Swifts: Apodidae

Swifts become active at dawn. They are noisy and live in large groups called colonies. Some species migrate, flying from an area with harsh winter weather to a warmer climate where there is a larger food supply.

Swifts are monogamous (muh-NAH-guh-mus), mating with one partner. Birds make nests out of twigs, feathers, and items they find while flying. To hold the material together, swifts use their saliva, the liquid solution in their mouths, which hardens around the nest material.

The female swift lays one to six eggs. Both parents incubate the eggs, sitting on them to keep them warm in order for them to hatch. Eggs hatch in nineteen to twenty-eight days. Both parents feed the young. Other swifts, called cooperative breeders, may assist the parents in feeding. The adults carry insects for the young in pouches located below their tongues.

Cave swiftlets use only saliva when building their nests. People in Asia take the nests of some swiftlets and use them as the main ingredient in bird's nest soup. Since caves are dark, cave swiftlets use echolocation (eck-oh-loh-KAY-shun) to guide them as they move around in the caves. The birds make a sound and listen to the echoes that bounce off the surfaces.