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Bulwer's Petrel | Bulweria bulwerii
Bulwers stormvogel | Petrel de Bulwer
A small, all-dark petrel with long wings and a long, wedge-shaped tail, breeding on the Macaronesian islands just off the Moroccan coast. Even so it is rarely seen in Moroccan waters: eight records were known up to 2011.
Voice
Silent at sea. At the colony at night a low, repeated, dog-like barking hroo-hroo-hroo.
Recording: Marcel Gil Velasco — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
The size of a large storm petrel or a small shearwater, all blackish-brown, with a paler, brownish-grey diagonal bar across the upperwing coverts. The wings are long and narrow, held slightly forward and angled in flight; the long, pointed tail is usually held closed and looks like a spike. The bill is short, black and fairly stout; the legs are pinkish with dark toes. Flies low and erratically over the water with loose, flexible beats and short glides, more like a storm petrel than a shearwater.
Confusion species
Jouanin’s Petrel (Bulweria fallax) is very similar but occurs only in the Arabian Sea and the Gulf of Aden; it is larger, with a heavier head and bill, broader wings, a shorter tail and a slower flight. Band-rumped Storm Petrel (Hydrobates castro) and Leach’s Storm-Petrel (Hydrobates leucorhous) are smaller, with a white rump and shorter tail. Sooty Shearwater (Ardenna grisea) is much larger, with silvery underwings and a stiff flight.
Habitat
Warm, deep ocean far offshore, over the shelf edge and beyond; feeds mainly at night on small fish, squid and zooplankton at the surface. Rarely follows ships. Breeds in rock crevices and burrows on islands and islets.
Where the bird is most at home, classified by the habitats of North Africa and the Middle East.
Range and movements
In the region known only from Morocco’s Atlantic coast. In 2011 the Moroccan Rare Birds Committee accepted the eighth national record: a bird off Cap Rhir (Haha) on 16 June, the first June record. Most are seen from the coast or from boats between Essaouira and Agadir; further south, off Western Sahara, the species is probably more regular far offshore, but those waters are barely watched. Beyond the region it breeds in the Atlantic on the Azores, Madeira, the Desertas, the Selvagens, the Canary Islands and Cape Verde, and in the Pacific from China and Japan to Hawaii; Atlantic birds winter in the tropical Atlantic.
How and when to look
Pelagic trips from Agadir and summer seawatching at Cap Rhir offer the best chance. It is usually a single bird weaving low over the waves; the long, pointed tail and the ‘floppy’ flight are the best features.
Conservation status
Not globally threatened; the main threats at colonies are rats, cats and light pollution, which grounds young birds. In the region a rare vagrant that may be under-recorded because so few pelagic trips are made.
Scientific name
Bulweria bulwerii | (Jardine & Selby, 1828)
Jardine & Selby described the species in 1828 as Procellaria bulwerii; because it was later moved to another genus, the author and year stand in brackets. The genus Bulweria was introduced in 1843 by Bonaparte. Bulweria was formed from the specific name bulwerii and so honours the same man, James Bulwer. bulwerii honours the English clergyman, artist and naturalist James Bulwer (1794–1879), who collected the type specimen on Madeira. The specimen the first description was based on came from Madeira.