Balearic Shearwater: Medium-sized seabird with rather pointed wings and slender bill. Dark brown above, dark brown and white on underparts, and white wing linings. Light eye ring and grey bill. In flight, has heavy looking belly and toes that project beyond short tail. Critically endangered.
Range and Habitat
Balearic Shearwater: Summer visitor to areas of south England, western Wales, and the east coast from July through September. Migrates to the south of France and Balearic islands for breeding in summer. Can be seen plunge-diving for food or resting on the surface of the water in coastal areas.
Petrels and Shearwaters (Procellariidae)
There are four families of seabirds in the PROCELLARIIFORMES (pronounced pro-sel-lehr-EYE-ih-FOR-meez), an order that includes the dainty storm-petrels, the huge albatrosses, and the shearwaters.
The shearwaters are in the Procellariidae (pronounced pro-sel-lar-EYE-ih-dee), a family composed of eighty-five species in fourteen genera that roam all oceans of the world (IOC World Bird List, version 2.3).
In European waters, twenty-one species of shearwaters in seven genera have been identified. Included among these are the thin-winged Pterodrama species of the deep waters such as the Fea’s Petrel, and the stocky, gull-like Northern Fulmar.
Shearwaters are known for the prominent tube-like structures on their beaks that, as with all Procellariiformes, help remove excess sea water. Species such as the Sooty Shearwater are also known for their open water, low altitude gliding and tilting mode of flight on straight wings, the tips of which often slice or “shear" through the water’s surface.
Shearwaters are seabirds that are medium to large in size with elongated round bodies, medium length tails, long, pointed wings, and webbed feet adapted to their marine environment. Their bills are medium length, narrow, have a small hook on the tip, and have tubular structures on top.
This dull-coloured family is plumaged in dark browns, black, white, and grey. Some species such as the Sooty Shearwater are all dark with silvery wing linings, while others such as the Great Shearwater are dark above and light below. The Black-capped Petrel and related species have grey and white plumage with bold black markings on the head, back, and wings.
Shearwaters are encountered in deep, marine waters with the deepest waters beyond the continental shelf favoured by the petrels of the Pterodrama genus. They only occur on fresh water if blown inland by hurricanes, and on land are only likely to be encountered on cliffs and islets that are their breeding grounds.
Some species undertake very long migrations from breeding areas in the Southern Hemisphere to the waters of the Northern Hemisphere.
Shearwaters nest in colonies, and often occur in flocks when foraging. Fish, squid, crustaceans, and other food items are sometimes picked from the surface, but mostly obtained by diving into the water.
Populations of several species of shearwaters have been declining with subsequent listing as near-threatened or threatened; these declines likely linked to long-line fishing and global warming. Shearwaters are also easily threatened by disturbances at their breeding grounds. Factors such as these have caused such a large decline in already small populations of the Balearic Shearwater, that is has been listed as critically endangered.
Shearwaters produce an oily substance in their stomachs that is fed to young and which can be vomited as a defence mechanism. Young birds high in fat and oil content are harvested by the Maori people in New Zealand where they are called, “muttonbirds".