All species › Tubenoses › Petrels, shearwaters and diving petrels › Masatierra Petrel
Masatierra Petrel | Pterodroma defilippiana
De Filippi's stormvogel | Petrel de Masatierra | Grazina-de-masatierra
The Masatierra Petrel is a small, grey-and-white petrel of the genus Pterodroma that breeds only on islands off Chile. Outside the breeding season it disperses over the Humboldt Current to off Peru and Ecuador. It belongs to a group of small petrels with a dark eye mask and an M across the wings.
Voice
Silent at sea. In the colonies high, repeated calls at night.
No recording with a suitable Creative Commons licence is available for this species yet.
Identification
26 cm, a small, slender petrel with a short, thick black bill and long, narrow wings. The crown and hindneck are grey, the forehead is white and a prominent blackish mask runs through the eye. The upperparts are grey, with a dark M across the wings and back; the tail is grey with a darker tip. The underparts are white, with a grey half-collar on the side of the breast. The underwing is white, with a dark leading edge to the outer wing and a narrow dark trailing edge. It flies fast, in high arcs over the water. The sexes are alike.
Confusion species
Cook's Petrel Pterodroma cookii is paler grey, with a smaller eye patch and an almost entirely white underwing; at sea the two can be separated only with a good view of the head and underwing. Juan Fernandez Petrel Pterodroma externa and Galapagos Petrel Pterodroma phaeopygia are much larger, with a longer tail. Slender-billed Prion Pachyptila belcheri is bluer grey, with a white supercilium instead of a mask, and flies low over the waves.
Habitat
Open ocean and the cool water of the Humboldt Current, usually far offshore, sometimes over the continental shelf. It feeds on small squid, fish and crustaceans, picked from the surface in flight or while swimming. It breeds in burrows and rock crevices on the Juan Fernández Islands and the Desventuradas off Chile.
Where the bird is most at home, classified by the vegetation units of the Andes and the west coast.
Range and movements
In Peru at sea off the whole coast outside the breeding season, most numerous off the centre and south. In Ecuador scarcer, mainly off the south coast; rarely further north. Not in Bolivia. It does not breed in the guide area. Outside the guide area it breeds on the Juan Fernández Islands (Masatierra and Santa Clara) and on San Félix and San Ambrosio off Chile.
- Summer visitor (c. Apr–Sep)
- Winter visitor (c. Oct–Mar)
- Passage (Mar–Apr, Oct–Nov)
- dark = core range, pale = thinly spread
How and when to look
On pelagic trips a few tens of kilometres off central and southern Peru, often among other petrels and shearwaters; look for the dark eye mask and the underwing pattern.
Conservation status
Vulnerable. The species breeds on only a few small islands. Introduced rats, cats and goats, disturbance of breeding sites and bycatch in fisheries are threats.
Scientific name
Pterodroma defilippiana | (Giglioli & Salvadori, 1869)
Giglioli & Salvadori described the species in 1869 as Aestrelata defilippiana; because it was later moved to another genus, the author and year stand in brackets. The genus Pterodroma was introduced in 1856 by Bonaparte. The genus name comes from Greek pteron, 'wing', and dromos, 'runner', after the fast flight. The species name honours Filippo De Filippi (1814–1867), Italian zoologist and physician. The specimen the first description was based on came from Coasts of Peru and Chile.