Posted by Phil Pickering (208.46.229.181) on December 18, 2001 at 12:09:14:
After taking the time to view several photos, I see that the bill size of the male in the upper photo IS probably too large/long for Lesser. Additionally, there is not enough of a size difference between the male and female in this photo to suspect that they aren't the same species, so pardon that nonsense.
It is clear to me, though, that the head shape, position of crown peak, eye position relative to the crown, and bill/forehead angle are all so closely tied to posture that it is dangerous to use them as marks for birds in photos, except for individuals that show extreme tendencies. I was able to find photos of (correctly identified) Lessers with a head shape and forehead angle similar to the upper male, and photos of Greaters with head shapes similar to the lower bird's. The proportional size/length of the bill seems to be a somewhat more reliable mark, although the difference is subtle, taking more experience than I have to judge consistently.
So, I have to waffle and agree with all that the upper birds are likely both Greaters based mainly on bill size and patterning on the female. The lower bird does have a somewhat short bill, and the bill/forehead angle is extreme for Greater, even accounting for changes due to posture. Will have to look again at this bird when I have more time.
Cheers,
Phil