Greater or Lesser Yellowlegs?

These commonly seen wading birds are very similar in appearance. As a result, it can present an identification problem in the field. This short guide is intended to make the task easier and with experience it should become accurate and fairly easy.

General Appearance

Both species are long legged waders with bright yellow legs. In addition they show black and white checkering on their backs with a mostly white belly. The neck and head are finely streaked. During the breeding season the checkering and streaking are bold and dark. Somewhat more brownish in the winter. The flanks also show some amount of streaking, more so in the breeding season. Both species have a long, mostly black beak and a prominent white eye ring.

Size Differences

The Greater or Lesser Yellowlegs differ greatly in size. The Greater being almost twice the mass and 75% longer from head to tail. Although this is very evident when the two species are together, when solo it can be less clear.

So, is it Greater or Lesser Yellowlegs?

The first thing that I see in a Yellowlegs is the general look. The Greater, being a larger and heavier bird with the Lesser appearing more “dainty”‘ Note below the general look of a heavier bodied, more robust bird in the Greater Yellowlegs. The head seems proportionally larger as well as the breast and belly. The long legs are also sturdier in the Greater Yellowlegs.

The most telling feature for me is the size and structure of the beak. The Greater Yellowlegs sports a beak that is at least 1.5x longer than the head, measured from back to front. The beak on the Lesser Yellowlegs is only just longer. In addition many Greater Yellowlegs show a slight upturn of the beak. The Lesser’s beak is straight and generally thinner. Although the Greater above does not exhibit much beak upturn, the other differences are easily seen. The next image shows a Greater with a slight upturn on the beak.

The Greater Yellowlegs tends to be more heavily barred along the flanks than the Lesser, especially in breeding plumage.

When seen in profile, the wing tips of the Lesser Yellowlegs extend past the tip of the tail. The wing tips of the Greater Yellowlegs extend about to the tip of the tail. This can be seen in the photos below.

Although not always reliable, the Greater Yellowlegs tends to show more white spotting on the secondary feathers in flight as above.

Vocalizations

Lesser Yellowlegs has a short quieter call usually only repeated 2-3 times while the Greater has a loud sharp call repeated 4 or 5 times. I will try to add some recordings of each species at some point.

Behavior

The Greater Yellowlegs tend to be a more active feeder than the Lesser Yellowlegs.

Direct Comparison of Lesser and Greater Yellowlegs

The most foolproof method to distinguish these two species is to see them together! However this is not always possible. If you do get the chance, take the time to carefully study the field marks. Once you have seen them together the differences become more readily apparent. With experience you can confidently distinguish these two species in the field.