The piles of hay are often partially exposed to sunlight, allowing successive layers of hay to cure. Pikas use the same sites for their haystacks year after year. Little is known about what pikas do in the winter, although they are sometimes seen sunning themselves on large rocks on clear days. Presumably, they divide the rest of their time between feeding, chasing off other pikas trying to raid their haystacks, and resting up for the next haying season. When one colony member gives an alarm call, others immediately dive into their burrows or escape into tiny spaces between the rocks.
Weasels are among the pika s most persistent predators.
The weasel s small size allows it to pursue pikas into burrows and among the rocks. A relative of the weasel, the marten, also hunts pikas on occasion. Other predators include hawks, eagles, and owls. Pikas respond differently to different predators. When a hawk, marten, or other large predator appears, pikas call loudly to warn others and then disappear into the rocks.