The pursuit of bird watching is greatly enhanced by such look-alike species as the Greater Yellowlegs and the Lesser Yellowlegs. We look forward to the challenge they present each spring and fall as they migrate through Ontario.
When you see the two kinds of Yellowlegs together, there is usually no problem in separating the big, boisterous beauty from the smaller more sedate Lesser Yellowlegs. The long, bright yellow legs are shared, but the relatively longer, slightly upturned bill of the Greater, its resonant 3-syllabled whistle and its much larger size readily distinguish it from the Lesser. If no Lesser is present then look for a Killdeer – the Greater is much larger than a Killdeer while the Lesser is about the same size or smaller.
If you are in any doubt about which species of Yellowlegs you are looking at, it is probably the Lesser (as in these photos: Miles) They frequent the borders of marshes during migration in late spring, late summer and autumn, often in company with Greater Yellowlegs.
The whistle of the Lesser is less loud and is usually of two syllables, rather than the resonant 3-syllabled call of the excitable Greater Yellowlegs.
Dr. J. Murray Speirs