Winter Diets, Gut Lengths, and Interspecific Competition in Alaskan Ptarmigan
Moss R. 1974. Winter Diets, Gut Lengths, and Interspecific Competition in Alaskan Ptarmigan. The Auk. 91(4):737-746
The three species of ptarmigan in interior Alaska winter in the same areas but have different diets. These diets have different physical and chemical characteristics and are also associated with gross differences in the birds' digestive tracts: Willow Ptarmigan have the shortest small intestines and Rock Ptarmigan the smallest gizzards. These differences in gut morphology are claimed to be among the proximate reasons why each species maintains its separate diet. In Alaska, Rock Ptarmigan prefer birch to willow in winter. In Iceland, only Rock Prarmigan occur and there they prefer willow to birch. This reversal is attributed to competition with Willow Ptarmigan in Alaska, causing Rock Ptarmigan to adapt to birch.
- Type
- Journal Article
- Authors
- Moss, Robert
- Units
- CAKN , DENA , WRST , YUCH
- Keywords
- Behavior, Birds, Diet, Foraging, Grouse, Ptarmigan, Rock Ptarmigan, Subarctic, Willow Ptarmigan, Wintering