Who definitively described hibernation-like torpor in the common poorwill in 1948?

Edmund Jaeger definitively described hibernation-like torpor in the common poorwill in 1948. His work established that this North American nightjar could remain inactive for unusually long periods, with a greatly reduced body temperature.

Jaeger’s account followed his 1946 discovery of a torpid poorwill in California’s Chuckwalla Mountains. The bird was concealed among rocks during winter, and the observation helped turn scattered reports into a documented biological phenomenon. The behavior is generally called extended torpor or hibernation-like torpor because birds do not fit the classic mammalian definition of hibernation as neatly.

The common poorwill remains famous for the duration of this state: it may stay inactive for weeks or even months. An earlier clue came from Meriwether Lewis, who recorded apparently hibernating poorwills during the Lewis and Clark Expedition in 1804, but the significance was not understood at the time. Jaeger’s 1948 description made the phenomenon scientifically prominent.