Figure 1.
Spatial distribution of foraging auks during the breeding season at Kitsissut Avalliit, Greenland.
Razorbills (n = 7) shown in blue, common guillemots (n = 5) in red and Brünnich’s guillemots (n = 6) in black. 50 and 95% kernel contours are represented by solid and dashed lines, respectively. The breeding colony is marked with a yellow star and differences in depth between isobaths are 100 m.
Figure 2.
Spatial distribution of auks during September and April.
50% (solid) and 95% (dashed) kernel distribution of razorbills (n = 9, blue), common guillemots (n = 8, red) and Brünnich’s guillemots (n = 6, black) during the first half of September (left panel) and April (right panel). Razorbills left the east coast of North America at the end of April, thus the activity area north of 50° N represents the period from 24th of April and onwards. The breeding colony is marked with a yellow star.
Figure 3.
Median maximum dive depth of auks on an annual cycle.
Median maximum dive depth of Brünnich’s guillemot (BC), common guillemots (CG) and razorbills (RB) during the breeding season (A), post-breeding period (September, B) and pre-breeding period (April, C). The bottom and top of the box show the 25th and 75th percentiles, respectively around the median (solid line). The vertical dashed lines (whiskers) show either the maximum value or 1.5 times the difference in the response variable between its first and third quartiles, which ever is the smallest. Outliers are shown with circles. When there are no outliers the whiskers show the maximum and minimum values.
Figure 4.
Stable isotope values of auks on an annual cycle.
δ13C and δ15N values (mean ± SE) of blood (breeding), back-feathers (post-breeding) and throat feathers (pre-breeding), of adult razorbills (blue), common guillemots (red) and Brünnich’s guillemots (black).