Possible Great-winged Petrel

[Tim Barnard]

I thought I'd share this for interest. I took these photographs at the Star of Bengal Banks on our return from the Kermadec Islands in April last year. I didn't pick it up at the time unfortunately. There was a lot going on.

It's the darkest faced GF/GW type Petrel I have seen so far in NZ waters. After a lot of thought and research, I submitted it as a probable Great-winged Petrel earlier this year. The RAC quite understandably didn't accept it as a first record however did consider it a possible. Splitting these birds at sea is problematic and more research is needed. I hope you find it as intriguing as I have.

All the best,

Tim

[Michael Szabo]

This photo from an Australian pelagic trip off Port MacDonnell shows one for comparison, taken by David Harper on 24 May 2022.

[phil hammond]

Note also the very steep forehead in Tim's bird

[Steve Wood]

If you were to adjusted the brightness, It shows the bird to be much paler around the face and in particularly on the forehead.
My thoughts, probably still too pale for p.macroptera.Also hard to see any detail on bill size/structure from these images or comparison of overall general size which would have been useful.

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[Tim Barnard]

Just for future reference, this is last photo I have. Thanks for your comments all.

[Tim Barnard]

Hi there,
I am still waiting for a convincing argument as to why this is a grey-faced petrel without manipulating photos. To me its more in the range of great-winged than grey-face. To get a record accepted the burden of proof rests with eliminating all doubt and the RAC has wisely called possible. Putting that aside, would this be accepted as a GF pet off western Aus or SA.

[Steve Wood]

Tim, there shouldn’t be any manipulating of any image but editing an image can be very important to show the true features.
Your image, to my eyes, is clearly underexposed so I adjusted the light level which was masking subtle details, especially around the key facial area. Not adding anything just highlighting what is true. The extensive pale forehead I believe is atypical for pt macroptera.
If you believe your bird is perhaps too dark for pt mac gouldi check out this image below. It was also taken on the same trip but for me still lacks the subtle difference of apparent finer bill, no obvious dark eye patch which is sometimes suggested as an ID feature, even though it has hardly any pale around the face, I believe still not what I would expect for pt macroptera.
I would like to think we would know one off the bat when we see a good one at sea.
Relying on anything less than a crisp detailed image is always going to be frustrating and certainly not going to fly with RBC for this species.

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Hope you get some more feedback on this bird Tim.

[Tim Barnard]

Thanks Steve,
Possibly another thread this. I've seen a few of these tan almost orangey looking GF Pets. I had one off Mayor with Russ, another at the Petrel Station with Scott and one on the Kermadec trip though not as strong as this. They often have darker faces too but clearly not GW material. Scott and I photographed a silvery one too recently. Vaguely reminiscent of a Prov Pet.

It's not only the extent of grey around the face that's variable in this species.

[Matthias]

Hi,

very interesting bird, Tim.

Just to add to the confusion, below I post a photo that shows
(left column) Grey-faced Petrel (North Island),
(right column) Great-winged Petrel (Australia),
(centre) an unusual bird that I photographed a while ago.

Based on jizz and especially the size and form of the bill, it looks more like a Great-winged Petrel, but it also shows a lot of white around the face. Howell and Zufelt (Oceanic Birds, p. 140) state that Great-winged Petrel can have a pale face.

What are your thoughts on this bird?

Cheers
Matthias

[Steve Wood]

For me, the centre bird is without doubt a grey faced Petrel and certainly not a classic Great winged Pet if you are basing the id on bill size and jizz. How extensive the amount of white should be the key feature for starters.
The overall body colour appears darker on the top right hand bird which doesn’t necessarily mean much when dealing with just images, but gives the impression of a different bird compared to the other two on the left.
Bill is slighter, especially when compared with the left hand bird but probably not outside the range and not a feature on it’s own to clinch the ID.
Can’t comment on the jizz as you have to be there.