Annual Variation in Movement of Sub-Alpine Hatched Willow Ptarmigan Lagopus l. lagopus Broods in Central Norway

The post hatching movements of Willow Ptarmigan broods hatched within the sub-alpine region were studied in 1979-83. Parents with their broods always left the breeding territory in the first week after hatching, indicating that securing a feeding area for the chicks is not the main function of the territory in this species. Brood movements differed in altitudinal range between years; in phenologically early years most broods moved uphill, in late years they remained at lower elevations. This is interpreted as a selection by the ptarmigan of areas of highest nutritive value of the food plants.