The Canadian population of Swainson's Hawk is best monitored by the Breeding Bird Survey (BBS), which samples most of the Canadian breeding range and has high precision in trend estimates. The national trend showed a strong increase from the early 1970s to late 1980s, followed by a rapid decline over the following decade, attributed to consumption of poisoned insect prey on the Argentinean wintering grounds. Following a ban on the use of the insecticide monocrotophos, the population began to rebound again, and has recently returned to near the peak levels observed in the late 1980s, 51% above the early 1970s. At the northern limits of its breeding range in Northwest Territories and northern Alberta, the population has not rebounded, and remains slightly below 1970s levels.

The goal for Swainson's Hawk is to remain at or above its recent population level, based on the Breeding Bird Survey. Trend data show that Swainson's Hawk is currently within its goal range.