Date: 9/12/17 11:16 pm
From: Matt Cahill <matt.c.cahill...>
Subject: [obol] Re: Malheur Narrows Egrets
Hi all,

I went back out to see the hegrets this afternoon, to watch them interact
and take a few more photographs. I expected to confirm my doubts about the
(potential) little blue, instead I walked away doubting the (potential)
cattle egret even more. Back home in Bend, I read this thread and some
additional resources and developed my own theory. Read on if you're still
enjoying this ID challenge as much as I am.

David Sibley has a very helpful article (I think) on differences between
snowy egrets and juvenile little blues, the only difficult heron ID in his
opinion. The article is here: http://www.sibleyguides.com/
2012/08/distinguishing-immature-white-little-blue-heron-from-snowy-egret

He writes extensively about how habit is a very useful ID trait. In short
summation, both of the mystery hegrets behave much more like little blues
than snowies (so I think). But more definitively, Sibley writes that little
blue heron "wingtips show small dark gray tips on outer
primaries...[and] are diagnostic". Both birds do show this trait in some of
my photos, one more extensively than the other. See the fourth photo from
yesterday's checklist (I added more from my SLR): http://ebird.org/ebird/
view/checklist/S39142883

Sibley continues that the "presence of black [on the legs] is diagnostic
for Snowy Egret, as is contrasting yellow feet." Both birds show nearly
identical leg and foot coloration: a complex pattern of yellow and black.
But definitely black. See today's checklist for a good comparison:
http://ebird.org/ebird/view/checklist/S39154699

These two traits are contradictory. Both birds have 'diagnostic' qualities
of both snowy egrets and little blues, with habit supporting LBH's. But to
further complicated it, the 'cattle egret' individual has a very yellow
bill which if looked at in isolation (along with the surrounding gape)
looks very much like a cattle egret, to me. Sibley writes that snowies have
a "bill usually darker [than LBHs] with blackish on culmen extending back
close to forehead". Sifting through Google Images, I can't find any photos
of LBH's or Snowies of any age having such a yellow bill as the 'cattle
egret' individual.

Interestingly, it is easy to find pictures of juvenile Cattle Egrets with
similar leg patterns as both of our individuals. Which leads me to a theory
I'll offer. Could it be that both of these birds are Cattle Egret x Little
Blue Heron hybrids? Such a hybrid could show the same leg and foot pattern,
wing pattern, and variety of bill shapes and colors as our friends at the
Narrows. Could it be even further that these two birds are nest mates? It
doesn't seem completely beyond logic that a little blue and a cattle egret,
both near the edge of their range and finding no appropriate mate instead
found each other. Then their offspring found an incredible bounty of dying
carp at the Narrows. I could be reading into it, but the birds seem to like
each other, in a sibling rivalry kind of way!

In short, I don't see how we can claim either bird is a pure Snowy Egret,
Little Blue Heron or Cattle Egret, at least not based on resources I've
found. A far-flung Asian species is exciting, but seems harder to stick
than a native hybrid. Putting the pieces together, this is the outcome I've
found. Would love other's thoughts.

Thanks for reading!

Matt Cahill

Bend

On Tue, Sep 12, 2017 at 11:12 PM, Matt Cahill <matt.c.cahill...>
wrote:

> Hi all,
>
> I went back out to see the hegrets this afternoon, to watch them interact
> and take a few more photographs. I expected to confirm my doubts about the
> (potential) little blue, instead I walked away doubting the (potential)
> cattle egret even more. Back home in Bend, I read this thread and some
> additional resources and developed my own theory. Read on if you're still
> enjoying this ID challenge as much as I am.
>
> David Sibley has a very helpful article (I think) on differences between
> snowy egrets and juvenile little blues, the only difficult heron ID in his
> opinion. The article is here: http://www.sibleyguides.com/
> 2012/08/distinguishing-immature-white-little-blue-heron-from-snowy-egret
>
> He writes extensively about how habit is a very useful ID trait. In short
> summation, both of the mystery hegrets behave much more like little blues
> than snowies (so I think). But more definitively, Sibley writes that little
> blue heron "wingtips show small dark gray tips on outer
> primaries...[and] are diagnostic". Both birds do show this trait in some of
> my photos, one more extensively than the other. See the fourth photo from
> yesterday's checklist (I added more from my SLR): http://ebird.org/ebird/
> view/checklist/S39142883
>
> Sibley continues that the "presence of black [on the legs] is diagnostic
> for Snowy Egret, as is contrasting yellow feet." Both birds show nearly
> identical leg and foot coloration: a complex pattern of yellow and black.
> But definitely black. See today's checklist for a good comparison:
> http://ebird.org/ebird/view/checklist/S39154699
>
> These two traits are contradictory. Both birds have 'diagnostic' qualities
> of both snowy egrets and little blues, with habit supporting LBH's. But to
> further complicated it, the 'cattle egret' individual has a very yellow
> bill which if looked at in isolation (along with the surrounding gape)
> looks very much like a cattle egret, to me. Sibley writes that snowies have
> a "bill usually darker [than LBHs] with blackish on culmen extending back
> close to forehead". Sifting through Google Images, I can't find any photos
> of LBH's or Snowies of any age having such a yellow bill as the 'cattle
> egret' individual.
>
> Interestingly, it is easy to find pictures of juvenile Cattle Egrets with
> similar leg patterns as both of our individuals. Which leads me to a theory
> I'll offer. Could it be that both of these birds are Cattle Egret x Little
> Blue Heron hybrids? Such a hybrid could show the same leg and foot pattern,
> wing pattern, and variety of bill shapes and colors as our friends at the
> Narrows. Could it be even further that these two birds are nest mates? It
> doesn't seem completely beyond logic that a little blue and a cattle egret,
> both near the edge of their range and finding no appropriate mate instead
> found each other. Then their offspring found an incredible bounty of dying
> carp at the Narrows. I could be reading into it, but the birds seem to like
> each other, in a sibling rivalry kind of way!
>
> In short, I don't see how we can claim either bird is a pure Snowy Egret,
> Little Blue Heron or Cattle Egret, at least not based on resources I've
> found. A far-flung Asian species is exciting, but seems harder to stick
> than a native hybrid. Putting the pieces together, this is the outcome I've
> found. Would love other's thoughts.
>
> Thanks for reading!
>
> Matt Cahill
>
> Bend
>
> On Tue, Sep 12, 2017 at 9:54 PM, Shawneen Finnegan <
> <shawneenfinnegan...> wrote:
>
>> It is in Rick Vetter’s notes:
>>
>> The white plumage appears almost identical on both, down to the mottled
>> gray smokey smudges on wings, primaries and secondaries just different
>> areas in some cases. Leg and foot color, very similar, a mottled yellow
>> green color but at times in different areas. Bill color is different,
>> yellow vs a bone pale flesh color with small black tip. Bill length
>> seems slightly longer on bird to right. And this bird appeared slightly
>> larger in body size. In the photo it was about 12 inches closer than bird
>> on left.
>>
>>
>> Shawneen
>>
>> On Sep 12, 2017, at 9:52 PM, Jeff Gilligan <jeffgilligan10...>
>> wrote:
>>
>> I haven’t seen dusky wing tips on the photos of the bird identified as a
>> Cattle Egret…
>>
>> Jeff
>>
>>
>>
>

 
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