The Swinhoe's Storm-petrel or Swinhoe's Petrel (Oceanodroma monorhis) is a small seabird of the storm-petrel family Hydrobatidae.
It breeds on islands in the northwest Pacific off China, Japan and Korea. It nests in colonies close to the sea in rock crevices and lays a single white egg. It spends the rest of the year at sea.
Remarkably, following the trapping of a member of this species in Great Britain, a number of other individuals have been identified in western Europe.
This storm-petrel is strictly nocturnal at the breeding sites to avoid predation by gulls and skuas, and will even avoid coming to land on clear moonlit nights. Like most petrels, its walking ability is limited to a short shuffle to the burrow.
The Swinhoe's Petrel is a small bird, 18-21 cm in length with a 45-48 cm wingspan, but distinctly larger than the European Storm-petrel. It is essentially dark brown in all plumages, and has a fluttering flight, pattering on the water surface as it picks planktonic food items from the ocean surface. Unlike European Storm-petrel, it does not follow ships.
It most resembles in structure Leach's Storm-petrel, with its forked tail, longish wings, and flight behaviour, but does not have a white rump and the call differs. It is difficult to distinguish from other all-dark Oceanodroma species, and the first English record had to be DNA-tested to eliminate the possibility that it was a Leach's Storm-petrel, since some north-eastern Pacific Leach's Storm-petrels show all-dark rumps.
It is strictly pelagic outside the breeding season, and this, together with its remote breeding sites, makes the Swinhoe's Petrel a difficult bird to see from land. Only in storms might this species be pushed into headlands, but even then an out of range bird would probably defy definite identification.
This bird is named after the British naturalist Robert Swinhoe.
