Any of numerous species (family Procellariidae) of long-winged seabirds named for their habit of gliding on stiff wings along wave troughs. Typical shearwaters are the 12–17 drab, slender-billed species of Puffinus, 14–26 in. (35–65 cm) long. Shearwaters nest in a burrow on offshore islands and coastal hills in the Atlantic and Mediterranean and throughout most of the Pacific. A colony may consist of hundreds of thousands of pairs; at night, when the calling adults move in and out of the burrows, the din is deafening. See alsofulmar, petrel.