The chief focus of our study is on territorial behavior. We break down our interests into two main themes: 1) how a loon first learns about and acquires a territory, and 2) how, once settled, a loon defends its territory from other loons that wish to usurp it. In the course of answering these two broad questions, we have learned a good deal about familiarity between a loon and its breeding space, nesting habits, interactions between breeding loons and intruders that visit their territories, and the complex communication system used by male breeders via the territorial yodel call.