The majority of these species eat small invertebrates picked out of the mud or soil. Variation in length of legs and bills enables multiple species to feed in the same habitat, particularly on the coast, without direct competition for food. There are 22 species which have been recorded in Equatorial Guinea. Order: CharadriiformesFamily: Stercorariidae  The family Stercorariidae are, in general, medium to large birds, typically with grey or brown plumage, often with white markings on the wings. They nest on the ground in temperate and arctic regions and are long-distance migrants. There are 7 species worldwide and 1 species which occurs in Equatorial Guinea. Order: CharadriiformesFamily: Laridae  Laridae is a family of medium to large seabirds, the gulls, terns, and skimmers. They are typically grey or white, often with black markings on the head or wings. They have stout, longish bills and webbed feet. Terns are a group of generally medium to large seabirds typically with grey or white plumage, often with black markings on the head. Most terns hunt fish by diving but some pick insects off the surface of fresh water. Terns are generally long-lived birds, with several species known to live in excess of 30 years. Skimmers are a small family of tropical tern-like birds. They have an elongated lower mandible which they use to feed by flying low over the water surface and skimming the water for small fish. Order: PterocliformesFamily: Pteroclidae  Sandgrouse have small, pigeon like heads and necks, but sturdy compact bodies. They have long pointed wings and sometimes tails and a fast direct flight. Flocks fly to watering holes at dawn and dusk. Their legs are feathered down to the toes. There are 16 species worldwide and 2 species which occur in Equatorial Guinea. Order: ColumbiformesFamily: Columbidae  Pigeons and doves are stout-bodied birds with short necks and short slender bills with a fleshy cere. Order: PsittaciformesFamily: Psittaculidae   Order: PsittaciformesFamily: Psittacidae   Order: CuculiformesFamily: Musophagidae  The turacos, plantain eaters and go-away-birds make up the bird family Musophagidae. They are medium-sized arboreal birds.