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December 2011

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From:
Victor Fazio <[log in to unmask]>
Reply To:
Victor Fazio <[log in to unmask]>
Date:
Mon, 5 Dec 2011 14:32:55 -0800
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 I appreciate the recent discussion regarding the question of
small goose identification in Ohio. I share Bill's
reservations in general and have expressed my concern
in the pages of North American Birds with regard to the 
question of Cacklers. I believe I have been equally 
skeptical of reports of Ross's Goose over the years
with respect to publication within the ornithological record.

Bill has expressed concern over the identification of the 
putative Ross's Goose in Ashtabula. He correctly notes
Ohio has a history of hybrid white geese. However, I
must disagree with the notion that the Ashtabula bird
in any way exhibits hybrid characters.

If I read Bill's note correctly, it almost entirely boils down
to the presence of 'dark lips" which I take to be the 
presence of a grin patch, ostensibly a feature of a Snow
Goose, while also sporting the blue-gray patch of color at the
base of the bill, a feature of Ross's Goose.

This debate seems to come up every time someone gets
a photo close enough to see these features clearly. Any
further away and that grin patch would be subsumed in
the overall look. Similarly, so too are we presented with
a bill structure that some have wondered is not all that
stubby as we are told in field guides to expect. Again,
step away from such proximity and I submit the stubbier
one perceives this to be.

What if I were to tell you that the bill is perfectly normal
in every respect of shape, size, and color for Ross's Goose.

What if I were to tell you that the norm for a Ross's Goose 
is to exhibit a grin patch?

And what of the vertical feather edging where the bill meets the face
as opposed to a sharply concave appearance in a Snow Goose?

I imagine you would want to investigate those claims. I would
then ask that you examine any and all of the following
photographic guides by Stokes (2010), Floyd (2008), Brinkley
(2007), or Kaufman (2000). Even though the images are not
especially close-up, one can make out all of the features above,
including the grin patch to the extent exhibited by the bird
in Ashtabula. Better yet, take a look at the side-by-side
close-up of the two species given in Crossley (2011).

In a sampling of 40 images from the photo site Flickr,
I could only find 4 matching the lack of a grin patch depicted 
in Sibley for a Ross's Goose. Furthermore, Sibley's 
example of a hybrid illustrates a blending of characters as 
alluded to by Bill, not a mixed set. If I am 
to follow Sibley, I would expect to see a blending of the
bill color not the robust presentation of a Ross's Goose that 
we see in the Ashtabula.

Please examine your own google searches for more examples. Here
is a gallery of 18 images (limit set by Flickr) of close-ups of Ross's
Goose.

http://www.flickr.com/photos/victor_fazio-iii/galleries/72157628294948177/


And my own close-up of one individual from sw. OK ...
http://www.flickr.com/photos/victor_fazio-iii/sets/72157628295254011/with/3233648282/

[I see roughly 100 Ross's vs 10,000 Snows per annum in OK]

As to size ... this is another problematic presentation in the literature.

Yes, the most recent (6th ed.) of the National Geographic guide, as
one example, gives the length of both Ross's Goose and Mallard as 23 inches
which to many might sound as though they are the same size. Given that
every Ross's Goose I have seen paddle in front of a Mallard puts it in its
shadow, this warrants a closer look. Sourcing Cornell University's
"All About Birds" which in turn sources the NAB online accounts, I
find some variation ...

Mallard: 19.7 to 25.6 inches 
Ross's Goose: 22.4 to 25.2 inches

 ... not much of a difference, although stick a 25 inch Ross's next to a 20 inch 
Mallard
and I'm guessing you'd notice. But as pointed out by Mike Busam, it's really 
about
heft. In weight ...

Mallard: 1000 to 1300 g
Ross's Goose: 860 to 2040 g

So there are those pairings where they are comparable, and there are those
where a Ross's Goose may be as much as twice the size of a Mallard.

I do not want to blow things out of proportion. I am trying to counter
what I find to be some outdated misperceptions surrounding hybrid white
geese. They do exist, and Ohio has some of the best documented examples.
But I think we also need to take a moment to examine all of the record
and understand what I argue is natural variation. If I am wrong, and the
characters in the Ashtabula bird put forth as that of a hybrid holds true
in the eyes of those more expert than I, then about 90% of all the putative 
Ross's Goose photos I have seen depict hybrids, including all those
appearing within a decade's worth of photo guides.

cheers

Vic Fazio
PI: Black-capped Vireo Monitoring Project, Fort Sill M.R., OK
Oklahoma Bird Records Committee 
Regional Editor, OH-WV-PA, North American Birds
State Reviewer, OK & OH, Project eBird

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