Date: 12/1/18 2:58 pm
From: David Irons <llsdirons...>
Subject: [obol] Re: Strange Grebe
Greetings all,

Nagi sent me his grebe photo directly. I think there is little doubt (none in my opinion) that this bird is a partially-grown hatch-year Western Grebe. The bill color fits Western and really nothing else other than Red-necked Grebe (which it isn't). The pattern of dark on the head and where it meets the base of the bill matches Western quite well. The downy feathering on the hindneck supports the apparent age.

Western Grebes can produce young well into the fall season, which has always come as a surprise for me. I've seen tiny "riders" (very small recently-fledged juvs.) still on a parent's back into late September at Fern Ridge Res.

It's pretty easy to eliminate juv. Red-necked Grebe, because young birds retain a stripe-headed look until at least full-grown. Horned Grebe is also eliminated based on the bill color, which is variable, but never this yellowish and straw-colored. Also, in all plumages and at all ages (even juveniles) Horned Grebes have a tiny pale ivory tip on the bill that this bird lacks. This pale tip is a great field mark if you have a basic plumaged bird that is an Eared/Horned type. Horned Grebe has a pale tip to the bill and Eared does not. Finally, in all basic plumages (even juveniles) Horned Grebes have a narrow strip of red between the eye and the base of the bill that wraps under the base of the bill.

Dave Irons
Beaverton, OR
________________________________
From: <obol-bounce...> <obol-bounce...> on behalf of Jeff Gilligan <jeffgilligan10...>
Sent: Saturday, December 1, 2018 10:21 PM
To: sean mcallister
Cc: <baro...>; Nagi Aboulenein; obol
Subject: [obol] Re: Strange Grebe

I hadn’t noticed the down, or the comment about it in the original post. Maybe it is a Western…..really surprising for December.

Jeff Gilligan




On Dec 1, 2018, at 2:17 PM, sean mcallister <whiteouters...><mailto:<whiteouters...>> wrote:

With that much down in the plumage, I'll go with Western. The bill shape and color both work. Bill size and overall size are also probably right for Western of that age. If it was a Horned, at that age, we could probably expect to see the facial stripes expected in all young Podiceps grebes.

Sean McAllister

On Sat, Dec 1, 2018 at 12:00 PM Robert O'Brien <baro...><mailto:<baro...>> wrote:
Well, it's the battle of the photos.
The photo from here: http://animalia-life.club/other/western-grebe-baby.html
(23rd counting left to right top to bottom is of a subadult western grebe) is an about 1/2 grown Western.

The attached is an overlay of Nagi's and Greg's photos, size adjusted.
Note the difference not in length (could be accounted for by age) but in shape.
Western is long, narrow and very pointed. But Horned is proportionately thicker and more rounded (blunt) at the end.
The shape shown by Nagi's is consistent with Jeff's photo as well, although the bill is shorter due to juvenility.

Bob OBrien


On Sat, Dec 1, 2018 at 10:15 AM Jeff Gilligan <jeffgilligan10...><mailto:<jeffgilligan10...>> wrote:
I know this is a photo of a Western Grebe that accentuates the bill length, but I think it is a good illustration of how long and thin their bills are: http://www.birdspix.com/wp-content/uploads/2012/01/Western-Grebe-575-cr.jpg

Here is a Horned Grebe with a fairly yellow bill: http://3.bp.blogspot.com/_x29Pef-T4FQ/SBDMpa7vuFI/AAAAAAAAELc/Gwt8kcorI0k/s400/MN07+horned+grebe+100_8675.jpg

Jeff Gilligan



 
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