated with aggression in birds, and variation in aggression and boldness in urban and rural song sparrows (Melospiza melodia). Despite significant differences in aggression and boldness between urban and rural populations, this study found no evidence of differences in testosterone between the two populations. It is possible that other mechanisms (e.g. sensitivity to circulating testosterone) may be involved, and further examination into these possibilities will provide better understanding of these behavioral differences.

Additional Information

Language: English
Date: 2011
behavioral syndrome, territoriality, testosterone, urban
Song sparrow -- Behavior -- North Carolina
Song sparrow -- Territoriality -- North Carolina
Song sparrow -- Habitat -- North Carolina
Aggressive behavior in animals -- North Carolina

Email this document to