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Interesting Gould's Petrel Pic

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Subject: Interesting Gould's Petrel Pic
From: "Dean Portelli" <>
Date: Wed, 17 Mar 2004 18:06:28 +1100
Hi all,

I recently found the following picture on the internet of a Gould's Petrel photographed off the Gold Coast on 16/3/2002, see www.indiabirds.com/obc/Content/ImagePage.asp?Bird_ID=1148&Bird_Family_ID=123 --- or go to --- www.indiabirds.com/obc/Default.asp and search for Pterodroma leucoptera or Gould's Petrel.

Once I saw this picture the underwing pattern immediately stuck out as unusual. I have seen many underwings of Gould's Petrel (all on land) and none have been as pictured in the photographed bird. The amount of blackish colouration on the coverts is much more extensive than what I am used to, and approaches that of Black-Winged or Mottled Petrel.

I am not disputing the identity of this individual, the extensive dark cap over the head and nape, extending in a relatively straight line from the suborbital patch to the side of the breast which is similarly dark, is diagnostic for P. leucoptera and P. brevipes. However, P. brevipes can be easily ruled out because of the colouring of the underside of the remiges.

According to Hanzab the areas on the underwing of P. leucoptera are described as such: Greater Primary Coverts - all white, except outer web of outer covert which is brown-grey. Median Primary Coverts - all white, except outer covert and outer web of next innermost (dark-brown). Marginal Primary Coverts - outermost coverts dark brown tipped white, rest white. Carpal Joint - marginal, lesser and basal halves of median coverts dark brown. Innerwing - from carpal joint diagonal bar extends three-quarters the length of the radius-ulna towards the body with distal halves of median coverts and narrow fringes of marginal coverts white. Rest of coverts white. I find the description of the innerwing a little confusing, there is no mention of lesser underwing coverts specifically, yet the claim is made that the rest of the coverts are white which would include the lesser coverts according to how this is written. Yet, the lesser coverts do form the diagonal bar, and from my inspection of the underwing of this species it is the median and lesser coverts that form the diagonal bar once it begins to thin out from the carpal joint, yet the coverts are not wholly dark (i.e. either have white bases - lesser, or white distal halves - median).

Anyway, getting to the point (concise writing is not my forte) the photographed bird does not conform to this description. It appears that all marginal and median primary coverts are dark brown, the greater coverts remaining white. On the innerwing the diagonal bar appears much thicker with perhaps all of the lesser coverts being dark and most of the median coverts (but this is very difficult to tell from the photo). Suffice to say that the underwing has much more dark colouration than is typical of Gould's.

In case anyone is wondering if the discrepancy could be attributed to the bird being a New Caledonian Petrel P. l. caledonica, especially given the bird was observed off SE QLD, then according to Hanzab the diagonal bar on nominate leucoptera is slightly heavier than in caledonica.

I welcome comments from seabirders experienced with Pterodroma petrels, particularly those who have seen Gould's at sea. What possible implications does this have for identification of Pterodroma petrels using the underwing pattern as a significant field ID feature?

One LAST thing - if you have come this far you are obviously interested in seabirds, so this Saturday (20th March) the Australian Bird Study Association in conjunction with SOSSA is hosting a Scientific Day entitled "The Tasman: a bird's sea" with lots of interesting talks on seabirds, this is to be held at Macquarie University. See www.absa.asn.au/comingevents.html for details. You can register on the day at the venue. Hope to see you there!

Cheers, Dean

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