Seabirds on Tonga SG 1339 featuring the tail of a Hump-backed Whale
SG1339 issued in 1996   Detail of seabirds on SG 1339
SG 1339   Detail
Herald Petrel Polynesian Storm-Petrel - dark morph
Herald Petrel - dark morph Polynesian Storm-Petrel - dark morph
The Stanley Gibbons catalogue, Stamps of the World, lists this stamp as showing Herald Petrel (Pterodroma arminjoniana). According to Peter Harrison's "Seabirds, an identification guide" (Croom Helm, 1985), the Herald Petrel breeds on one of the islands of Tonga, Chesterfield Island, so I bought the set of WWF stamps issued by Tonga in 1996 showing Hump-backed Whales, expecting to have a new species for my collection.

After examining the birds on the stamp and comparing them with the illustrations of Herald Petrel in Harrison, I was sure that the birds were not of this species. The Herald Petrel is shown with a wedge-shaped, pointed tail, but the birds on the stamp had forked tails. A look for dark fork-tailed petrels likely to be around Tonga eventually led to the dark morph of the Polynesian Storm-Petrel (Nesofregetta fuliginosa).

Does anyone have any further views on this?

Added 23rd  July, 2000