Wilson's Storm-Petrel (Oceanites oceanicus)

Indonesian-Petrel badai pantat putih

Description: very small (18 cm) black and white petrel. Upperparts black with grayish wing bar and a conspicuous white rump bar formed by white upper tail coverts; underparts sooty brown. The feet protrude just beyond the short square tail in flight. Iris-dark; bill; black; feet – black with yellow webs.

Voice: twittering and piping calls at breeding sites but only a faint peeping by feeding birds at sea.

Distribution and status: breeds in Antartic but migrates over almost all the world’s oceans. Occasionally seen over Javan and Bali waters.

Habits: flies singly or in small parties low over sea with short glides interspersed with loose wingbeats, tilting and rolling from side to side. When onto food it hovers and paddles on the water with its long feet. Often follows ships.

Diet: fish, plankton, crustacean floating scraps.

Race: O.o. exasperatus

Storm-petrels-Family Hydrobatidae

A small family oceanic birds similar to shearwaters but smaller with a more fluttery flight and with the nostril tubes joined into a single aperture.

Storm-petrels are the smallest oceanic birds and their weak butterfly like flight and habit of hovering and treading the water with their webbed feet makes them easy to recognize from other seabirds.
Storm-petrels feed on small crustaceans or floating organic debris. They nest in rock crevices and burrows on rocky shores and islands.
Individual species are often difficult to distinguish but only two species are recorded for Javan waters.
Key to Javan Storm-Petrels
Rump white………………………………………….Oceanites oceanicus
Rump dark grey……………………....................Oceanodroma monorhis
source: Mckinnon. Java and Bali. Gadjah Mada University Press. Jojakarta