Mexican Whip Poor-Will
(Antrostomus arizonae)

Found across Mexico and parts of Central America, the Mexican Whip-poor-will is a nocturnal bird perfectly camouflaged to resemble leaf litter and bark — and is almost never seen despite being heard regularly. 

Like other nightjars, it is capable of entering a state of torpor during cold periods — dramatically slowing its metabolism and essentially hibernating for short periods, which is unusual for a bird!