Greater Yellowlegs, Tringa melanoleuca

8/8/04, Coyote Creek Shorebird Pond, Milpitas
Greater Yellowlegs are distinguishable from the similar but smaller Lesser Yellowlegs by size when both seen together, as shown in two pictures on the Lesser Yellowlegs page. When either species is seen alone, the best distinguishing mark is bill size and shape; the Lesser's bill is typically about equal to the distance from the base of the bill to the nape, while the Greater's bill is half again as long. The Greater's bill is thicker at the base, more varied in color, and typically slightly upturned, where Lesser's is straight and mostly dark.

The two birds above and below are Fall migrant adults still mostly in breeding plumage, which is characterized by a mixture of black and brown feathers on the back, and heavy black barring on the flanks. 

Greater Yellowlegs, breeding plumage, 7/8/04, Palo Alto Baylands

Greater Yellowlegs, breeding plumage, 4/14/08, Boddeker Road, Galveston, TX
The birds above and below are seen mostly molted to breeding plumage in Spring, during or just before their migration to their northern nesting grounds.

Greater Yellowlegs, breeding plumage, 4/9/05, Shoreline Park, Mountain View

Greater Yellowlegs, non-breeding plumage, 3/16/08, Palo Alto Baylands
The adult non-breeding plumage, shown above and in the two following pictures, has mostly white underparts, and nearly solid gray-brown feathers over the upperparts, with alternating dark and light marks on their margins.

Greater Yellowlegs, non-breeding plumage, 12/3/07, Palo Alto Baylands

Greater Yellowlegs, non-breeding plumage, 12/3/07, Palo Alto Baylands
An adult in non-breeding plumage, feeding on a prey item.

Greater Yellowlegs, first winter, 12/4/04, Shoreline Lake, Mountain View
First-winter Greater Yellowlegs, above and below, have adult non-breeding feathers on the back, which grow in from the front backwards. The juvenal tertials, darker and with stronger white notches than the corresponding feathers on adults, do not molt, but are retained through the winter. Juvenal plumage also typically includes striping on the breast that ends in a fairly neat horizontal division between dark and light.

Greater Yellowlegs, juvenile molting to first winter, 10/14/10, Pillar Point, San Mateo Co
This first- year bird, in October, has molted in only the top half of the back with adult non-breeding feathers, retaining more of the juvenal black-and-white spotted and notched plumage than the December first-winter bird further above.

Greater Yellowlegs, flying, 7/31/10, Palo Alto Baylands