Not all resources are created equal. In addition to the possession of limited resources, the quality of a resource, or the experiences animals have with a resource, can affect social behavior. In collaboration with Dr. Walter Piper of the Loon Project, I had the opportunity to ask whether previous breeding success altered how Common loons defended their lake territories from intruders (in this species, intrusions range from harmless to deadly). I predicted that loons with previous breeding success would defend their territory with more persistence than loons without previous breeding success.
Using simulated territorial intrusions, I found that loons with previous success actually showed less territorial behavior in the weeks before breeding, but increased territorial behavior just before they were set to lay the first egg of the season. Unsuccessful loons, by contrast, responded with more territorial behavior regardless of the time of season. Because successful birds have to contend with more intruders, it’s possible that they develop a strategy to produce costly defensive behaviors only when absolutely necessary. Our findings were just accepted for publication in the Journal of Avian Biology. Walter has also written more eloquently about our findings on the loon project blog (the blog, by the way, is definitely worth following!).