|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?