Currently, I’m in the Intermediate camp. I agree with
Marnix about the neck length, the left hand photo in particular looks too
short-necked to be a Great. I think the length of the gape line also looks okay
for Intermediate. However see below for more on neck & gape length.
Another thing that suggests Intermediate is the rather
jowly appearance (ie rather baggy looking feathers on the upper throat), quite
noticeable in Roger’s 2 right hand photos, and in Geoffrey’s shots
of the Intermediate at Kellys. This feature doesn’t seem to crack a
mention in the field guides, but does in HANZAB, and can be quite noticeable in
the field when you have the 2 spp side-by-side. It is more pronounced on Cattle
Egrets and absent, or reduced, in Great Egret.
Egrets are fun though. I remembered an article on egret
identification by Graham Pizzey, (‘Egrets without regrets’
published in Wingspan Vol 7 No 2, June 1997), and have just dug it out. He
discusses id of the 2 species at considerable length. One interesting fact I
had forgotten is that some small female Great Egrets have head and neck
barely longer than body, so the 1.5 times rule isn’t necessarily fool
proof. He also notes flat-crowned appearance of Great cf more rounded head of
Intermediate, and comparatively shorter, slightly deeper bill of Intermediate.
There is also a brief mention of the ‘jowly’ appearance of
Intermediate, although, oddly, this doesn’t seem to have made it into his
field guides. All these differences are noted as subtle and most useful when
the two spp are seen together. On gape length – “the differences
between the two are in some cases so fine as to be chancy, but in most
instances the comparison works, particularly if bolstered by other positive
features”. ID of these birds is certainly not always straightforward!
Cheers
Steve
From: Geoffrey Dabb
[
Sent: Saturday, 17 May 2008 2:45 PM
To: 'COG'
Subject: RE: [canberrabirds] help with egret
I’ll reply more fully later. It would be helpful if
Roger could send his best possible enlargements of a profile head and
bill of all birds where the ID is in question -doesn’t matter if
they’re blurry.
In the meantime here are comparisons of 4 egrets from Kellys I
posted last November. Note the sharp triangular notch under the bill of
the 3 GEs on the left.
From: Marnix Zwankhuizen
[
Sent: Saturday, 17 May 2008 10:40 AM
To: COG
Subject: Re: [canberrabirds] help with egret
This bird
looks like an Intermediate Egret to me. It could be the same bird I saw over a
month ago at Yerrabi.
In the photos where it has it's neck stretched out fully the length of the
head/neck is still approx. the same as the length of it's body. In the Great
Egret it is usually c.1.5 times the length of it's body. Also the gape of it's
bill does not go all the way below it's eye and then beyond the end of it's eye
as mentioned in some guides.
But then I am happy to be proved wrong and haven't ever seen a juvenile Great
Egret.
Cheers
Marnix
On Fri, May 16, 2008 at 9:40 PM, Geoffrey
Dabb <> wrote:
My short vision
isn't what it used to be, but all those photos seem to be of a Great
Egret. I was there a few weeks ago when 2 G Egrets were there, and one
was markedly smaller than the other. I am going by the bill,
discounting the neck and posture which depends on the attitude of the bird at
the moment.
From: roger curnow [
Sent: Friday, 16 May 2008 8:43 PM
To: COG
Subject: [canberrabirds] help with egret
I have never used Flickr before, but hopefully at:
is a photo of either one or two egrets.
The photos were taken at Yerrabi pond a fortnight apart.
I thought they were all of the one bird,
and
based on the black legs, a Cattle Egret;
but following conversations with others, I begin to wonder.
Could someone who is confident in their egret classifying
abilities
tell me if they are both Cattle Egrets, both Intermediate Egrets or one of
each.
If there is a simple rule available could I know that..
