Seabird in the context of "Atlantic puffin"

Birds are a group of warm-blooded theropod dinosaurs constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich. There are over 11,000 living species and they are split into 44 orders. More than half are passerine or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. The study of birds is called ornithology.

Birds evolved from earlier theropods, and thus constitute the only known living dinosaurs. Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians. Birds are descendants of the primitive avialans (whose members include Archaeopteryx) which first appeared during the Late Jurassic. According to some estimates, modern birds (Neornithes) evolved in the Late Cretaceous or between the Early and Late Cretaceous (100 Ma) and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non-ornithuran dinosaurs.

The northern gannet (Morus bassanus) is a seabird, the largest species of the gannet family, Sulidae. It is native to the coasts of the Atlantic Ocean, breeding in Western Europe and Northeastern North America. It is the largest seabird in the northern Atlantic. The sexes are similar in appearance. The adult northern gannet has a mainly white streamlined body with a long neck, and long and slender wings. It is 87–100 cm (34+1⁄2–39+1⁄2 in) long with a 170–180 cm (67–71 in) wingspan. The head and nape have a buff tinge that is more prominent in breeding season, and the wings are edged with dark brown-black feathers. The long, pointed bill is blue-grey, contrasting with black, bare skin around the mouth and eyes. Juveniles are mostly grey-brown, becoming increasingly white in the five years it takes them to reach maturity.

Nesting takes place in colonies on both sides of the North Atlantic, the largest of which are at Bass Rock (75,000 pairs as of 2014), St. Kilda (60,000 pairs as of 2013) and Ailsa Craig (33,000 pairs as of 2014) in Scotland, in Ireland (Sceilg Bheag; little Skellig, 35,000 pairs in 2011), Grassholm in Wales, and Bonaventure Island (60,000 pairs in 2009) off the coast of Quebec. Its breeding range has extended northward and eastward, with colonies being established on Russia's Kola Peninsula in 1995 and Bear Island (the southernmost island of Svalbard), in 2011. Colonies are mostly located on offshore islands with cliffs, from which the birds can more easily launch into the air. The northern gannet undertakes seasonal migrations and catches fish (which are the mainstay of its diet) by making high-speed dives into the sea.

A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term water bird is especially applied to birds in freshwater ecosystems, although others make no distinction from seabirds that inhabit marine environments. Some water birds (e.g. wading birds) are more terrestrial while others (e.g. waterfowls) are more aquatic, and their adaptations will vary depending on their environment. These adaptations include webbed feet, beaks, and legs adapted to feed in the water, and the ability to dive from the surface or the air to catch prey in water.

The term aquatic bird is sometimes also used in this context. A related term that has a narrower meaning is waterfowl. Some piscivorous birds of prey, such as ospreys, sea eagles, fish eagles, fish owls, and fishing owls, hunt aquatic prey but do not stay in water for long and live predominantly over dry land, and are not considered water birds. The term waterbird is also used in the context of conservation to refer to any birds that inhabit or depend on bodies of water or wetland areas. Examples of this use include the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) and the Wallnau Waterbird Reserve.

Cory's shearwater (Calonectris borealis) is a large shearwater in the seabird family Procellariidae. It breeds colonially on the archipelago of the Azores in the eastern Atlantic. Outside the breeding season it ranges widely in the Atlantic. It was formerly considered to be conspecific with Scopoli's shearwater.

The yelkouan shearwater, Levantine shearwater or Mediterranean shearwater (Puffinus yelkouan) is a medium-sized shearwater in the seabird family Procellariidae. It was formerly treated as a subspecies of the Manx shearwater (Puffinus puffinus).

Guano (Spanish from Quechua: wanu) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a lesser extent, sought for the production of gunpowder and other explosive materials.

The 19th-century seabird guano trade played a pivotal role in the development of modern input-intensive farming. The demand for guano spurred the human colonisation of remote bird islands in many parts of the world.

Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons (i.e. planktivores) and other small aquatic organisms (e.g. krill). They are in turn preyed upon by various predators including larger fish, seabirds and marine mammals, this making them keystone species in their aquatic ecosystems.

The typical ocean forage fish feed at the lower trophic level of the food chain, often by filter feeding. They include particularly fishes of the order Clupeiformes (herrings, sardines, shad, hilsa, menhaden, anchovies, and sprats), but also other small fish, including halfbeaks, silversides, smelt such as capelin and goldband fusiliers.

A skerry (/ˈskɛri/ SKERR-ee) is a small rocky island, or islet, usually too small for human habitation. It may simply be a rocky reef. A skerry can also be called a low sea stack.

Skerries may have vegetative life such as moss and small, hardy grasses. They are often used as resting places by animals such as seals and birds.