Animalia Life

Morus bassanus
TAXONOMY
Pelecanus Bassanus, Linnaeus, 1758, Bass Rock, Scotland. Monotypic.
OTHER COMMON NAMES
English: (North) Atlantic gannet; French: Fou de Bassan; German: Basstцlpel; Spanish: Alcatraz Atlбntico.
PHYSICAL CHARACTERISTICS
34.3–39.4 in (87–100 cm); 5.1–7.9 lb (2.3–3.6 kg); wingspan 65–70.9 in (165–180 cm). Largest of sulids, a strong bird with mainly a strikingly white plumage. Compared with other gannets, bill is slightly stouter and head is paler cream. Juveniles mainly dark brown, gradually gaining white feathers of adult plumage.
DISTRIBUTION
Exclusively in the north Atlantic, where breeds on both sides 46–72° north. More widespread on eastern side, where in winter also enters the Mediterranean Sea and disperses south to subtropical waters. On western side, breeds on islands off Newfoundland and in the Gulf of St. Lawrence (Canada) and disperses south in winter to the Gulf of Mexico.
HABITAT
Strictly marine, mainly in waters over the continental shelf. Breeds on cliffs on offshore islands or, more rarely, on mainland.
BEHAVIOR
Breeds in dense colonies where aggressiveness and intense social
BEHAVIOR
have given way to complex repertoire of stereotyped displays. Breeding birds acquire a nest-site, which they then defend against intruders and maintain from year to year. Pair
BEHAVIOR
is equally complex and linked to the nest-site. At sea, often occurs in groups particularly congregating around rich feeding sources but with little interaction.
FEEDING ECOLOGY AND DIET
Feeds on shoaling pelagic fish like herring (Clupea), mackerel (Scomber) and sprat (Sprattus), also sandeels (Ammodytes). Makes spectacular plunge-dives from great heights. Also regularly attends trawlers.
REPRODUCTIVE BIOLOGY
Highly seasonal, starting March through April. Forms large colonies on cliffs or on flat ground, where builds large nest of seaweed, grass, etc. and a significant amount of excreta. Lays one egg only, incubated by both parents for 44 days. Chick fledges at 90 days; on its own, after it has been deserted by parents. Does not breed until four to five years old.
CONSERVATION STATUS
Not threatened. Abundant and widespread throughout its range. Protection of breeding sites and cessation of former direct exploitation of chicks (for food) led to significant recovery over most of twentieth century. Overexploitation of fisheries remains an important threat; also suffers some degree of incidental mortality at sea.
SIGNIFICANCE TO HUMANS
Chicks used to be taken for food in some local communities, a practice that still continues in a few places (e.g., Sula Sgeir, off Scotland). Also present in literature and art. Nowadays colonies may constitute important sources of income locally, as tourist activities are developed around them.

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