The Canadian population of Blackpoll Warbler is best monitored by the Breeding Bird Survey (BBS). It is well-suited to detecting the species and has high precision, but its overall coverage of the population is low because most of the breeding range is farther north than the majority of survey routes. This means the national trend most represents the southern portion of the population, and the observed decline may at least partly reflect a northward shift in the summer range. The BBS shows a steady decline beginning in the early 1980s, with a total loss of 81%. In the regions with medium to high geographic coverage and precision in estimates (central and southern British Columbia, central Ontario and Quebec, and the Maritimes) declines since 1970 range from 66% to 98%. This species is also detected in large numbers by the Canadian Migration Monitoring Network, but long-term trends are highly variable among stations, suggesting some changes in migratory routes over time but not providing a clear signal about changes in overall population size.

The goal for Blackpoll Warbler is to increase the population to the level it was at in the early 1970s, based on the Breeding Bird Survey. Blackpoll Warbler is currently below its goal range and continuing to decline. 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 25% of the goal by 2050. Achieving this target, and ultimately reaching the national goal for this species, will require deliberate conservation action.