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Although
the Wilson's Phalarope, Red Phalarope, and Red-necked Phalarope are
all in the same family as shore-hugging sandpipers, they are so unusual
that they have sometimes been considered a separate family.
All three species of phalarope forage while swimming, sometimes whirling
in a circle to create a vortex that brings small invertebrates to the
surface for easier capture. Wilson's Phalarope also relies on the standard
sandpiper feeding behavior -- probing through the mud. But its probing
is erratic and energetic in comparison to sandpipers.To catch prey,
a Wilson's Phalarope will wade rapidly with its bill open in the water.
It may also capture flying insects.
The phalarope genus name, Phalaropus, means "coot-footed" and
was inspired by the phalarope's feet which are adapted for swimming.
Two of the phalarope species winter at sea and have semipalmate (partially
webbed) feet with lobed toes, while the more terrestrial Wilson's Phalarope
has flanged toes.
But what really sets phalaropes apart is the reversal of gender roles
from the typical avian pattern. Before the males show up at the breeding
grounds each spring, female Wilson's Phalaropes arrive at shallow freshwater
marshes and wet meadows from southern Yukon Territory southward to central
Nevada and eastward to the Great Lakes. Aggressive females compete with
courtship displays during which they stretch out their necks and puff
their feathers. Once mated, they defend a small area around their males.
Females lay eggs in shallow depressions that they usually scrape within
100 yards of the shoreline. The males complete the nest lining and a
concealing canopy of grasses after the eggs are laid. Then the males
settle into caring for the nestlings until they fledge.
As soon as the breeding season ends in July, the legs of adults change
color from brownish-black to yellow. Females leave the breeding territories
first, from early June to early July, followed by the males and, lastly,
immature birds. Starting in August, adults molt into a drab winter plumage.
The last migrants linger until as late as October.
The main migration passes west of the Mississippi River but a smaller
number also migrates along the Atlantic Coast. Most Wilson's Phalaropes
spend the winter in Bolivia, Chile, and the Argentina highlands along
salty and alkaline lakes.
Description:
Wilson's Phalarope has a short white supercilium or eyebrow stripe.
Its underparts are white and its long thin bill is black. Males are
about 25 percent smaller than females.
During the breeding season, adults have a black line through the eye
below the supercilium that extends down the side of the neck, flaring
at the shoulder and blending with chestnut coloring toward the front
of the neck.
Females in
breeding plumage are pale gray on the crown, back, wings, and tail.
The appearance of males varies during this time. Some individuals are
nearly as bright as a female but with darker crowns and more mottled
backs. Others are dull-looking with a gray and white coat that is reminiscent
of the winter plumage.
Nonbreeding birds have olive to yellow legs and plain gray plumage above.
The stripe through the eye is still visible as a gray line below the
white supercilium.
Recording
Credit:
The recording of the Wilson's Phalarope was made by Randolph Scott Little.
Recordings of the Wilson's Phalarope may be found on our
Peterson Field Guide Series Eastern/Central Bird Songs CD
available at our online Cornell
Lab Birding Shop.
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