[With thanks to Peter Pyle and Tony Pym.]New species - Bryan's Shearwater - summary
I have now received from Peter Pyle a draft of the paper. The manuscript is not yet finalised for publication in Condor in August, and so the final copy will not be ready for a month or two. Peter asks for patience, especially from colleagues seeking pdf’s. He has agreed that the summary below - my slant on reading the paper - can be posted:
This is a very small shearwater (if they were still grouped as Little Shearwater this bird could have been named the ‘Very Little Shearwater’). Consider, the wing measurement is 174 (and this a male… females of small Puffinus shearwaters are smaller) and compare this to a Manx Shearwater at 236 (mean). Those that have seen Macaronesian Shearwater would say that species is small, but this new species is smaller again. The morphometric data in the paper shows this new species is indeed smaller than any other known Puffinus taxon (and remember it is a male when comparing smaller females of other taxa).
The bird was collected in a burrow within a Bonin Petrel colony on Midway Island in 1963 so we must assume it was exploring the island (from breeding localities elsewhere in the Pacific?) though note that Hawaii has had a number of odd seabird records in the past, including birds from other oceans (for example, Jouanin’s Petrel).
The plumage is typical of Puffinus, showing slaty black upperparts, largely white underparts with dark feathering extending to the sides of breast and lower flanks. The undertail coverts and inner webs to the under primaries largely blackish, more typical of the Audubon's group, whereas the lores, auriculars, and supercilial region are white, more typical of the Little Shearwater group. The legs were blue, typical of the Little Shearwater group. ‘Typical’ being the operative word though, as we know now that the colour of undertail coverts in small shearwater can vary extensively within populations, that back colour can change with moult and age, and leg colour may vary from blue to pink or pale according to individuals (at least in Audubon’s and Tropical Shearwater anyway).
The new species is separable from other members of the genus by the combination of small size, proportionally long tail, dark undertail coverts and under primaries, and bluish colouration to legs.
The paper does not help with identification at sea. For example, (re my earlier question on Seabird-News), for Tropical and Bannerman’s Shearwaters the differences are only recorded as ‘much smaller size’ (remember male:female again) ‘and bluish leg colour’ (see above). Nothing more.
The bird showed a relatively large sequence divergence indicating its distinctness from all other taxa included in the study. It is closest in biometrics and appearance (but not genetics) to Atlantic boydi.
The bird has been named in honour of Edwin Horace Bryan, Jr., a participant in the Whitney South Seas Expedition in 1920-1923 and the Tanager Expedition to the Northwestern Hawaiian Islands in 1923-1924; Curator of Collections at the Bishop Museum, Honolulu, in 1919-1968; and author of many publications on Hawaiian insects and birds in 1926-1958.
Several committee members (and Howell) emphasized that this sighting could involve an undescribed taxon; the last chapter on the record may yet be written.
[Again, detective work courtesy of good ol' Ruskin , Surfbirds.]
PPS. I'm confused. Does this mean that 'Bonin Little Shearwater' (= bryani?) and the "very different" Bannerman's Shearwater (bannermani) both occur (breed?) in the Ogasawara Islands...???