I picked greater yellowlegs for the Bird of the Day because it was the bird we spent the most time with. There was some debate about whether this bird was a lesser or a greater yellowlegs. When asked about this bird I gave my usual flip response that it was a medium yellowlegs. There is great value when a group of birders debate (in a nice way) the finer points of identification. It's wonderful to hear others' observations and opinions of a bird that is right in front of you. It can be quite illuminating and educational. The yellowlegs are a classic pair of birds which are very similar in appearance and thus difficult to distinguish. First off, this bird was in its winter or basic plumage which is more subdued than the breeding or alternate plumage. Overall, my first impression was this bird was more robust, sturdier than a lesser yellowlegs which has a dainty appearance. Greaters are also larger than lessers, but without a side-by-side comparison it can be hard to judge size. Especially after reviewing my photographs, you can see that this bird has a relatively long and slightly upturned beak. These are both characteristics of a greater yellowlegs. The beak also shows a two-tone coloration with a gray base and black tip which is exhibited by greaters in basic plumage. Lesser yellowlegs always show a completely black beak. In another photograph, it shows a plain and uniform underwing. Lesser yellowlegs have a little bit more "pattern" or differentiation in their underwing. So instead of deeming this bird a medium yellowlegs, we'll call it a greater.