Why are loons chasing each other across my lake?

Your encounter sounds like a territorial flight—a dispute between two loons. Late June is well past the point when loons are first establishing territories, but it’s possible one loon had been displaced from its own lake or had not managed to find a territory yet and so was intruding on another bird’s territory. Loons can battle for a long time, and sometimes one is actually killed. It must have been both thrilling and disconcerting to witness this.

Read more about Common Loons in our online species guide, and listen to their ethereal calls in this audio slideshow.