FIGURE 2 Effect of interannual differences in the date of 50%
snow cover (left column) and accumulated thaw-degree days on 10 June
(right column) on the arrival date (a and b ), pre-lay
interval (c and d ), and mean date of nest initiation
(e and f ) of black brant, snow geese, semipalmated
sandpipers, and Lapland longspurs at a site on the Colville River,
Alaska, 2011–2018. Circles represent year-specific values (±SE for nest
initiation), and solid lines represent the best-fit least-squares
regression ±95% prediction interval (dashed lines). Species-specific
colored triangles to right of figures represent slope parameters that
significantly differ from zero. See Table 4 for estimates (±95%
confidence interval) of slope parameters