Goat-sucker, or Fern-owl, in ornithology, a genus of birds belonging to the order of passerines. The beak is incurvated, small, tapering, and depressed at the base; the hairs at the mouth, which it opens very wide, are placed in a row. There are two species, viz. the Europaeus, with the tubes of the nostrils hardly visible. It is a native of Europe, and feeds upon moths and nocturnal insects. This bird is said to suck goats in the night. See Pl. 63. 2. The Americanus, has the tubes of the nostrils very conspicuous. This is a night-bird, and is found in America.