Balearic Shearwater

The Balearic shearwater, Puffinus mauretanicus, is a medium-sized member of the seabird family Procellariidae. With a length of 34–39 cm and a wingspan of 78–90 cm, it exhibits the characteristic shearing flight pattern of its genus, gliding gracefully over the sea surface with stiff wings. The bird's plumage transitions from dark brown to dirty white, revealing its dark upperparts and paler undersides as it banks and turns.

Identification Tips

This species can be recognized by its flight pattern, which resembles a flying cross with wings held at right angles to the body. It is similar in appearance to the Manx and yelkouan shearwaters but can be distinguished by its less contrasting plumage. Identification may require a combination of morphological characteristics and DNA sequence data.

Habitat

The Balearic shearwater breeds on islands and coastal cliffs within the Balearic Islands.

Distribution

While most individuals remain in the Mediterranean Sea, some venture into the Atlantic during late summer, reaching as far north as Great Britain and Ireland.

Behaviour

This gregarious bird can often be seen in large flocks from boats or headlands, particularly in autumn. Silent at sea, its breeding colonies come alive at night with a chorus of raucous cackling calls, higher pitched than those of the Manx shearwater.

Breeding

The Balearic shearwater nests in burrows and caves, which are exclusively visited under the cover of darkness to evade predation by large gulls.

Diet and Feeding

Its diet consists of fish and molluscs, and unlike some seabirds, it does not typically follow boats to feed.

Conservation status

The IUCN lists the Balearic shearwater as Critically Endangered. It faces threats from habitat destruction due to resort development, light pollution, predation by introduced species, and potential hybridization with yelkouan shearwaters. Conservation efforts are complicated by the multitude of languages spoken across its range, which can hinder communication and collaboration. The species is protected under the Agreement on the Conservation of Albatrosses and Petrels.