Date: 12/23/18 11:25 am
From: Noah Strycker <noah.strycker...>
Subject: [obol] Re: White Egret
Hi all,

I guess I have about as much experience as anyone on this list with
Intermediate/Great egrets in other countries... which is to say I've
wrangled with these birds a few times before, for better or worse ;)

First, it seems to me that gape extent is helpful as a supporting feature
but can be very difficult to judge without a point-blank view (as others
have pointed out). Facial feathers often obscure the narrowing rearline of
the gape on Great Egrets, making it appear shorter than it really is. There
are many images on eBird showing this variation. For instance, look closely
at the gape on these Great Egrets, all photographed in the US in the past
few days - none of them appears to project behind the eye:

https://macaulaylibrary.org/asset/130535571
https://macaulaylibrary.org/asset/130451321
https://macaulaylibrary.org/asset/129885791
https://macaulaylibrary.org/asset/129653601

As for our bird, I guess I would hazard a rather small/variant Great Egret,
which incidentally is overwhelmingly more likely than a hemispherically
misplaced Intermediate Egret. In Sally's last photo it shows the classic
"kink" in the upper neck typical for a Great Egret, instead of the gently
symmetrical S-curve an Intermediate should have, although even this field
mark can be subtle. I've seen unusually small Great Egrets in Oregon
before, and they are known to have significant size variation, especially
between males and females; heavier birds may weigh almost three times as
much as lighter birds according to published studies. All birds show
individual variation, of course, and I can remember cases of confusingly
small gulls and other species in the past. See this interesting post from
Sibley:

http://www.sibleyguides.com/2012/01/do-dwarf-birds-exist/

It's probably safest to leave this bird simply as "white egret sp," at
least for now. Remember also that not all birds are safely identified, no
matter how loud some voices in the room. I still have no idea about the
infamous white egret <https://ebird.org/view/checklist/S39201795> (seen by
many) at Malheur - even after studying it for an hour from literally 10
feet away, it had almost-equal characteristics of Snowy Egret, Cattle
Egret, and Little Blue Heron!

But to indicate that this discussion is settled, or that "experts" have
called our bird an Intermediate Egret, is misleading and unhelpful,
especially when detailed comments like the one pasted below (from the
Facebook ID group, and the most informative perspective I've seen about
this bird by someone who has really studied these species) are being
offered:

Personally I wouldn’t ID this one as an Intermediate and from what I see, I
would suggest that this is a runt Great egret. To me the bill looks too
long for Intermediate for a start but it’s mainly some subtle details of
the head that strongly point towards a Great egret. There is a noticeable
difference in the size of the eye between the 2 sp, with Intermediate
sporting a comparatively larger eye. Check out a few pics on the web (make
sure they are correctly identified though...) and you’ll see it’s quite
obvious once you have your eyes tuned into it: the eye of a Great egret
appears tiny compared to Intermediate. The shape and colour of the loral
bare skin patch is very useful and readily visible on the Oregon bird: it
is somewhat narrow and thus looks rectangular rather than square. In
Intermediate the loral patch is wider and thus appears square. The
combination of these 2 features (eye size, shape of the loral patch) give
to each sp a distinctly different facial expression once you know what to
look for. I would also add that the lores don’t look especially yellow on
the subject bird (rather greenish) and, perhaps more importantly, they
sport at their bottom a black line that runs along the edge of the upper
mandible: a typical feature of Great egret, as opposed to old world Great
white egret, that was first brought to light by Sébastien Reeber as a
possible feature that would help and separate nearctic birds from European
birds. - Thibaut Chansac

Merry birding,

Noah Strycker


On Sun, Dec 23, 2018 at 9:12 AM Sally Hill <1sallyhill.9...> wrote:

> I have been following that discussion. Interesting.
>
> Sally Hill
>
>
> On Dec 23, 2018, at 9:04 AM, Alan Contreras <acontrer56...> wrote:
>
> Questions about the face pattern have been posted on the Advanced Bird
> I.D. page on Facebook. I’m not going to copy and paste the comments but
> those who are interested should check it out.
>
>
> Alan Contreras
> <acontrer56...>
> Eugene, Oregon
>
> www.alanlcontreras.com
>
>
> On Dec 23, 2018, at 8:55 AM, Jeff Gilligan <jeffgilligan10...>
> wrote:
>
> If the published sources are correct, and the identification criteria as
> reported on chat sites by “experts” who live within the range of
> Intermediate Egret are correct in their comments, this is an Intermediate
> Egret.
>
> Unless the identification criteria is shown to be inaccurate, I will refer
> to the bird as an Intermediate Egret.
>
> Thank you for the additional photos. They are of plenty good enough
> quality to see the crucial identification factors.
>
>
> Jeff Gilligan
>
>
>
> On Dec 23, 2018, at 9:34 AM, Sally Hill <1sallyhill.9...> wrote:
>
> I overlooked two photos that have the next more extended.
> Here is link. https://ebird.org/view/checklist/S50848667
>
> Sally Hill
> Eugene Oregon
>
>
>
>

 
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