Bass Rock​—Where Gannets Gather


MAMMOTH Bass Rock is some 350 feet [110 m] high and about a mile [2 km] in circumference. It stands offshore northeast of Edinburgh, Scotland, at the entrance of an estuary called the Firth of Forth. It is home to perhaps as many as 100,000 northern gannets, one tenth of the world population of this fascinating seabird. *

In the early 20th century, gannets were harvested as food. Their fat was used for medicinal purposes, and their feathers were valued for bedding. Some 300 birds were needed to provide stuffing for just one mattress. Their eggs, once viewed as a delicacy, are not generally considered palatable today.

Gannets may live for 30 years and usually mate for life. They are migrants, and in January they return to their same nest sites, which they defend vigorously. On Bass Rock these nests, made of seaweed and grass, are packed  together, some two to three feet [about a meter] apart. The birds prefer windswept sites, which enable them to make vertical takeoffs and landings.

Gannets are intriguing to watch. Sky-pointing​—stretching the neck with the beak pointing into the air—​indicates that the bird is about to fly off. Bending low​—facing another bird with outspread wings—​is a warning that it is prepared to defend its nest. Mating pairs fence with their beaks, and the female submits when her mate lightly bites her neck. Gannets breed one chick a year, and either parent will incubate the egg by placing a webbed foot on it to keep it warm.

The adult gannet is white, with distinctive black tips on its wings, which can span six feet [2 m]. The fledgling, in contrast, is black, flecked with small white spots. Within 12 weeks of hatching, the guga (as the young gannet is called) is heavier than its parents. It is equipped with extra layers of fat to fuel its eventual migration.

The young gannet begins its independent life when it first plunges into the sea, where it paddles on its own. However, most young ones do not survive the plunge, which amounts to a slide down the cliff face during which a wing or a leg is often broken. Those birds that alight safely on the water instinctively learn to fish. Eventually they migrate, often as far as West Africa, and they may not return to Bass Rock for three or four years.

The way gannets dive into the sea to fish is a wonderful sight. They reach speeds of 70 miles [100 km] an hour. Just before they plunge into the water from 100 feet [30 m] or so, their wings are drawn back to form an arrowhead and their nostrils are sealed. A protective membrane covers their eyes. At the same time, air sacs beneath the skin cushion the body from the shock of the impact, which may be so violent that spray is hurled high into the air. Fish are sometimes stunned by the impact.

When gannets are underwater, they use their wings and feet to weave about in catching their prey. They dine on mackerel, sprats, herring, and sand eels. They may fish for 30 hours or so at a time. Some gannets are known to fish as far east as the coast of Norway.

Bass Rock is also home to some ten other species of seabirds. But these are faced with the ever-expanding gannet colony, and they are hard-pressed to maintain a foothold. In times past, from about the 1400’s, Bass Rock was used by humans as a retreat for prayer and meditation. Later it was fortified and, for a time, became a penal colony. Although the lighthouse erected in 1902 is no longer manned, it still beams its warning light across the estuary.

The lighthouse keeper’s garden has long since returned to the wild, and now the gannets reign supreme. Popular boat excursions from the small port of North Berwick take visitors around the island for a close-up of the birds. It is a delightful trip​—if it is a calm day.

Even during the roughest storms, however, visitors need not be disappointed​—thanks to modern technology. A special video presentation at North Berwick’s Scottish Seabird Centre covers every aspect of life on Bass Rock. So whatever way a visitor chooses, he may watch these extraordinary divers of Bass Rock. The experience truly is memorable.


^ par. 3 The northern gannet’s Latin name reflects its Bass Rock origin. Today it is classified as Morus bassanus, or Sula bassana.

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Diving gannets reach speeds of 70 miles [100 km] an hour

[Credit Line]

© NHPA/Bill Coster

[Picture Credit Lines on page 26]

Two gannets: Stefan Ernst/Naturfoto-Online; background: Jörn Meier/Naturfoto-Online