Date: 3/30/21 2:40 pm
From: David Bailey <davidcbaileyoregon...>
Subject: [obol] Re: Nailing Scaup Identification
Thomas,

Based on over head shape and slightness of the ducks, I would call all the
scaup in your two photos (IMG_9916 & IMG_9930) Lesser Scaups. The
iridescent sheen of purple more anterior and greenish more posterior on the
head I have seen often. The peak at the top of the head is similar in all
the ducks in your photos and what I first look for to distinguish them from
Greaters that have larger and more rounded heads. The black nail on Greater
Scaup would be wider on the dorsal portion of the bill, not just in the
middle of the bil with a spreading black line along the edge.

This link I just googled has some front-view photos of Greater and Lesser
Scaup that well-illustrate the differences in the black bill nail between
Greater and Lesser Scaup. It contains additional information in
identification of the two species.

https://www.birdzilla.com/bird-identification/id-skill-development/bird-families/waterfowl-identification/duck-identification/identification-of-diving-ducks/comparison-of-greater-and-lesser-scaup.html

Thanks,

David C. Bailey
Seaside, Oregon

On Tue, Mar 30, 2021, 11:18 Thomas Gilg <tom...> wrote:

> Thanks for the discussion!
>
>
>
> Everything I’ve read says “purplish head sheen” is authoritative for
> Lesser, but I see split opinion on “greenish head sheen” being
> authoritative for Greater, with some saying greenish can occur on Lessers
> too. Thoughts?
>
>
>
> I’m still trying to get the gestalt of head shape + lip stick + head sheen
> + flank cleanness solidified in my mind.
>
>
>
> Attached are 1/17/2012 picture from inland Brownville where the right two
> individuals had good green sheen (see IMG_9916), but I opted not to call
> them Greaters.
>
>
>
> --tgb
>

 
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