Vegetated zones of highway rights-of-way (ROW) are unique ecotones that can increase habitat heterogeneity at the landscape level and play a role in the maintenance of plant and animal conservation on a regional scale in certain human-dominated landscapes. To determine if they are unique habitats differing from the surrounding environment, we compared the abundance, richness, and species composition of bird communities using ROW in the St. Lawrence Valley lowlands of southern Quebec (Canada) in relation to the habitats in the adjacent land-use area, in 3 landscapes (suburban, intensive agriculture, and agroforestry) during 3 different seasons (spring, summer, and fall) corresponding to birds' spring migration, breeding, and fall migration periods. We recorded a total of 8368 birds belonging to 74 species. The avian community at the intensive agricultural site differed from those of the other 2 sites, in both species' composition and abundance. Bird use of ROW also varied as a function of the season: there was a higher species richness in spring, but a higher species abundance in fall. Species abundance and richness were higher in the adjacent areas than in the ROW during all 3 seasons. Species richness was inversely related to the presence of field crops in the adjacent areas. We conclude that highway ROW in southern Quebec are not unique habitats that differ from the surrounding landscape but rather supplemental habitats that help maintain bird populations at the regional scale, particularly in landscapes dominated by intensive agriculture where remnant patches of natural habitat are becoming less common.