[Mnbird] Greater or Lesser Scaup?

[Steve Weston]

some of the other field marks that you can look for besides head shape.
The GRSC has a brighter white side, whereas the LESC has a grayer side. I
have found this is a good, but subtle difference that is not always
evident. But, when you can see the difference, they are very easy to
separate.
The GRSC has a broader head and bill and a more obvious black nail on
the end of the bill. That is evident when you get a straight on shot.
Yes, when you can see the color of the head, the male LESC is purple, but
sometimes shows some green. And, the GRSC has a green head.

And, yes this is a Greater. You can see all three of these lesser known
field marks.

Note: This is not an easy ID. Probably 20 years ago a friend and well
respected birder ID'd 2 LESC and 1 GRSC (immature male) in February. The
GRSC was quite unexpected. I reported the trio. Repeatedly some of the best
known names in the area went down and reported 3 LESC's and disputed the
GRSC ID. I went down several times to confirm my ID, which ran counter to
the consensus that was forming. Luckily the birds hung around for more than
a month and the Greater molted into breeding plumage and the ID became
indisputable. The Sibley field guide is really good for separating the two
scaup.

Steve Weston
On Quigley Lake in Eagan, MN
sweston2g at gmail.com


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On Sat, Apr 1, 2023 at 9:13 PM Paul Lender via Mnbird <
mnbird at lists.mnbird.net> wrote:

> Hi Folks
>
> Here are two shots of the same bird at Como Lake, St. Paul, at about
> 5:40pm tonight (1 April 2023) in bright sun.  All the other male scaup that
> I can see had purplish iridescence when you could see it at all.  The angle
> on the head isn't great -- sorry about that.  Without a good shot of the
> head in profile, is the green iridescence definitive for Greater?
>
> Thanks in advance...
> [image: scaup_l_or_g.jpg]
> -- Paul Lender, St. Paul MN
> ======================================
> Paul Lender
> University of Minnesota Dept. of Orthopedic Surgery
> 2450 Riverside Ave. South, Suite R200
> Minneapolis  MN  55454
>
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>
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