In mid-October 1804, Meriwether Lewis wrote this singularly appalling entry in his journal:
This day took a small bird alive of the order of the [blank] or goat suckers. it appeared to be passing into the dormant state. on the morning of the 18th the murcury was at 30 above 0. the bird could scarcely move.— I run my penknife into it’s body under the wing and completely distroyed it’s lungs and heart— yet it lived upwards of two hours this fanominon I could not account for unless it proceeded from the want of circulation of the blood.
If you’re an animal lover like me, you have a hard time with this passage. It’s hard to think of anyone deliberately killing a live animal. But Lewis may be forgiven for his curiosity, for he had just encountered one of the rarest behaviors in the avian world. The bird he found huddled on the ground near the mouth of the Cannonball River in North Dakota was the common poorwill, the only hibernating bird in the world.
Birds that live in seasonally cold climates have to be able to adapt to a variety of weather conditions. To cope with a sudden drop in temperature, many birds are able to put themselves in a state of torpor for several hours. Hummingbirds, for example, can lower their body temperatures, slow their metabolism, and go more or less dormant to save energy during chilly winter nights. But the bird Lewis called a “goatsucker”—at that time unknown to science—is the only bird that can hibernate for long periods of time, going without food and lowering its body temperature almost to that of its surroundings for days or even weeks on end.
Despite his extensive scientific training, Lewis evidently mistook the goatsucker for an eastern whippoorwill, another member of the nightjar family, which it closely resembles. He didn’t realize that he had found an entirely new species. Too bad he was too far north to meet any Hopi Indians, who could have told them their name for the bird was Hölchoko, “’the sleeping one.”
The unique abilities and distinct identity of the common poorwill were finally recognized a few years later by Thomas Nuttall, a botanist who accompanied several fur trading expeditions up the Missouri a few years after Lewis and Clark. The great naturalist’s description of this bird earned him the honor of recognition in its scientific name, Phalaenoptilus nuttallii.
Tomorrow—a special Lewis & Clark salute to the bird, in honor of Turkey Day!