Willow ptarmigan by the fact that it is not generally found above the tree line while the rock ptarmigan prefers more elevated, barren habitat. The summer plumage is browner and in the winter, the male willow ptarmigan lacks the rock ptarmigan's black stripe between the eyes and bill. The white-tailed ptarmigan ("Lagopus leucura") in North America is smaller, has a white tail and finely-barred greyer plumage and lives permanently above the tree line. The distinctive British Isles subspecies "L. l. scoticus" (red grouse) was once considered a separate true British species but is now classified as a sub-species. This moorland bird is
White-tailed ptarmigan to hatch. Males remain in the vicinity of the nest until the eggs hatch, a period of about 23 days. The precocial young leave the nest six to twelve hours after hatching. They are at first covered with down but become fully fledged in seven to ten days. Ptarmigan chicks begin their lives eating insects. Once the chicks' digestive tracts and ceca are more fully developed, their diets shift to one of flowers and leaves. Hens choose foraging patches where plant species containing proteins are abundant. The hens call their chicks to these plants, which are critical for the growth