The Northern Gannet (Morus bassanus) is a seabird and it is the largest member of the gannet family, Sulidae. It has the same colours as the Australasian Gannet and is similar in appearance. Adults are 81-110 cm (32-43 in) long, weigh 2.2-3.6 kg (4.9-7.9 lb) and have a 165-180 cm (65-71 in) wingspan. Each wing measures between 47 and 53 cm when outstretched and the beak measures between 9 and 11 cm (measured from the head). The two sexes are a similar size. The plumage of the adults is white with dark wing tips, with colours that range from brown to black. The colour of the head, cheeks and side of the neck depends on the season and the individual, during breeding, the head and neck are brushed in a delicate yellow. Although this colouring may not be evident in some individuals. The feathers are waterproof, which allows the birds to spend long periods in water. A water impermeable secretion produced by a sebaceous gland covers the feathers and the birds spread it across their body using their beak or their head. The eye is light blue, and it is surrounded by bare, black skin, which gives the birds their characteristic facial expression. Young birds are dark brown Fledglings are brown with white wing tips. They have white spots on their head and on their back and a v-shaped white area underneath. The plumage of year-olds can be almost completely brown, in the second year the birds? appearance changes depending on the different phases of moulting: they can have adult plumage at the front and continue to be brown at the rear. They gradually acquire more white in subsequent seasons until they reach maturity after five years.
Habitat and Distribution
Their breeding range is the North Atlantic on coasts influenced by the Gulf Stream. The exception being the colonies of the Gulf of Saint Lawrence and the islands off the east coast of Canada. They normally nest in large colonies, on cliffs overlooking the ocean or on small rocky islands.
Northern gannets forage for food during the day, generally by diving into the sea. They search for food both near to their nesting sites but also further out to sea. Birds that are feeding young have been recorded searching for food up to 320 km from their nest. It has been found that 2% of birds nesting in the colony on Bass Rock search for fish at Dogger Bank, between 280 and 320 km away. It is likely that they fly greater distances than this while searching for food, possibly up to double this distance, however, they normally fly less than 150 km.
The preferred nesting sites are on coastal hillsides or cliffs If these sites are not available northern gannets will nest in groups on islands or flat surfaces. Nests are made from seaweed, plants, earth and all types of object that float on the sea. The males usually collect the materials. Once males have found a place to breed they try to attract an available female. The females will fly over the colony a number of times before landing. Their posture, with the neck stretched out, tells the male that they are available for courtship. The male will then shake their heads in a similar way to when they are guarding their nest but with their wings closed. Northern gannets only lay one egg that on average weighs 104,5 grams. Incubation takes 42 to 46 days.
Calls and Songs
The northern gannet does not have a very characteristic acoustic repertory. Its typical call is rab-rab-rab, which is emitted when fishing and also when on the nest. They have a special call when they approach the colony, this call is often heard because there is usually a lot of toing and froing in a colony. Males and females make similar calls.