Arkansas scaups

[millipede]

I thought I just had a group of ring-necked ducks but as I got closer... scaup... At first I thought lesser, but I didn't focus while in the field as I was on something of a field trip and, well I was WAY behind everyone. HA.

The head appears greenish in every pic I have, which would lean greater. I feel the head shape, and bill width could support greater. And the female that is in some photos, the nail on the bill is WIDE... suggesting greater. But, this male...  that nail is pretty narrow. I'm still leaning greater though for the other reasons but would love some feedback.

[IKLland]

Tricky bird but head shape says greater 

[millipede]

Any second opinions? (I guess since I had the first opinion, any 3rd opinions?)
Haven't uploaded that checklist to eBird yet.

[Caley Thomas 2.0]

Leaning lesser on male (head shape somewhat compromised due to apparent active foraging though still appears to be crowning too far back on the head for Greater) and a slash for me on the female. Please take with a grain of salt here. Maybe both as a slash in fact…

[millipede]

This is one of the birds where I wonder if they do DNA testing and such to show enough distinction for them to be two completely separate species.   🤔

It's bad enough when I could go either way because photos aren't good... but when photos are good and you can still go either way?
I have a few other photos of both birds. These were just good enough, or I thought good enough to get answers with. ha. 
I have about a dozen photos of that male with at least some obvious green sheen to it.
And the female, I'll have to study some more, and maybe I'm mistaken about what is considered the nail, or how to judge it. The black on the tip of the female's bill seems to be as wide as the bill itself, but, that might not all be the "nail" but, just black? Does that make sense.

Unless I see a convincing argument, I likely will put them both in as a /

[Caley Thomas 2.0]

@DLecy@Aidan B

Any thoughts here?  I'd hate to be the sole poo-pooer on Greater....

[MichaelLong]

Lesser for me, head sheen color is not a reliable field mark and the water droplets indicate that the male has recently dove, making the head shape invalid. Nail shape says Lesser to me and the females head shape looks Lesser to me.

[Aidan B]

I guess I'm going against the last couple replies, but I actually feel quite strongly that the male scaup is a Greater. In my opinion, the nail on the bird is within the acceptable range for Greater. Also, while head sheen isn't always reliable, it is suggestive of Greater. In addition, the flank and the side of breast form an extensive, plain-white rectangular body. In a Lesser Scaup this area is more vermiculated and as such appears duller. 

[RobinHood]

9 hours ago, Aidan B said:

In addition, the flank and the side of breast form an extensive, plain-white rectangular body. In a Lesser Scaup this area is more vermiculated and as such appears duller.

I agree with the approach but I think the white (especially in the first photo) is overexposed. In the last photo you can see the pattern in the front section of the flanks. In the same photo you can also see the coarse barring on the upperparts which is more suitable for Lesser (not 100% reliable but more so than head colour).

I think these are classic tweeners with arguments for both sides. If I had to I would probably go Lesser because of the long vertical section at the back of both heads, but that is shaky.

[Charlie Spencer]

Greater / Lesser and move on to the turkey dinner.