Seen on June 6th 2002, approximately 4-5 km offshore (distance estimated visually and by calculation of boat speed and time from departure) from Busan shoreline.
Optics:: Leica 8x 32s.
Range:: Picked up about 100-150 m from the moving vessel; birds flew towards the vessel, banking across it at probably 20-30 m or less range.
Weather / Light: Light was good, with birds fully "lit"on the underparts during banking. Wind was probably a w force 3, with 1-2 m sea swell.
Two heavy-looking shearwaters, not too dissimilar from Streaked Shearwater Calonectris leucomelas in bulk or flight action were picked up through binoculars moving towards the vessel. Immediately it could be seen that both were largely dark overall, making identification a choice of Flesh-footed Puffinus carneipes, Short-tailed P.tenuirostris or Sooty Shearwater.
The flight was heavier than typical of Short-tailed and the bill was all dark,"obvious" and medium heavy, ruling out Flesh-footed Shearwater.
The tail also looked full, perhaps more tapering and longer than typically apparent on Short-tailed.
Structurally, the birds looked larger overall and more powerfully-built than Short-tailed with perhaps slightly broader wings and a distinctively less fluttery wing action, rather deep beats and strong glides.
As the birds banked close to the vessel, it appeared that the birds showed very obvious white panels on the underwing(much clearer than those on any Short-tailed I have seen), and both lacked an obvious paler chin that most/all Short-taileds show at such close range.
Although photographs were not taken, the 30 seconds or so close views the birds afforded led to the very confident identification as Sooty: it was only several days later that, looking at the Korean field guide, I realised that Sooty Shearwater had very surprisingly not actually ever been recorded in Korea before!
Previous experience of this and similar species
I used to see small numbers of Sooty Shearwaters annually in the UK (between 1981-1990). In addition I have seen several thousands from the Hokkaido-Tokyo ferry in Japan several times in the 1990s and several hundred thousand off California (with much smaller numbes of Short-taileds mixed in).
I have also seen several thousand Short-tailed Shearwaters off Japan, and tens of thousands off Australia. Most recently, in May 2002 I also recorded several in Korean waters.
We are grateful to both Dr Lee Hunsoo and Dr Park Jin-young for discussion of this record: both of these eminent Korean ornithologists agree that there are no earlier records of Sooty Shearwater, and that these two birds therefore appear to represent the first Korean records. We are very grateful for their input.