The adults are large and heavy-bodied with long necks and a dagger-like bill. They are primarily white with a yellowish wash on the head and neck, and black flight feathers. Juveniles are the same size as the adults, but have brown plumage with white spotting. The white feathers signify maturity, around five years of age.
There are three (3) species of gannet. The Australasian gannet found around New Zealand, Victoria and Tasmania; the Cape gannet found on islands off the southern coast of Africa, and the largest representation is the Northern gannet.
The Northern gannet nests on offshore islands and inaccessible cliffs with a range from the North Sea to Canada. They are colony brooders and return to the same cliffs to lay their egg every year. Some colonies have been known to exist for centuries, such as Bass Rock, Scotland first noted in Anglo-Saxon times. The Northern Gannet is confined to the continental-shelf waters on both sides of the North Atlantic. In the eastern North Atlantic, it is distributed in 32 colonies from the coast of Brittany in France north to Norway, with its main concentration north and west of Scotland (Nelson 2002). In North America, it is restricted to just 6 well-established colonies: 3 in the Gulf of St. Lawrence, Québec, and 3 in the North Atlantic off the coast of Newfoundland.
Gannets reach sexual maturity around five years of age. They lay one chalky blue egg per year which is tended by both mother and father. Because they have no brood patch, they use their feet to keep the egg warm until it hatches. The parents tend their fledgling until it is three months of age providing regurgitated food for nourishment.
Their diet consists of fish and squid, and accidentally and fatally, of plastics which they confuse for something edible. Gannets are known for their spectacular plunge dives into the water, from heights as high as 100’, achieving speeds of 62 mph when they strike the water thus enabling them to reach depths underwater of 10-15 feet to pursue fish. They will also swim deeper in pursuit of their catch. They can then spear the fish with their sharp beaks, or preferably swallow them whole to be able to get up to the surface and not be harassed by other birds to surrender the fish. Gannets swim using their wings and feet—to propel themselves either deeper in pursuit or up to the surface.
Gannets can achieve these plunges due to a number of adaptations:
- no external nostrils, they are located inside the mouth instead;
- air sacs in the face and chest under the skin which act like bubble wrapping, cushioning the impact with the water;
- positioning of the eyes far enough forward on the face for binocular vision, allowing them to judge distances accurately.
- In many parts of the United Kingdom, the term "gannet" is used to refer to people who steadily eat vast quantities of food especially at public functions.
- The oldest recorded Northern Gannet was at least 26 years, 1 month old when it was found in Quebec.
- Once a northern gannet fledges from its nesting colony and is in the water, it is apparently unable to take off again for as long as two weeks. The bird is likely to begin its southward migration to the Gulf of Mexico by swimming, not flying.
While natural causes take their toll on the gannet population, plastics found in the ocean not only confuse gannets as being a possible food source, but also as seaweed for a nesting material. Adults and nestlings alike become tangled in fishing line and pieces of net, and other manmade detritus. Documentation shows birds becoming entangled at the nesting site and dying of starvation, or having deformities caused by fishing line confining body parts from development and possible limb loss. Oil spills are another manmade catastrophe. Oil on their feathers strips them of their natural waterproofing ability and starts a chain reaction of incapacitating events eventually leading to death.
Gannets are LARGE birds with long necks and very pointed beaks—a little smaller than a swan. Rescuers need to have eye protection, preferably safety glasses. If able, an agitated gannet will strike at the person’s eyes with its beak.
Make sure the container used for transport has high sides, i.e., large, deep storage container. Because the gannet needs “running room” to make headway, the rescue container does not need a snapped-on lid to keep it contained, but high sides are a must. A sheet or cloth draped over the container secured with duct tape, provides a necessary, adequate airflow as well as a confining effect. Adequate ventilation is a must because of the placement of their nostrils within their mouth.