In recent years, we have made important findings along four major axes: 1) changes in behavior and survival with age, especially senescence, 2) habitat preferences, especially the preference of loons hatched on small lakes to settle on small lakes, which contain less food and produce fewer chicks than large lakes, 3) changes in yodel frequency of males that signal their size and body condition, 4) differences in tameness (tendency to dive at a certain distance when approached by canoe) among individuals.
At present, we are exploring the impact of age on reproductive and aggressive behavior of loons and have recently described a striking system of terminal investment in males. In 2017, we began to explore possible proximate causes (hormones, parasites, telomeres) of loss in condition with age.
Having established that natal habitat preference is very strong in this species, we have begun to look at the possibility that small lakes are ecological traps and also to investigate the opposite possibility — that there are benefits for adults breeding on small lakes that might offset the obvious disadvantages.
An unexplored avenue for research on our project is the vocal behavior of males and how it relates to male senescence. Males signal identity, size, and body condition with their territorial yodel and increase their rate of yodelling as they age. It seems virtually certain that yodels change in specific ways with age and that flying intruders respond differently to yodels from young and old territory owners. Several exciting playback experiments are possible in the loon system.
Some of our adults allow approach to within a few meters without alarm, while others begin to dive and avoid us at 50 meters. We have just begun to measure such tameness with laser rangefinders and have learned already that tameness is consistent within individuals, highly correlated between pair members, and probably heritable. We are currently trying to determine whether tameness of loons matches the degree of human recreational activity on their breeding lake and see if tameness provides a fitness benefit.
We welcome inquiries from potential collaborators with interest and expertise that match one or more of these goals. Chapman University supports postdoctoral fellowships each year through the Grand Challenges Initiative, which provides training in instruction as well as collaborative research opportunities with faculty.