Demographic analysis
Using 1,766 BBS routes from 1968-2021, we estimated the range-wide trend in population size to be -0.29% per year (95% CI: -0.57, -0.02). Trends among the breeding populations were variable (Table 2). The Northern Temperate breeding population was estimated to be increasing by 0.67% per year (95% CI: 0.33, 1.01). The Southern Temperate breeding population was estimated to be declining by 0.34% per year (95% CI: -0.75, 0.06), but the credible intervals were overlapping 0, thus indicating potential stability in that population. The remaining three populations (Basin Rockies, Maritime Provinces, and Western Boreal) were all estimated to be declining and had negative values for the upper bounds of the 95% credible intervals. The Northern Temperate population had the highest relative abundance of 3.70 (95% CI: 3.09, 4.52), followed by Maritime Provinces (1.96; 95% CI: 1.57, 2.49), Western Boreal (0.66; 95% CI: 0.52, 0.84), Southern Temperate (0.15; 95% CI: 0.13, 0.17), and Basin Rockies (0.01; 95% CI: 0.01, 0.02). The density of the number of birds per BBS route was highest in the Maritime Provinces (30.56; 95% CI: 24.33, 38.60), followed by Northern Temperate (15.16; 95% CI: 12.68, 18.54), Western Boreal (1.66; 95% CI: 1.31, 2.10), Southern Temperate (0.67; 95% CI: 0.58, 0.78), and Basin Rockies (0.16; 95% CI: 0.10, 0.25).