The Common loon is a highly visible water bird inhabiting many of the lakes within Kejimkujik and the greater park ecosystem. It is a top predator in freshwater ecosystems in the area and is sensitive to a variety of stressors, including mercury bio-accumulation, acidification, water level fluctuation and human disturbance. The monitoring program tracks loon population status, by recording the number of adult pairs and number of chicks on focal lakes at Kejimkujik. Monitoring occurs twice annually in June and August using field observations from volunteers and park staff.