Overall, the population of Vesper Sparrow in Canada is well monitored by the Breeding Bird Survey (BBS). It is well-suited to detecting the species, covers most of the range, and has high precision. The national trend shows a steep decline from the early 1970s to early 1980s, followed by a long period of fluctuations around an overall slower decline, amounting to a cumulative loss of 54% since 1970. There is some regional variability, with little change in the southern Prairies but losses of over 80% in the northern Prairies, central and southern Ontario and Quebec, and the Maritimes. 

No monitoring data are available specific to the Canadian population of P. g. affinis, but there is nonetheless high confidence that it has undergone a large decrease since 1970 given that it formerly occurred on both Vancouver Island and the lower Fraser Valley, but was last confirmed breeding at one location on Vancouver Island in 2014.

The national goal for Vesper Sparrow is to increase the population to the level it was at in the early 1970s, based on the Breeding Bird Survey. Trend data show that Vesper Sparrow 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 90% of the goal by 2050. Achieving this target, and ultimately reaching the national goal for this species, will require deliberate conservation action.

The affinis subspecies has a Recovery Strategy under the Species at Risk Act, which set a goal of at least 30 breeding pairs (60 individuals, ECCC, 2016). Although targeted monitoring of this population is currently lacking, it is almost certainly below its goal range.