Population trends of Canada Warbler are best monitored by the Breeding Bird Survey (BBS). The BBS is well-suited to detecting the species and has high precision, though coverage of the northern parts of the range is limited so the reliability of the BBS is considered medium. The national BBS trend shows a decline from the 1970s until around 2005, followed by stabilization and a slight rebound in recent years. The national population remains 63% below its level from the 1970s. Though this pattern is fairly consistent across much of the Canadian range, the greatest loss has occurred in the Maritimes where abundance has fallen by 90% and continues to decline.

The goal for Canada Warbler is to increase the population to the level it was at in the early 1970s, based on the Breeding Bird Survey. Canada Warbler is currently below its goal range, but has shown an increase over the past decade. Analysis considering the historical population loss and recent trend suggests that it is unlikely that the goal can be met by 2050, so the interim target is to reach 80% of the goal by 2050. Achieving this target, and ultimately reaching the national goal for this species, will require deliberate conservation action. 

This is largely consistent with the Recovery Strategy for Canada Warbler under the Species at Risk Act, which has a short-term population objective of halting the national decline by 2025, while ensuring that the population does not decrease more than 10% between 2015 and 2025 (ECCC, 2016). Beyond 2025, it stipulates a long-term objective of a positive 10-year trend. Breeding Bird Survey data indicate that the short-term objective has been met, and the population is on track for also achieving its next milestone.