The Northern Gannet
) is a seabird
and is the largest member of the gannet
Young birds are dark brown in their first year, and gradually acquire more white in subsequent seasons until they reach maturity after five years.
Adults are 81–110 centimetres (32–43 in) long, weigh 2.2–3.6 kilograms (4.9–7.9 lb) and have a 165–180 centimetres (65–71 in) wingspan. Before fledging, the immature birds (at about 10 weeks of age) can weigh more than 4 kilograms (8.8 lb). Their plumage is white with black wing tips. The bill is light bluish. The eye is light blue, and it is surrounded by bare, black skin. During breeding, the head and neck are brushed in a delicate yellow.
Gannets are colonial
breeders on islands and coasts, which normally lay one chalky blue egg. It takes five years for gannets to reach maturity. First-year birds are completely black, and subsequent sub-adult plumages show increasing amounts of white.
The most important nesting ground for Northern gannets is the United Kingdom
with about two thirds of the world's population. These live mainly in Scotland
and the Shetland Isles
. The rest of the world's population is divided between Canada
, Faroe Islands
, with small numbers in France
(they are often seen in the Bay of Biscay
), the Channel Islands
. The biggest Northern gannet colony is in the Scottish islands of St Kilda
; this colony alone comprises 20% of the entire world's population. Sulasgier off the coast of the Isle of Lewis
, Bass Rock
in the Firth of Forth
and Bonaventure Island
are also important Northern gannet breeding sites.
The Skellig Islands
off the south-west coast of Ireland
hold some 27,000 pairs of Northern Gannets, the second largest colony in the world.
] Systematics and evolution