Friday 18 November 2011

Grebe - worth a second look and a bit more research

I've ben trawling through pics of Red necked Grebe on the net this evening and agree that the Anglesey bird is a very interesting one. There is a lack of quality pictures of winter RN Grebe in general especially those noting 1st winters. Following Chris jones' sharp eye bringing the possibility to our attention and Steve stating on this blog his uneasiness about the bird, I decided to email two i.d. guru's - Martin Garner and Killian Mullarney. Both responded kindly within hours and I'm sure they won't mind me sharing their thoughs with you....

Martin responded in his e-mail-
''Eek! not an easy subject and one I haven’t bottomed out on. I came to the conclusion a while back that first winters probably weren’t identifiable and perhaps extreme adult winter might be. Aging I think also includes iris colour (pale yellow on first winter) more brown in secondaries on first winter and obvious white spur at rear of cheeks lacking on first winter. Your bird looks like it probably is a first winter (probably the first thing to establish with certainty) and as Killian has indicated European birds in first winter and some stages of adult have more extensive yellow. I think some, specifically adult winter holboelli, may have an extent of yellow on the bill beyond that which can be found in Europe birds but it’s a bit of a weak character and needs more research/ data. When I compared skins directly several years ago, adult holboelli in winter also seems to have cheeks of v similar degree of darkness to the crown (slightly paler/ more contrasting on European birds).
As KM has indicated, I also agree the bill does look extraordinary in the pics which is what I guess has most aroused interest.
So bottom line- get some feathers or excrement if it preens and poos –preferably in place where such activities are not commonly shared with other species!
I would at least try and observe it well and record and photograph as much detail as possible. We are always discovering new things with these subtle taxa- so you never know.. ''

While Killian responded by writing:-
''I’m afraid I don’t have sufficient experience or knowledge of holboellii to be able to offer an authoritative opinion on this interesting bird. What impresses me most about the Anglesey bird is the extraordinary length of the bill, a significantly longer bill (compared to European R-n Grebe) being one of the more important characters of holboellii. The extensive yellow colour of the bill is not, I believe, very significant, as 1st-year European Red-neckeds have a mostly yellowish bill up to around mid-winter, as do autumn adults (though I’m not sure until when). A thin yellow iris is a feature of 1w Red-necked Grebes (both populations) and I think there might be a hint of that in the second photo.''
Thanks to them both for their valuable and interesting feedback.

Below are a number of photos from America and Europe of RNGrebe so that we can compare bill structures and length. I know which one I think the Llyn Penrhyn bird looks more like. Click on the picture for bigger images.

The above bird was found dead by Liz Snell at Ynys Las yestreday. Although the angle isn't good the bill looks pretty small.
Above - This bird was taken at llandegfedd reservoir. Although pretty lengthy conmaped to the size of the head, the structure looks different and the bird less hunched than photos of the penrhyn bird.

Above - This bird was at Pennington Flash. The bill looks tiny compared with the Penrhyn bird.

Above - Red necked Grebe (holboellii) taken in USA.

Above - Red necked Grebe (holboelli) taken in USA - bill structure is long and bulkier at base - more like the Penrhyn Bird.

Above - Steve's pic. Note the length of the bill. Even with a hunched posture the length of bill is equal if not wider than the head.

Above - Rob's pic - as in Steve's pic the bird is in a hunched posture that would make the head wider than if it had it's necked stretched. The bill is again at least longer than the width of the head.

Above pic - Finally a monster of a bll from a summer plumaged bird taken in Alaska.
Even though this bill is very thick and long it's certainly closer in structure to our bird than, for example the pennington bird above.

As Steve says below, it would be great to get other's opinions. Any more pics, videos or even feather and droppings samples from this weekend would be great.

Sorry to any photographers who I have 'solen' their images above. If you are cross with me and would like me to remove them, let me know and I'll delete them immediately.

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