About Calonectris diomedea (Scopoli, 1769)
Scopoli's shearwater (Calonectris diomedea, described by Scopoli in 1769) is 45–52 cm (18–20 in) long, with a 112–122 cm (44–48 in) wingspan. Its upperparts are brownish-grey, with most feathers fringed lighter brown; its wings are darker brown, upper tail-coverts have whitish tips, and its tail is dark brown. Most underparts are white, with a brown border most prominent on the wing's trailing edge. It has a pale yellow bill with a dark patch near the tip, and pale flesh-colored legs and feet. The sexes look similar, but the male is on average slightly larger than the female. This species looks very similar to Cory's shearwater, and the two can be difficult to distinguish; Scopoli's shearwater has more white on the primary feathers at the wingtip, particularly the outermost large feather (P10). The Cape Verde shearwater is smaller and significantly darker on its upperparts than Scopoli's shearwater. Scopoli's shearwater breeds on Mediterranean islands, from the Chafarinas Islands off the Moroccan coast in the west to the Greek Dodecanese islands in the east. The largest colony is on the rocky island of Zembra, 13 km (8.1 mi) off the Tunisian coast, holding between 141,000 and 223,000 breeding pairs—more than 75 percent of the global population. Other large colonies are on Linosa in the Strait of Sicily, and on the Balearic Islands. After the breeding season ends in late October, Scopoli's shearwaters migrate to the Atlantic, leaving the Mediterranean through the Strait of Gibraltar. They return to the Mediterranean at the end of February. Studies using light level geolocators found that birds tagged on Linosa or the Pantaleu islet in the Balearic Islands wintered in regions with major upwellings in the southeast Atlantic. The birds either foraged off West Africa in the Canary Current upwelling, or traveled further south to forage in the Benguela Current off the coast of Namibia. Scopoli's shearwater mainly eats small fish, and also consumes cephalopods and crustaceans. It feeds by skimming the water surface or surface feeding, and only rarely plunges completely below the surface. It sometimes follows whales and tuna to collect food scraps and catch small fish driven to the surface, and will also scavenge discards from fishing vessels.
