scaup again

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Comments:
: Here's a radical reassessment. Perhaps like others, my first assumption was that the upper photo pictures a pair of the same species. After another look, I'm not so sure this is the case. : Having no appreciable experience with eclipse scaup, I was ignoring plumage and concentrating more on shape, particularly of the male bird in this photo. I am somewhat swayed by arguments for the female bird being a Greater, particularly the pale crescent behind the eye, the very high peaked forehead, and the apparently pronounced nail. : However, I am unconvinced that the male bird in the upper photo also has to be a Greater. The jizz of this bird initially struck me as a Lesser, and after looking again, that feeling seems to be reinforced by a direct comparison with the female. Note that while the male seems equally large-billed, the nail seems less pronounced. Also, the forehead does not appear nearly as high as on the female, the total bulk of the head seems less, and the body seems somewhat flatter and shorter. In particular, carefully compare the necks of these two birds. The male's neck seems quite thin and short, while the female's neck seems noticeably thicker, and longer even though it is not extended while the male's is. Can females look this much larger than males? As for the bill length, I would question if there might not be enough range of size where a male Lesser might not appear to overlap with female Greater(?) Male Lessers, at least, sometimes seem proportionatly large-billed to me, and hard to tell from Greater's based on that characteristic. I certainly could be wrong, but I have a very strong impression that there is nothing apparent about the upper male that is outside the range of appearance of Lesser, and the overall build and bulk seems quite slight for a Greater. : I may also be wrong about this, but I am so far unimpressed with head shape, position of crown peak, or eye position as reliable marks by themselves, at least in photos. I have seen Greaters compress their heads so that the crown peak is well behind the eye, and I have also seen Lessers momentarily flatten their crowns so that the crown peak is confusingly in front of the eye. When Lessers flatten their heads the eye can also be quite close to the top of the crown, so I'm not sure of the value of that mark in photos. The bill/forehead angle also seems somewhat posture-dependant to me. In fact, the upper and lower females seem to have a similar angle to me. : As stated, I don't have the experience to be certain about any of these individuals. But I strongly suspect that this is another situation where some of the marks being mentioned, while likely reliable in the field for individuals studied for any length of time, may be quite misleading in photos due to the posture and angle of view the bird is captured in. I think this quiz isn't necessarily as straight forward as it seems at first impression (happy, Joe?) : Cheers, : Phil

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