Fulmaro boreale

Identificazione

The northern fulmar has a wingspan of 102 to 112 cm (40–44 in) and is 46 cm (18 in) in length. Body mass can range from 450 to 1,000 g (16 to 35 oz). This species is gray and white with a pale yellow, thick bill and bluish legs. However, there are both a light morph and dark, or "blue," morph; in the Pacific Ocean there is an intermediate morph as well. Only the dark morph has more than dark edges on the underneath but they all have pale inner primaries on the top of the wings. The Pacific morph has a darker tail than the Atlantic morph.<p>Like other petrels, their walking ability is limited, but they are strong fliers, with a stiff wing action quite unlike the gulls. They look bull-necked compared to gulls, and have short stubby bills. They are long-lived, with a lifespan of 31 years not uncommon.

Tassonomia

The northern fulmar was formally described by the Swedish naturalist Carl Linnaeus in 1761 in the second edition of his book Fauna Svecica. He placed it with the other petrels in the genus Procellaria and coined the binomial name Procellaria glacialis. Linnaeus based his description mainly on the "Mallemucke" that had been described and illustrated in 1675 by the German naturalist Friderich Martens in his account of his voyage to Spitzbergen. The northern fulmar is now placed in the genus Fulmarus that was introduced in 1826 by the English naturalist James Stephens. The genus name comes from the Old Norse Fúlmár meaning "foul-mew" or "foul-gull" because of the birds' habit of ejecting a foul-smelling oil. The specific epithet glacialis is Latin for "icy".<p>Three subspecies are recognised:

Nome scientifico

Fulmarus glacialis

Autorità

(Linnaeus, 1761)

Ordine

Procellariformi

Famiglia

Procellaridi

Genere

Fulmarus

Areale e habitat

Areale riproduttivo

NA, PAL : is. and coasts of North Atlantic, bays between Arctic and North Atlantic, and North Pacific including Sea of Okhotsk and Bering Sea

Areale non riproduttivo

to coasts of nw Pacific s to Japan, ne Pacific s to Baja California (nw Mexico), w Atlantic s to North Carolina, e Atlantic s to France

Migrazione

Complete migrants

Comportamento

This fulmar will feed on shrimp, fish, squid, plankton, jellyfish, and carrion, as well as refuse. When eating fish, they will dive up to several feet deep to retrieve their prey.<p>The northern fulmar starts breeding at between six and twelve years old. It is monogamous, and forms long-term pair bonds. It returns to the same nest site year after year. The breeding season starts in May; however, the female has glands that store sperm to allow weeks to pass between copulation and the laying of the egg. During the breeding season adult Fulmars usually remain within 500 km of their breeding colony instead of traveling up to thousands of kilometers while searching for food. Their nest is a scrape on a grassy ledge or a saucer of vegetation on the ground, lined with softer material. The birds nest in large colonies Recently, they have started nesting on rooftops and buildings. Both sexes are involved in the nest-building process. A single white egg, 74 mm × 51 mm (2.9 in × 2.0 in), is incubated for a period of 50 to 54 days, by both sexes. The altricial chick is brooded for 2 weeks and fully fledges after 70 to 75 days. Again, both sexes are involved. During this period, the parents are nocturnal, and will even be inactive on well-lit nights.<p>The mating ritual of this fulmar consists of the female resting on a ledge and the male landing with his bill open and his head back. He commences to wave his head side to side and up and down while calling.<p>They make grunting and chuckling sounds while eating and guttural calls during the breeding season.

Conservazione

The northern fulmar is estimated to have between 15,000,000 and 30,000,000 mature individuals that occupy an occurrence range of 28,400,000 km2 (11,000,000 sq mi) and their North American population is on the rise, hence it is listed with the IUCN as Least Concern. The range of these species increased greatly last century due to the availability of fish offal from commercial fleets, but may contract because of less food from this source and climatic change. The population increase has been especially notable in the British Isles.

Tendenza della popolazione

rising