The summer diets of a natural population of white-tailed ptarmigan (Lagopus leucurus), an herbivorous alpine grouse, in the Rocky Mountains and an introduced population in the Sierra Nevada were compared to determine if differences in alpine tundra plant communities affected nutritional intake. Foraging selections of 28 adult ptarmigan were recorded regarding number, amount, availability, nutritional, mineral and energy content of plant species eaten. The average diet of the Rocky Mountain ptarmigan was composed of nine plant species (99% g dry wt), while the average diet of the Sierra Nevada ptarmigan was composed of only two plant species, Salix anglorum and Carex jonesii (99% g dry wt). Although plant species eaten differed between the populations, the energy and lipid content of the diets were nearly identical. The diet of Sierra Nevada ptarmigan was 28% higher in protein and 13% lower in carbohydrate than the diet of Rocky Mountain ptarmigan, likely due to high consumption of Salix leaves and low consumption of flowers by the Sierra Nevada ptarmigan. Both populations exhibited sampling behavior (ingesting occasional bites from many species), which would allow ptarmigan to track changing resources in the highly variable alpine environment and may have enabled the introduced ptarmigan to identify a suitable diet.
|Number of pages||6|
|Journal||Arctic, Antarctic, and Alpine Research|
|Publication status||Published - May 2005|