RUI / LTREB -- Long-term Investigation of Territorial Behavior and Population Dynamics in the Common Loon

Chapman University, Orange CA

Investigators

Abstract

This project focuses on 95 territorial pairs of common loons, aquatic birds that breed on lakes across the northern U.S. and Canada. The research examines three chief topics: 1) fatal fighting among males for territories, 2) use of the 'yodel' call to defend territories, and 3) stability of a population that is threatened by shoreline development, recreational activity and the toxic effects of methylmercury. This study requires marking of loons with leg bands, observation from canoes, and simple experiments such as playbacks of territorial calls and placement of loon decoys. This research project addresses scientific questions about animal behavior. One such question is 'Why do long lived species engage in lethal battles for territory when they have access to unused breeding space nearby?'. Because the investigator has a large sample of known-age birds in the study population, it will be possible to test several hypotheses to answer the question, including the hypothesis that fatal battlers are old residents with nothing to lose. Loons are very charismatic birds, and behavioral findings will be disseminated through popular articles, media coverage and educational websites for schoolchildren. An additional aim of the project - measurement of population stability and impacts of methylmercury - will determine whether state and federal agencies should study means to increase loon reproductive success and reduce emissions of mercury from industrial sources. The project extends a fruitful 15 year partnership between a small college and a major research university that trains 5 undergraduates annually in techniques required for field study of animals.