Willow ptarmigan a range of lower plant species. It is also believed that the greening of parts of the Arctic is affecting Willow Ptarmigan populations by altering the shape and size of the shrubs they are able to feed on. Male willow ptarmigans are territorial birds. Males arrive in the breeding areas and set up territories in April and May, aggressively defending them against male interlopers. When the females arrive a few weeks later, the male performs courtship displays such as aerial manoeuvres, strutting and tail-fanning. When she has chosen a mate and a nesting site, the female lays a clutch of
Climate of the Arctic of heat from the subsurface land and ocean (both of which gain heat in summer and release it in winter) to the surface and atmosphere. Arctic days lengthen rapidly in March and April, and the sun rises higher in the sky, both bringing more solar radiation to the Arctic than in winter. During these early months of Northern Hemisphere spring most of the Arctic is still experiencing winter conditions, but with the addition of sunlight. The continued low temperatures, and the persisting white snow cover, mean that this additional energy reaching the Arctic from the sun is slow to have