Scopoli's Shearwater | Calonectris diomedea

Voice

Silent at sea. At the colony at night a loud, plaintive, rather baby-like wailing aaa-oow-aaa; the male higher and hoarser, the female lower and rougher.

Identification

Large, with long wings held slightly bowed and angled at the carpal. Upperparts dull grey-brown with faint scaling and sometimes a narrow pale band on the uppertail coverts; the head is grey-brown without a sharp cap, the underparts white. The bill is stout, pale yellow with a dark band before the tip. On the underwing the white of the secondaries extends well into the primaries, leaving only a narrow dark trailing edge; this is the best difference from Cory’s Shearwater. Flies with slow, supple beats and long glides, arcing high in wind; often in groups, resting in rafts on the water.

Confusion species

Cory’s Shearwater (Calonectris borealis), the Atlantic sister species that migrates along Morocco’s Atlantic coast in autumn, is slightly larger and heavier-billed and has dark primaries on the underwing up to the primary coverts; without good photographs they are often impossible to separate. Great Shearwater (Ardenna gravis) has a sharp dark cap, a white collar, a white band on the uppertail coverts and a thin black bill. Yelkouan Shearwater (Puffinus yelkouan) and Manx Shearwater (Puffinus puffinus) are much smaller, black and white or dark brown, and fly with fast, stiff beats.

Habitat

Open sea over the continental shelf and beyond, often with tuna shoals and dolphins and behind fishing boats. Breeds in burrows, rock crevices and under boulders on rocky islands and cliffs, coming ashore only after dark.

Range and movements

Breeds in Tunisia on Zembra and Zembretta in the Gulf of Tunis, where the colony was estimated in 2015 at about 142,000 pairs, by far the largest of the species, and on the La Galite archipelago; in Algeria on coastal islets such as the Habibas off Oran, and in small numbers on Libyan islets. Along Morocco’s Mediterranean coast and in the Strait of Gibraltar it is a numerous migrant; in autumn large numbers move out into the Atlantic and south along Morocco’s Atlantic coast, returning in spring. Non-breeders wander in summer to the eastern Mediterranean off Libya, Egypt, Israel and Lebanon. In Arabia a vagrant: about ten records in Oman, mainly in June and July, and a few in the Gulf of Oman off the Emirates. Beyond the region it breeds on islands throughout the Mediterranean and Adriatic and winters in the Atlantic off West and southern Africa.

• Summer visitor (c. Oct–Mar)
• Passage (Mar–Apr, Oct–Nov)
• dark = core range, pale = thinly spread

How and when to look

From the ferry or from Sidi Daoud on Cap Bon, flocks can be seen heading for Zembra evening after evening in summer. In the Strait of Gibraltar and from Cap Spartel near Tangier, thousands per hour sometimes pass in October.

Conservation status

Not globally threatened and, according to recent counts, far more numerous than once thought, but vulnerable in Europe because of longline bycatch, rats at colonies and light pollution. The Zembra colony is of global importance; after tracking studies the surrounding sea has been identified as a key area for protection.

Scientific name

Calonectris diomedea | (Scopoli, 1769)

Scopoli described the species in 1769 as Procellaria diomedea; because it was later moved to another genus, the author and year stand in brackets. The genus Calonectris was introduced in 1915 by Mathews & Iredale. Calonectris combines the Ancient Greek kalos 'good, noble' with the genus name Nectris, used for shearwaters by the German naturalist Heinrich Kuhl in 1820. diomedea refers to the Greek hero Diomedes, whose grieving companions were turned into white seabirds after his death. The specimen the first description was based on came from the Tremiti Islands, Italy.