Six species of terns have been recorded in Galapagos: 2 residents and 4 vagrants. Terns are similar to gulls in many respects but are generally smaller, with narrower wings; thinner, straighter bills which lack the marked gonydeal angle; and shorter legs. Whilst terns are usually predominantly gray and white, the two species that breed in Galápagos are wholly dark brown (Common Noddy) and black and white (Sooty Tern). The sexes are alike. Terns feed by picking food from the surface of the water or by plunge-diving.