Do birds fly at night?
Most birds can fly at night, but will only do so if necessary. The reason for this is that their eyes, like human eyes, are not designed to see in nighttime conditions. If a bird cannot see well, it risks injury by flying at night. Unless startled into flight by a predator, most birds will avoid leaving their nighttime roost. Other species, such as owls and nightjars (nighthawks and whippoor-wills) fly primarily at night, their most active time, and sleep during the day. Songbirds, such as warblers and tanagers, which are active during daylight hours, do fly at night during migration, when they must travel long distances. It is thought that these migrants fly at night because the air is cooler, so there is less chance of their overheating during the long, strenuous periods of flight.
