Originally a bird of the western mountains, nesting on cliff faces and under rock ledges often in large colonies, the Cliff Swallow expanded its range eastward with the proliferation of bridges and buildings, which provided alternative nest sites. Breeding Bird Survey (BBS) data from Canada suggest a long-term decrease in population since about 1970. However, BBS results are imprecise so this assessment is considered to be of medium reliability. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.
The Cliff Swallow is one of several species of aerial-foraging insectivores showing widespread declines in Canada. In the 1980s, there was a negative change point in the Breeding Bird Survey population trends of swallows, swifts, and nightjars across most of North America (Smith et al. 2015). Causes of these declines remain unclear, but changes in aerial insect populations resulting from land use change, insecticides, and climate change have been suggested as a possible causal factor (Blancher et al. 2009, Nebel et al. 2010, Hallmann et al. 2014, Hallmann et al. 2017, Lister and Garcia 2018). However, a recent study in the Maritimes suggests that the breeding success of Cliff Swallow was not related to insect abundance (Imlay et al. 2017). It should be noted though that other factors, such as parental compensation or the fact that fewer individuals require fewer prey items to survive, may be obscuring any effect on nesting survival. Further broad-scale research on the subject is required. One issue particular to the Cliff Swallow is the apparent reduction in nesting success that occurs when Cliff Swallow colonies are shared with House Sparrows - a consequence of the sparrows' tendency to defend large areas around their nest (Leasure et al. 2010).
Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:
Select any of the sub-regions below to view the BCR strategy for additional details.
