Gannet
Gannets are seabirds comprising the genus Morus, in the family Sulidae, closely related to boobies. "Gannet" is derived from Old English ganot, ultimately from the same Old Germanic root as "gander". Morus is derived from Ancient Greek moros, "foolish", due to the lack of fear shown by breeding gannets and boobies, allowing them to be easily killed.
Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the North Atlantic, having a wingspan of up to. The other two species occur in the temperate seas around southern Africa, southern Australia, and New Zealand.
Gannets hunt fish by diving into the sea from a height and pursuing their prey underwater, and have a number of adaptations:
- They have no external nostrils; they are located inside the mouth, instead.
- They have air sacs in the face and chest under the skin, which act like bubble wrap, cushioning the impact with the water.
- The position of their eyes is far enough forward on the face for binocular vision, allowing them to judge distances accurately.
The gannet's supposed capacity for eating large quantities of fish has led to "gannet" becoming a description of somebody with a voracious appetite.
Mating and nesting
Gannets are colonial breeders on islands and coasts, normally laying one chalky-blue egg. They lack brood patches and use their webbed feet to warm the eggs. They reach maturity around 5 years of age. First-year birds are completely black, and subsequent subadult plumages show increasing amounts of white.Northern gannets
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, including the Shetland Isles. The rest of the world's northern-gannet population nests in Canada, Ireland, the Faroe Islands, and Iceland, with small numbers in France, the Channel Islands, Norway, and a single colony in Germany on Heligoland. The biggest northern-gannet colony is on Scotland's Bass Rock in the Firth of Forth; in 2014, this colony contained some 75,000 pairs.Sulasgeir off the coast of the Isle of Lewis, St. Kilda, Grassholm in Pembrokeshire, Bempton Cliffs in the East Riding of Yorkshire, Sceilig Bheag, Ireland, and Bonaventure Island, Quebec, are also important northern-gannet breeding sites.
Systematics and evolution
The three gannet species are now usually placed in the genus Morus, Abbott's booby in Papasula, and the remaining boobies in Sula. However, some authorities believe that all nine sulid species should be considered congeneric, in Sula. At one time, the various gannet species were considered to be a single species.Image | Scientific name | Common name | Distribution |
Morus bassanus | Northern gannet | North Atlantic on coasts influenced by the Gulf Stream | |
Morus capensis | Cape gannet | Southern Africa in three islands off Namibia and three islands off South Africa | |
Morus serrator | Australasian gannet | Coast of New Zealand, Victoria, and Tasmania |
Most fossil gannets are from the Late Miocene or Pliocene, when the diversity of seabirds in general was much higher than today. The cause the decline in species at the end of the Pleistocene is not clear; increased competition due to the spread of marine mammals may have played a role.
The genus Morus is much better documented in the fossil record than Sula, though the latter is more numerous today. The reasons are not clear; boobies possibly were better adapted or simply "lucky" to occur in the right places for dealing with the challenges of the Late Pliocene ecological change, or many more fossil boobies could still await discovery. Notably, gannets are today restricted to temperate oceans, while boobies are also found in tropical waters, whereas several of the prehistoric gannet species had a more equatorial distribution than their congeners of today.
Fossil species of gannets are:
- Morus loxostylus – includes M. atlanticus
- Morus olsoni
- Morus lompocanus
- Morus magnus
- Morus peruvianus
- Morus vagabundus
- Morus willetti – formerly in Sula
- Morus sp. – possibly M. magnus
- Morus sp. 1
- Morus sp. 2
- Morus peninsularis
- Morus recentior
- Morus reyanus – Del Rey gannet
Cultural references
Young gannets were historically used as a food source, a tradition still practised in Ness, Scotland, where they are called "guga". Like examples of continued traditional whale harvesting, the modern-day hunting of gannet chicks results in great controversies as to whether it should continue to be afforded "exemption from the ordinary protection afforded to sea birds in UK and EU law". The Ness hunt is currently limited to 2,000 chicks per year, and dates back at least to the Iron Age. The hunt is considered to be sustainable, as between 1902 and 2003, gannet numbers in Scotland increased dramatically from 30,000 to 180,000.
In "The Bookshop Sketch", originally from At Last the 1948 Show, a customer asks the bookshop proprietor for "the expurgated version" of Olsen's Standard Book of British Birds, "the one without the gannet", because he does not like gannets due to their "long nasty beaks". Desperate to satisfy the customer, the proprietor tears the page about the gannet out of the book.
In Series 1, Episode 3 of The F Word, Gordon Ramsay travels to the northwestern coast of Scotland and is shown how to prepare, cook, and eat gannet.