Identifying Wilson’s Phalarope

The phalaropes are such unusual shorebirds — with their swimming and spinning habits, and with females much more brightly colored than males — that in the past, they were often considered to make up a family of their own. More recent studies have firmly established their place among the sandpiper family. But from the birder’s standpoint, they’re still unique.

Two of the species, Red Phalarope and Red-necked Phalarope, nest on high Arctic tundra and winter out at sea. The third species, Wilson’s Phalarope, nests in marshes in the interior of North America and winters on lakes in South America. It’s the most distinctive member of a unique group.

The breeding distribution of Wilson’s Phalarope is mostly west of the Mississippi, from the northern Great Plains to the western edge of the Great Basin. Much of this region is arid country where marshes may vary with local rainfall, and the phalaropes seem prone to change their breeding sites from year to year. Perhaps as a result, there are many records of the species showing up and nesting far to the east of the main range. During the warmer months, it might be seen almost anywhere in North America.

The “fall” migration of Wilson’s Phalarope begins remarkably early. Females may finish laying eggs for their mates and depart from the breeding territory before the middle of June. Adult males, after finishing or failing at their chick-rearing duties, can be on the move by early July; shortly thereafter, freshly fledged juveniles start to wander. In late summer, tens of thousands of individuals gather on saline lakes in the western U.S. and Canada — for example, at Great Salt Lake, Utah, and Mono Lake, California — before making an early fall flight, apparently nonstop, to western South America.

The Wilson’s is usually not hard to distinguish from the other two phalaropes. It’s a bit larger with a more elongated body shape and usually a noticeably longer bill. It also shows distinct differences in color pattern in every plumage. Well-marked breeding birds are so different as to preclude any chance of confusion. Those in pale gray winter plumage are more similar, but differences in head pattern are diagnostic. In flight at any season, they’re easily separated: Wilson’s has a whitish rump and tail and no wing stripe, while the other two show prominent white wing stripes and a dark center to the tail.

Far more than the other two phalaropes, however, Wilson’s might be confused with other species of sandpipers. This is partly because it tends to do more walking and wading than the other two. Often it draws attention to itself with active behavior, dashing about the flats. In winter plumage, gray with yellowish legs, it might suggest something like a Lesser Yellowlegs. The juvenile, more brownish overall, could suggest a juvenile Stilt Sandpiper. In every case, close attention to the bird’s shape should make its identity clear. 

As expected on adult phalaropes in breeding plumage, the pattern of the adult male Wilson’s is like a muted version of the female’s bright colors. Typically, the overall effect is darker, as on this bird, but some males in late spring and summer are much paler. Details of face pattern, along with the lack of strong pale stripes on the back and the wash of cinnamon across the front of the neck, should help to rule out the other two phalarope species. Note the black legs on this bird, typical of the breeding season. On adults in winter, the legs vary from greenish to dull yellow, while juveniles have bright yellow legs at first, fading to pale yellow.

Juvenile Wilson’s Phalaropes, with their strong tinges of brown, might be mistaken for other species of sandpipers — especially when they’re walking on mudflats or wading rather than swimming. In full juvenile plumage, all the large feathers of the wings and upperparts have dark centers and sharply contrasting buff edges. Only a few sandpipers have similar patterns, and none of those match this bird’s shape. With its bright yellow legs, the phalarope might suggest a short-legged version of Lesser Yellowlegs, but the latter species has fine spots along the edges of its upperparts feathers, not broad buff edges. Shortly after these young phalaropes become independent, the scapulars and then the coverts begin to be replaced with plain gray feathers.

In full winter plumage, Wilson’s Phalaropes are plain and pale overall, patterned in gray and white. The other two phalarope species may be plain gray on the back (Red Phalarope) or gray with white stripes (Red-necked Phalarope), but they always have a blackish patch behind the eye and a white forehead. On Wilson’s Phalarope in winter, the stripe behind the eye is pale gray, and the gray of the crown often extends onto the forehead. Wilson’s usually has a distinctly longer bill than the other two, but this varies. The individual in this photo is a young bird that hasn’t fully molted into full winter plumage, still showing some dark-centered, buff-edged feathers on the tertials, greater coverts, and rear scapulars.

Female Wilson’s Phalaropes in the breeding season, with their sharp patterns and rich colors, mostly look alike, but there’s a surprising amount of variation in the males. Some merely look like darker and duller versions of the females, as seen in a photo on the preceding page, but others are much paler, like the one in this photo. Although the frosty look of this individual might suggest that it’s still partly in winter plumage, a closer look shows that some of its pale gray feathers are relatively fresh. Such dull individuals may be second-year males. For ID to species, note the elongated overall shape and the distribution of darker gray and pale cinnamon on the neck.