Northern fulmar, Fulmarus glacialis.
Northern Fulmar, Fulmarus glacialis
The northern fulmar's basic body shape is similar to that of a gull, but its neck and head are thicker and heavier and its wings are narrower. Its beak is generally yellow, short, and hooked, but members of the North Atlantic population, which may be a subspecies, have longer beaks. The northern fulmar nests on cliffs above the open ocean, which is unusual in this family. It forms huge colonies of up to 200,000 individuals, with females laying one egg on a ledge of bare rock or on any available vegetation.
The northern fulmar is a bird often studied for its arctic adaptations, such as its two colour phases. The light phase, characterized by a white body with grey wings, tail, and rump, increases in prominence with increased latitude. This may represent an adaptation for conserving heat, as white plumage warms the bird by reflecting the heat radiated by its body back to its skin. Colonies located farther south all exhibit the dark phase of coloration, a deep grey-blue. In between these extremes the colonies are a mixture of the two colour phases. In Europe, by contrast, southern populations of fulmars are light coloured, while the more northern populations are dark. This inconsistency between continents is as yet unexplained!
The northern fulmar breeds mainly in the Arctic and until recently, its range was confined here. In the last hundred years, however, this species has expanded its range in the North Atlantic to include Iceland, Norway, and the British Isles. Most scientists believe that this spread can be explained by the expansion of the fishing industry. Although the fulmar normally feeds on plankton, the small invertebrates that float in ocean waters, this species has learned to exploit the waste found around fishing ports. The guts and other scraps thrown into the sea from trawlers have become a major source of food. The fulmars that disperse to these new areas tend to be the juveniles, as the older individuals seem to be attached to more traditional nesting sites.
Fulmars have a lengthy breeding cycle. Parents incubate a single egg for about fifty days, the male and female taking turns every four or five days. Their nesting habitat permits this long incubation although arctic summers are short, seaside cliffs are rarely snow covered, and are suitable for nesting as soon as the weather begins to become milder in the spring. Northern fulmars remain juveniles for eight or nine years, but once maturity is reached, reproduction can continue for a further 20 or 30 years! The exact life expectancy of the northern fulmar is unknown, but the numerous offspring each bird can produce in its lifetime may be one explanation for this species' success in the harsh arctic environment.