I noticed a short note to the letter page of Birdwatch magazine (June 2008 issue) from Steve Wood (New Zealand) drawing attention to a gadfly petrel he'd photographed in March 2006 near the Kermadec Islands, New Zealand, that is suggestive of Vanuatu Petrel Pterodroma occulta. The photo is reproduced on the Wrybill Birding Tours web site. It is not clear if there is a series of photographs and whether the bird struck him as unusual (e.g. small) in the field.
This very poorly known seabird was first described by Imber and Tennyson in 2001. Six specimens were obtained by the American Museum of Natural History (AMNH) Whitney South Sea Expedition in January 1927, near the Banks Islands but until more recently, not recognized as different from the very similar White-necked Petrel P. cervicalis. In 1983, an additional specimen was taken in northern New South Wales, Australia.
They are significantly smaller than White-necked and show a more expansive area of gray on the underside of the primaries and a broader dark leading edge to the underwing. White-necked Petrels typically show a less dark underprimaries (e.g. photo (Fig. 15) by Chris Collins on OceanWanderers taken on the 2006 WPO recce). However, a number of seasoned field observers have commented that the presence of darker primaries is not unique to the smaller form, a point that is also made from analysis of specimens in the Imber and Tennyson paper. Indeed, check out this wonderful shot taken by B Whylie on a Wollongong pelagic in March 2008. One interesting but tangential point is the repeated occurrence of pairs of very similar looking seabirds (often found together at sea) that differ markedly in size (Tahiti/Beck's, Fea's/Zino, Greater/Lesser Snow Petrel). What's up with that?
Some authors (e.g. Michael Brooke 2004) treat Vanuatu and White-necked as conspecific, at least until more is known, but the split has been acknowledged in the new Australian Checklist (Christidis and Boles 2008). An alternative name in the literature is Falla's Petrel in honor of the renowned ornithologist Sir Robert Alexander Falla. Obviously, seabirders in Australia and New Zealand are looking carefully at 'White-necked/Vanuatu' Petrels and I imagine more information will emerge, especially from birders visiting the waters around the Vanuatu islands. A dedicated chumming expedition, mirroring Hadoram Shirihai's rediscovery of Beck's Petrel in the Bismark Archipelago off Papua New Guinea, may be highly rewarding. I've seen it rumored on the web that Hadoram has photographed candidate Vanuatu's Petrels but have no other information. Perhaps he can chime in here?
The location of Wood's new sighting seems puzzling. The Kermadec Islands (specifically Macauley Island) are the world stronghold for White-necked Petrel with 50,000 nesting pairs, and relatively distant from the locations of the Vanuatuan and Australian specimens. Onley and Scofield (2007) speculate that the birds might breed on Mera Lava (where the types were collected in 1927) and other islands in the northern part of the Vanuatu archipelago. Mere Lava (sometimes spelled Mera Lava) is a small volcanic island 52 km southeast of Gaua in the Banks Group (-14.4629°, 168.042°).
Literature Citations:
Christidis, L. and Walter E Boles (2008) Systematics and Taxonomy of Australian Birds. CSIRO Publishing.
Imber, M. J. and A.J.D. Tennyson (2001) A new petrel species (Procellariidae) from the south-west Pacific. Emu 101 (2): 123-127.
Wood, S. (2008) Another 'lost' petrel found? Birdwatch June 2008 Issue 192, p21.
UPDATE (25 May 2008): See Comments tab (below) for a response from Hadoram Shirihai.
Cape May Warbler, Blue Grosbeak, Bobolinks - 2 Oct 2010
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In spite of the N-NNE winds and rain during the night, Hugh McGuinness and
I figured that Montauk Point might be a good place to look for migrants. We
were...
14 years ago
1 comment:
Re: the short note by Steve Wood/Dominic Mitchell in Birdwatch and Angus Wilson on Seabird-News.
www.wrybill-tours.com/idproblems/pterodroma1.htm
Dear Friends,
It is correct that I initially speculated (as Michael Imber probably did too, per the note in Birdwatch) that the petrel photographed by Steve Wood could be the poorly-known Vanuatu Petrel Pterodroma occulta. However, this was done before I had an opportunity to experience the two forms at sea and around the breeding grounds (i.e. White-necked Petrel Pterodroma cervicalis in the Kermadec Islands, and Vanuatu Petrel around Vanuatu), and also prior to examining the 6 specimens of occulta at the AMNH. In the future, I will be happy to share the results of these studies with others but not in this short response.
As it happens I sent to Steve Wood an email some time a go to say that Vincent Bretagnolle and I both think that the photographed petrel is NOT an occulta nor is it a cervicalis. Instead, we thought that it could be a member of the Collared/Gould's Petrel Pterodroma brevipes/leucoptera complex, but oddly enough with an underwing pattern and overall shape reminiscent of Black-Winged Petrel. However, the black on the head/cap looks too extensive for the latter. The apparent white collar is not conclusive, as this could possibly be an effect of wear. In fact, from this single photo taken at this angle, Steve Wood's petrel shows a combination of underwing, head and neck patterns that to my eyes (at least superficially) resembles the Atlantic's Black-capped Petrel Pterodroma hasitata, but it is impossible to know from this single image if it has white rump/upper-tail coverts as it should have for hasitata.
Now after experiencing the entire Pacific's Pterodroma taxa I can say that Steve Wood's bird has an odd combination of features that do not quite fit any one species. There seem to be four main possibilities (all are of equally possible, and other possibilities are welcome too): 1. that some of the odd characters are attributed to a 'photographic-trick' due to the angle of view, light conditions and partial wear/bleaching. 2. that the bird is a hybrid. 3. a vagrant petrel from another ocean, e.g. Black-capped Petrel (but don’t jump on me with a knife, I am simply suggesting that it superficially resembles that species from this angle, nothing more!!). 4. It is a completely new and undescribed species of petrel.
There is probably not much point in discussing the identity of this bird further until more examples are found, although I believe no one else has ever seen and/or photographed a similar petrel in the Pacific. We have to accept that some birds/images cannot be identified to a specific taxon, and thus should left unidentified. For me at least, Steve Wood's bird should remain as an unidentified Pterodroma.
As to Vanuatu Petrel, I feel, as with the rediscovery of the Beck's, that I should play safe here - i.e. follow a deliberate and careful approach and progress with the birds I am trying to identify at sea. And, yes I have tentatively identified Pterodroma occulta at sea in south Vanuatu, but would prefer not to publish my records until I gain further evidence and photos. I thank you for respecting this wish.
In relation to our book 'Albatrosses, petrels and shearwaters of the world: a handbook to their taxonomy, identification, ecology and conservation’, co-authored with Vincent Bretagnolle and illustrated by John Cox, for A & C Black, London', Vincent and I are planning major expeditions to Vanuatu, and we will be more than happy to share our findings with others.
I would like to add here that we are still have one extra space for the 'Fiji Petrel At Sea Expedition’. So far, only Tony Pym and Brent Stephenson showed interest in joining Dick Watling and I.
Thanks for your 'tubenose friendships'
Hadoram Shirihai
albatross_shirihai@hotmail.com
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