Galapagos Storm Petrels

Category: Sea Birds
Family: Hydrobatidae
Endemic Subspecies: Wedge-rumped Storm-petrel; Elliot's (or White-vented) Storm-petrel

Eight species of Storm Petrels have been recorded in Galapagos, including 3 resident species, 1 migrant and 4 vagrants. Storm-petrels are the smallest of the seabirds with tube-noses (raised nostril-tubes at the base of the bill). They have short to medium-length wings in proportion to their size and usually fly close to the sea with a characteristic gliding flight action interspersed with rapid wing beats. Storm-petrels have longish legs and webbed feet, and the species most likely to be seen in Galapagos are dark with white rumps. The sexes of all species recorded in Galapagos are alike, and immature plumages resemble adult plumage.

Scientific Name: Oceanodroma tethys
Family: Hydrobatidae
Length: 18 - 20 cm (7 - 7.8 in)
Wingspan: 50 cm (19.7 in)

Conservation Status: Near Threatened

Common resident; endemic subspecies tethys. Population estimated at c. 200,000 pairs in 3 colonies. Nests colonially in burrows or crevices, breeding throughout the year but mainly during the cold season (April to October).

Identification: A medium-sized, relatively long, narrow-winged storm-petrel. Upperparts uniform dark brown with paler brown bar on upper wing and large, triangular-shaped, pure white rump which extends almost to the tip of the tail and to the upper flanks and lateral under tail-coverts. Underparts dark, sometimes with ill-defined pale centre to under wings.

Behavior: Pelagic. Flight fast and rather forceful with deep wing beats and involving much banking and twisting, often high over the waves. Typically flies with wings held bowed and angled slightly forwards. When feeding skips and bounds over the surface, sometimes pattering on the water in a manner reminiscent of Elliot's Storm-petrel. Unique among storm-petrels in visiting the breeding grounds by day and feeding at night. Occasionally follows ships.

BAND-RUMED (OR MADEIRAN) STORM-PETREL

Scientific Name: Oceanodroma castro
Family: Hydrobatidae
Length: 19 - 21 cm (7.1 - 8 in)
Wingspan: 44 - 46 cm (17.3 - 18.1 in)

Uncommon resident of Galapagos. Population estimated at 15,000 pairs in 15 colonies. Nests in burrows or crevices, breeding throughout the year, with two different populations nesting in the same areas at different times.

Identification: A medium-sized storm-petrel with relatively broad, blunt-tipped wings; moderately long, slightly forked tail; and a rather 'bull-necked' appearance. The legs do not protrude beyond tail in flight. Upper parts uniform dark brown with paler brown bar on upper wing. Narrow, but prominent, 'U'-shaped white rump extends to the lateral undertail-coverts; at close range may show dark feathers at rear of white rump. Under parts entirely dark.

Voice: Silent at sea but calls at night near the breeding colony: a squeaky "whikka-whikka.." rather like rubbing a wet finger on a glass.

Behavior: Pelagic, feeding well offshore and rarely seen close to land. Flight action rather buoyant with rapid, shallow wing beats and low, shearing glides reminiscent of Audubon's Shearwater, with the wings held flat or slightly bowed. Progresses in a zigzag manner but occasionally becomes erratic, banking and 'jinking' and doubling back. Does not follow ships but sometimes attracted to lights at night. Visits colonies nocturnally.

ELLIOT'S (OR WHITE-VENTED) STORM-PETREL

Scientific Name: Oceanodroma gracilis
Family: Hydrobatidae
Length: 15 - 16 cm (5.9 - 6.3 in)
Wingspan: 40 cm (17 in)

Conservation Status: Data Deficient

Common resident of Galapagos; endemic subspecies galapagoemis. Population estimated at many thousands and although a nest has yet to be found in Galapagos, breeding is suspected to occur between April and October. These petrels are the ones seen most often during our Galapagos cruises.

Identification: A small storm-petrel with relatively short, broad-based and rather rounded wings, and a square-ended tail with feet protruding beyond tail in flight. Upperparts uniform dark brown, with paler brown bar on upper wings and a narrow but prominent, 'U' -shaped, pure white rump which extends to the rear flanks. Under parts dark with pale grey patch on centre of belly, and iII-defined pale bar on under wings.

Behavior: Pelagic, although often feeds close to shore. Feeds in a distinctive manner, fluttering and pattering on the water with wings raised. Often follows ships.