Northern Gannet Morus bassanus
- IdentificationVisual tips about this species
- BehaviourHabitat, behaviour, and food
- PopulationSubspecies and numbers
- ReproductionNesting and eggs
Identification
Gannets have a variety of plumages, from the dark speckled brown juveniles to the immaculate, almost white, adults with various brown and white plumages in between. At all ages though Gannets can be told by their unique shape with long bodies, pointed at both ends, and impressively long, pointed wings enabling them to fly quickly, but effortlessly, with long glides.
Ageing
Complicated series of plumages with birds taking 4-6 years before they look like full adults. Juveniles are all dark, superficially resembling large shearwaters, but told apart by their long pointed head and tail. Adult plumage gained gradually, with birds becoming progressively whiter each year.
Voice
Their incessant 'grog-grog' calls can be heard at any of their twenty-two British breeding colonies scattered around our coasts.
Sexing
Sexes similar.
Length
90cm
Behaviour
Catch fish by spectacular plunge-diving. Flying birds close their wings making their whole body streamlined like an arrow which dives head-first into the water. Moments later the bird returns to the surface, often with a large fish struggling in its mouth.
Migration
Many adults are present in northern waters throughout the winter, but most move south after breeding to winter between the Bay of Biscay and the coast of western Africa.
Habitat
Breeds on rocky islands and cliffs. Winters in coastal and off-shore waters.
Food
Almost exclusively fish.
Population trends
The population of this species has recently increased dramatically. Since the turn of the century, Gannets have spread to France (1930's), Norway (1946) and Germany (1991) and numbers have greatly increased in Britain where many new colonies have developed. This increase has been due to increased protection from persecution and an increased food supply (offal from fishing fleets).
Subspecies
Monotypic.
Population in Britain and Ireland
The British population is estimated at 201000 pairs, with 24 500 pairs in Ireland. Together this represents 70% of the world's population.
Where in Britain and Ireland
Probably the most accessible breeding colony on the mainland is at Bempton Cliffs RSPB Reserve in East Yorkshire, where roughly 1 300 pairs nest. However, they can also be seen offshore from almost any coastal site at most times of the year.
Population in Europe
The entire European population is estimated at 230,000 pairs, of which 160,000 breed around the coast of Great Britain (70% of the European population.)
Where in Europe
Most common off the coasts of Britain and Ireland but can also be seen from any headland facing the Atlantic. Also seen increasingly in Mediterranean waters.
Nests
From April and May in even, dense colonies, on cliffs, promontories and islands.
Eggs
1, white, laid in April to June. Incubation takes 43-45 days. Young fledge after 84-97 days. 1 brood per year.
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