The most reliable source of data for the Common Nighthawk in Canada is the Breeding Bird Survey (BBS), even though a substantial portion of the species' Canadian breeding population occurs in the boreal forest where there are few BBS routes. Though the BBS is not ideally suited for monitoring crepuscular species, there are sufficient data to calculate precise, long-term trends for the areas covered by the survey. BBS results demonstrate a large decrease, such that the Canadian population has been reduced by 68% since the early 1970s, although numbers appear to be stabilizing over the most recent years. Varying degrees of decrease are evident in all Bird Conservation Regions where the species occurs and for which there are adequately reliable trends (displayed below). BBS results from throughout North America indicate that the continental population has also shown a large decrease over the same time period. Recent and on-going targeted surveys that use protocols designed to better detect this and other nightjar species continue to gather data that will be used to improve trend and population size estimates in the future (e.g., WildResearch). The national population goal is based on the BBS; the Common Nighthawk is considered to have been below acceptable levels of that goal since the early 1980s (see Canada graph below). This goal is consistent with the Common Nighthawk Recovery Strategy's short-term objective to halt the decline, and long-term population objective to ensure a positive population trend (Environment Canada 2016c).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
