Establishment of a breeding population of Canada Geese in southern Quebec

Abstract

We documented the natural establishment of a breeding population of Canada Geese (Branta canadensis) on four islands located in the St. Lawrence River near Montreal. Number of nests increased from 3 in 1992 to 50 in 2000. We estimated that the population is currently growing at 36-46% per year. Over the years, nest success was high with 80% of the nests hatching at least one egg giving a Mayfield estimate of 66%. Morphometric measurements of geese nesting and molting in southern Quebec conform to those of Giant Canada Geese (B. c. maxima). Resightings of banded and neck-collared geese revealed that two birds marked in New York and one in Michigan, as part of resident flocks, have colonized the islands. Moreover, natal-fidelity of a female hatched on one of the islands indicates that the breeding population will continue growing. The colonization of the islands may result from the expansion of the resident populations of southern Ontario and eastern United States or from escapes from captive flocks. We also hypothesize that the establishment could be related to the use of the area by molt migrant resident geese that may return the following spring to breed. We recommend that management actions be taken to prevent establishment of a larger population of summer resident geese in southern Quebec. Otherwise, we predict that problems like those caused by resident Canada Geese established in urban and suburban settings elsewhere will occur. Climatic changes in a near future may also incite some Canada Geese to winter in southern Quebec and this could exacerbate potential problems.