Rissa tridactyla (A) Sabine's gull, Xema sabini Bonaparte's gull, Chroicocephalus philadelphia Black-headed gull, Chroicocephalus ridibundus (A) Little gull, Hydrocoloeus minutus (A) Ross's gull, Rhodostethia rosea (A) Laughing gull, Leucophaeus atricilla (A) Franklin's gull, Leucophaeus pipixcan Heermann's gull, Larus heermanni (A) Short-billed gull, Larus brachyrhynchus (A) Ring-billed gull, Larus delawarensis California gull, Larus californicus Herring gull, Larus argentatus Iceland gull, Larus glaucoides (A) Lesser black-backed gull, Larus fuscus (A) Glaucous-winged gull, Larus glaucescens (A) Glaucous gull, Larus hyperboreus (A) Great black-backed gull, Larus marinus (A) Least tern, Sternula antillarum (A) Caspian tern, Hydroprogne caspia Black tern, Chlidonias niger Common tern, Sterna hirundo Arctic tern, Sterna paradisaea (A) Forster's tern, Sterna forsteri Loons Order: GaviiformesFamily: Gaviidae Loons are aquatic birds the size of a large duck, to which they are unrelated. Their plumage is largely gray or black, and they have spear-shaped bills. Loons swim well and fly adequately, but are almost hopeless on land, because their legs are placed towards the rear of the body. Four species have been recorded in Wyoming. Red-throated loon, Gavia stellata Pacific loon, Gavia pacifica Common loon, Gavia immer Yellow-billed loon, Gavia adamsii (A) Shearwaters and petrels Order: ProcellariiformesFamily: Procellariidae The procellariids are the main group of medium-sized "true petrels", characterized by united nostrils with medium septum and a long outer functional primary. Streaked shearwater, Calonectris leucomelas (A) Storks Order: CiconiiformesFamily: Ciconiidae Storks are large, heavy, long-legged, long-necked wading birds with long stout bills and wide wingspans. They lack the powder down that other wading birds such as herons, spoonbills, and ibises use to clean off fish slime. Storks lack a pharynx and are mute. One species has been recorded in Wyoming. Wood stork, Mycteria americana (A) Frigatebirds Order: SuliformesFamily: Fregatidae Frigatebirds are large seabirds usually found over tropical oceans. They are large, black, or black-and-white, with long wings and deeply forked tails. The males have colored inflatable throat pouches. They do not swim or walk and cannot take off from a flat surface. Having the largest wingspan-to-body-weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week. One species has been recorded in Wyoming. Lesser frigatebird, Fregata ariel (A) Cormorants and shags Order: SuliformesFamily: Phalacrocoracidae Cormorants are medium-to-large aquatic birds, usually with mainly dark plumage and areas of colored skin on the face. The bill is long, thin, and sharply hooked. Their feet are four-toed and webbed. One