The Sleeping One
Migration is one way for insectivorous birds to escape the rigors of winter, but one, the Common Poorwill, has another tactic. In the relatively mild climate of the desert Southwest, poorwills tuck themselves away in rock crevices or rotten logs and go into a state of torpor for days to weeks at a time. The bird’s heartbeat slows, and its body temperature may drop by 40 degrees F. This is remarkably similar to the true hibernation of many species of rodents, including the legendary “groundhog” (Woodchuck).
This peculiar behavior (for a bird) was known to native people, including the Hopis who called the bird Hölchoko, “the sleeping one.” The first scientist known to have encountered a “hibernating” Poorwill was explorer Meriwether Lewis. In his journal entry for October 16, 1804, Lewis reported the following:
This day took a small bird alive of the order of the…goat suckers. it appeared to be passing into the dormant state. on the morning of the 18th the murcury was at 30 a[bove] 0. the bird could scarcely move.
Unfortunately, the significance of this encounter was lost in the myriad of other discoveries by the Lewis and Clark expedition.
Almost a century and a half later, another naturalist, Edmund Jaeger, stumbled onto a torpid poorwill in the Chuckwalla Mountains of southern California. Dr. Jaeger published his story of discovery in The Condor, National Geographic, and his book Desert Wildlife, as well as other venues. Following publication of his discovery, Dr. Jaeger received several letters from others who had also found torpid poorwills but not recognized the significance of their discoveries. Even Aldous Huxley, the author of Brave New World whose grandfather and two brothers were prominent biologists, wrote to relate his story of finding a dormant European Nightjar, a close relative of the poorwill, while on vacation in England.
In 1964, the site of Dr. Jaeger’s discovery was protected by The Nature Conservancy. A 160-acre preserve commemorates the canyons where modern science joined native people’s knowledge of this strange avian behavior. Dr. Jaeger died in 1983 at the age of 96, and his friends and students scattered his ashes in the canyon of the poorwills.