The pachacua nightjar ( Phalaenoptilus nuttallii) is the only species of bird known to go into hibernation caused by reduced food supply and harsh temperatures.
While other birds migrate or go into brief states of lethargy such as the hummingbird -which groups five species mainly in neotropical areas-, the pachacua nightjar can hibernate for several months. During lethargy, your breathing rate is reduced, your body temperature also drops, and your heart rate drops.
Thus, there are species of birds that go into torpor for a brief period of time, but in many it is not considered a true hibernation.
