Lemming. 2014 was a "lemming year", and they swarm over the mountains. The following 2-4 years you hardly see any at all, and then the population explodes again. Cadavers are everywhere, and birds of pray and foxes have a great time. With an increase in predators, the ptarmigan population goes down – they nest on the ground, and eggs and chicks are vulnerable.
The Norway lemming (also Norwegian lemming), Lemmus lemmus, is a common species of lemming found in northern Fennoscandia. It is the only vertebrate species endemic to the region. The Norway lemming dwells in tundra and fells, and prefers to live near water. Adults feed primarily on sedges, grasses and moss. They are active at both day and night, alternating naps with periods of activity.