Greater Scaup
Aythya marila

Lake Ashurst
Coconino County, AZ
26 November 2005

This male Aythya duck was seen in the company of six or seven female Lesser Scaup and one male Lesser Scaup (among many others ducks) at Lake Ashurst, southeast of Flagstaff, Arizona. It was readily picked out by its larger size and larger bill. I felt on the basis of body size, bill size, and head shape over the 15 minutes we watched this bird that it was a Greater Scaup. One of the other two observers was skeptical, in part because he knew of no other records of Greater Scaup in the area of this lake, despite its being birded regularly by accomplished birders. The third observer, my wife Christine, was not completely convinced. She noted that the bill's nail (which I did not get a good look at) appeared broad, but to her the head shape was not consistently convincing for Greater Scaup, though she agreed that it stood out size-wise. The bird never spread its wings and so the wing-stripe was not observed.

I tried to photograph the bird, but was not successful in getting any good images, as you can see. However, the images I did obtain do show some of the features that I noted in the field.


The head shape in the photo here looks flat-topped with the high point in front of the eye.

Here the bird is shown next to a female Lesser Scaup. Note the striking size difference, and also the difference in head shape.

The same bird now swimming next to a Northern Pintail. The head shape again is like Greater Scaup, and the sizeable bill is also apparent.

One photo shows the head face-on. I'm not sure how to interpret this silhouette of the head. The bill, though, looks broad. Unfortunately it is hard to tell if the nail really is broad or if instead it's just that the photo is fuzzy.

Another photo, which might show a wide nail. The erect posture makes it harder for me to associate head shape with specific identity.

One more shot of the swimming bird that evidences a Greater-like head.

My conclusion is that this bird is indeed a Greater Scaup.

This page was last updated on 1 December 2005.
Contact Geoff Williamson with any comments, updates or suggestions.