Hi Tori and all,
Yes, the impression you are getting is correct and reliable, but I think
it is a composite of multiple features that differ between the two species.
The bill/forehead angle (where they meet), can be somewhat variable among
individuals and depending on if their feathers are matted down because they
are diving, etc. However, the appearance that the head is "taller" on
Lesser is a "real" appearance. I think it is due to at least two things.
One is that the relative (proportional) distance between the top of the
head and the eye is smaller on the Greater Scaup and larger on the Lesser
Scaup, which makes the Lesser Scaup head look "taller." The other thing is
that the top of the head on the Greater Scaup often slopes level or
downward toward to back of the head, again making the top of the head not
look so tall, whereas on the Lesser Scaup, the top of the head is level or
peaks near the rear. And, one of the most often reliable marks is that on
the Lesser Scaup, the rear of the crown of the head has a very slight to
obvious peak or notch, whereas the Greater Scaup usually has a very
smoothly downward curving back of the head at this location.
The other thing that is usually visible is just the size and thickness of
the head and neck. Look at many photos of each and you will see this
tendency. The Greater really is "greater" in this way.
There is a nice comparison photo of a pair of each from last year's
Reedsport CBC here:
http://umpquabirds.blogspot.com/2016/01/first-reedsport-christmas-bird-count.html
[Page/scroll down to find the photo and click to enlarge.]
And a bunch more here if you want to compare some more...
https://ebird.org/ebird/view/checklist?subID=S26602250
Matt
On Sat, Jan 14, 2017 at 10:14 AM, Tori Morgan <toripony@xxxxxxxxxxxx> wrote:
On the lesser I see a slightly steeper forehead where it meets the bill,
sort of a notch effect, whereas the forehead slope continues at the same
angle as the bill on the greater. To me this gives the lesser's head a
slightly taller, slimmer appearance. Is this a correct and reliable ID
characteristic?
Tori Morgan
Cottage Grove
On 1/13/2017 9:59 PM, Matthew G Hunter wrote:
Hi Folks,
Today I went to get my car looked at, and it was so ... uh, ...
not-rainy that I just had to LOOK AROUND a bit to see what was about....
At Stewart Park Wildlife Ponds there was a female GREATER SCAUP. We don't
see them very much here in the valleys, and I got a couple photos of a
female GREATER and LESSER scaup in the same photo, so thought I would share
for those of you interested in practicing the ID of these species.
https://www.flickr.com/photos/matthewghunter/31454708574/in/
dateposted-public/
https://www.flickr.com/photos/matthewghunter/31486004043/in/
dateposted-public/
Of course you could go to the ponds and try it out in person too!!!!!
Enjoy,
Matt Hunter
Melrose
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