Cormorant

Phalacrocoracidae is a family of some 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed. There is no consistent distinction between "cormorants" and "shags", and these appellations have been assigned to different species randomly.

Cormorants and shags are medium-to-large birds, with body weight in the range of 0.35–5 kilograms (0.77–11.02 lb) and wing span of 45–100 centimetres (18–39 in). The majority of species have dark feathers. The bill is long, thin and hooked. Their feet have webbing between all four toes. All species are fish-eaters, catching the prey by diving from the surface. They are excellent divers, and under water they propel themselves with their feet with help from their wings; some cormorant species have been found to dive as deep as 45 metres. They have relatively short wings due to their need for economical movement underwater, and consequently have the highest flight costs of any bird.

Shag

Shag, Shags, Shagged or Shagging may refer to:

Music

Bird

Birds (class Aves) are a group of endothermic vertebrates, characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.

The fossil record indicates that birds are the last surviving dinosaurs, having evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago, and the last common ancestor is estimated to have lived about 95 million years ago. DNA-based evidence finds that birds radiated extensively around the time of the Cretaceous–Paleogene extinction event that killed off the non-avian dinosaurs. Birds in South America survived this event and then migrated to other parts of the world via multiple land bridges while diversifying during periods of global cooling. Primitive bird-like "stem-birds" that lie outside class Aves proper, in the group Avialae, have been found dating back to the mid-Jurassic period. Many of these early stem-birds, such as Archaeopteryx, were not yet capable of fully powered flight, and many retained primitive characteristics like toothy jaws in place of beaks and long bony tails.