In Alaska, the main dietary item of the adults at all times of year is willows such as the Alaska willow Salix alaxensis, with leaves being eaten in summer and buds, twigs and catkins supplying the birds' main nutritional needs in winter and early spring.
Salix | Salix viminalis | Salix caprea | Salix cinerea | Salix arctica | Salix purpurea | Salix atrocinerea | Salix acutifolia | Salix alba | Salix alaxensis | Salix, Pennsylvania | Salix matsudana | ''Salix fragilis'' in native riparian zone | Salix babylonica |
Species from the Alaskan coastline and islands have also adapted well in the Faroe Islands, especially Pinus contorta, Picea sitchensis, Salix alaxensis, Populus trichocarpa and Alnus sinuata.