Passing Through: Phalarope

Wilson’s Phalarope (Phalaropus tricolor)

Thanks to the sharp eyes of Jutta Burger, who knows her birds as well as her plants, I caught a few images of this Wilson’s Phalarope (Phalaropus tricolor) in the water just off the northeast corner of the park, where the seasonal Burrowing Owl refuge lies. The Phalaropes — I saw two of them — took wing when a half-dozen juvenile gulls settled in the water very nearby.

These Phalaropes are late-summer migrants coming from the northern states and Canada on their way to South America. Large flocks of them stop at salty lakes such as Mono Lake to feast on the tiny shrimp and insects that abound there. This pair obviously flew to a different drummer than the big flock. They moved fast, busily pecking at floating things invisible to the human eye. On shallow salt lakes they have perfected the trick of teaming up to paddle in a circle, creating a whirlpool that brings up edibles from the bottom.

The Cornell Bird Lab website has these “Cool Facts:”

Wilson’s Phalaropes are one of only two species of shorebirds that molt at resting sites on the migration pathway, rather than on the breeding grounds before leaving or on the wintering grounds.

While stopping over to molt on salty lakes in the West, Wilson’s Phalaropes usually eat so much that they double their body weight. Sometimes they get so fat that they cannot even fly, allowing researchers to catch them by hand.

Wilson’s Phalaropes almost always lay a clutch of exactly four eggs.

Unlike most birds where the female has the predominant role in caring for young, female phalaropes desert their mates once they’ve laid eggs. While the male raises the young by himself, the female looks for other males to mate with. This unusual mating system is called polyandry, and it’s reflected in the way the two sexes look, with the females more brightly colored than the males.

Jutta’s photo also captures the lovely abstract pattern on the water’s surface surrounding the bird:

Wilson’s Phalarope. Photo by Jutta Burger

Links: Wikipedia Cornell Audubon

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