Changes in breeding bird richness and abundance in Montreal parks over a period of 15 years

We compared the breeding bird population and vegetation structure of 201 randomly selected 1 ha plots in 49 urban parks in Montreal, 15 years apart (in 1979–1981 and 1994). The constancy of 17 bird species increased significantly, while that of four others decreased. Increased large-tree cover and a reduction in shrub cover do not explain more than a small proportion of this variation in species constancy. We contend that the installation of bird feeder stations in and around parks goes a long way toward explaining these changes, although the recent arrival in Quebec of the House Finch (Carpodacus mexicanus) and the Northern Cardinal (Cardinalis cardinalis) has definitely played a major role in the changes of the bird assemblage.