The number of common loons and their breeding range have decreased significantly since the beginning of the century. There is concern about the number of breeding pairs and the number of fledglings. In order to determine what the population status is throughout La Mauricie National Park, loons are monitored through two aerial surveys carried out over all the lakes in the park of more than three hectares as well as by canoe on the most accessible lakes in order to confirm the presence of loons and locate their nests.