Northern Gannet (Morus bassanus)

That’s because Gannets catch their food in a distinctive and lavish style. They are fish-eaters, like many a seabird, but have eschewed the majority method of submerging from the surface in favour of a more dramatic approach – a headlong plunge from high above the waves. They soar into the air to a height of between ten and forty metres, stall for a moment and then, with wings closed, plummet into the sea. They hit the water with a splash and their momentum takes them a metre or two down underwater, where hopefully the shoal of fish they had spied from above will still be swimming. With flaps of their wings and kicks of their fully webbed feet, they will grab a fish up to 30cm long with their saw-edged bill before rising again to the surface.

Plunge-diving is quite a specialised pursuit, and the Gannet shows several special adaptations for it. Its eyes are relatively forward-facing, giving it overlapping (binocular) vision, which is necessary for judging distance before taking the plunge. It also has nostrils that open inside, not outside the bill – literally to prevent water rushing up its nose! And the Gannet is also fitted with inflatable air-sacs between its skin and muscle to reduce the impact of its momentous dives.

Gannets are highly sociable birds, and they often feed in flocks several hundred strong. (Being on a boat among a flock of plunging birds is one of the great experiences of birdwatching). They also form colonies when breeding. The largest colony, on St Kilda, off the west coast of Scotland, held 60,428 nests in 1994, and at least three other colonies in Britain also hold more than 20,000 nests. These are impressive numbers, but as a whole the Gannet’s distribution is quite restricted, with fewer than 60 colonies in the world. Gannets are such large birds that they can only breed in places with enough constant updraft to allow them to take off, and such sites – in windy stacks and tall cliffs – are at a premium.

In common with many seabirds, Gannets lay only one egg. Unusually, though, it is not incubated under the birds’ belly, for Gannets have no brood-patch (special patch of bare skin for incubation). Instead the parent bird literally stands on the egg, exposing it to the rich blood vessels in the webs of its feet and covering it up. The egg duly hatches after forty days or so, and the resulting nestling then moves upstairs, so to speak, to rest on the surface of its parents’ feet.

Habitat Breeds on islands and sea-stacks, or cliffs. Winters at sea, mainly in shallow water above continental shelf.
Food Mainly fish, obtained in spectacular plunge-dive.
Movements Partially migratory. Most attend breeding areas from January to about October. First years and some adults disperse south to West African waters for winter, and the first years may not come all the way back in the subsequent breeding season.
Voice A rumbling honking mainly heard at the colony.
Pairing style Monogamous, and pair for life, renewing pair bond each year.
Nesting In large, densely-packed colonies, from a handful to about 60,000 pairs.
Nest Large pile of seaweed, grass, feathers and earth, bound together with birds’ excreta.
Productivity 1 brood a year.
Eggs 1.
Incubation 42-46 days, by both parents, under their feet.
Young Nest-bound and naked at first, but down acquired in first week.
Parenting style Both parents feed young by regurgitation.
Food to young Mainly fish.
Leaving nest Fledges at 84-97 days, having been left by the parents about 10 days previously. The newly fledged juveniles take to the sea alone and swim for their first few weeks, dispersing this way up to 72km until they can fly.