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Territory Holders Are More Aggressive Towards Older, More Dangerous Floaters, Walter H. Piper, Katherine R. Lee, Brian Hoover
Territory Holders Are More Aggressive Towards Older, More Dangerous Floaters, Walter H. Piper, Katherine R. Lee, Brian Hoover
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Animals that show aggression often risk injury and incur steep energetic costs. Thus, aggression should occur at such times and towards such opponents as to maximize fitness. We tested hypotheses predicting adaptive territorial aggression in the common loon, a species in which ease of observation of territory owners and floaters (prebreeders) seeking to evict them provide a rare window onto owner-floater competition. As predicted, older, more competitive floaters (4-year-olds and upwards) tended to intrude into territories that had produced chicks the previous year (and, hence, were of high quality). Older floaters also showed predicted increases in aggression and territorial yodeling, …
Investment In Territorial Defence Relates To Recent Reproductive Success In Common Loons (Gavia Immer), Jeremy A. Spool, Lauren V. Riters, Walter H. Piper
Investment In Territorial Defence Relates To Recent Reproductive Success In Common Loons (Gavia Immer), Jeremy A. Spool, Lauren V. Riters, Walter H. Piper
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
As the value of a limited resource such as a territory increases, animals should invest more in the defence of that resource. Because reproductive success often depends on the quality of a breeding territory, reproductive success or failure may alter the perceived value of territory and affect an animal's investment in territorial defence. We used common loons (Gavia immer) to test the hypothesis that animals with recent breeding success would show stronger territorial defence than those with no recent breeding success. Surprisingly, successful loons responded less, not more, to a simulated intrusion. However, birds with success in the …