The common poorwill spends much of winter inactive while concealed in what?

The common poorwill spends much of winter inactive while concealed in piles of rocks.

The common poorwill is exceptional among birds because it can enter torpor for an extended period, sometimes lasting weeks or months. This behavior has been documented mainly along the southern edge of its range in the United States, including parts of California and New Mexico, where the bird shelters in rocky places during winter.

The poorwill’s inactivity resembles hibernation, although birds are more commonly associated with daily torpor than with a winter-long dormant period. Concealment among rocks helps protect the bird while it reduces activity, body temperature, and energy use. The bird normally feeds at night on insects such as moths, beetles, and grasshoppers.

Naturalist Edmund Jaeger described the behavior definitively after finding a hibernating poorwill in California’s Chuckwalla Mountains in 1946. Meriwether Lewis had recorded hibernating poorwills during the Lewis and Clark Expedition in 1804, but the observation was not fully understood. The Hopi name for the bird, hölchko, reportedly means “The Sleeping One.”