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Phalaropes descend on Rodeo Lagoon

by on August 07, 2012


Rodeo Lagoon in the Marin Headlands is the place to go right now to watch a rare migratory shorebird that enacts a fascinating swap in gender roles.

In late July into the first half of August, red-necked phalaropes descend on the eastern end of the lagoon to tank up on tiny crustaceans and insects. The 8-inch bird with a striking black cap and mask has one of the longest North American migratory journeys of any bird, breeding in the high Arctic tundra and wintering off the western coast of South America.

Safe to say, they need Rodeo Lagoon as a pit stop.

What gets ecologists all worked up is the bird’s highly unusual gender behaviors. The female is bigger and more colorful than the male. It is she who mates multiple times. And the male is the one to raise the young.

Ornithologists believe that a long and arduous migration requires the females to pare down their reproductive effort. Egg-laying is about all the stress she can bear, so the males pick up the rest of the hard work. She then has time to spend with other males, feeding and prepping for her long trip.

Get out to Rodeo Lagoon and observe some of that!


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Nicoll on August 11th, 2012 at 12:09 pm

I spotted six pharalopes almost immediately as they were approaching the far west side of the lagoon near a beachy outcrop into the lagoon. I was watching intently, hoping they would come into some exposed marsh area to feed. I had a good vantage as they cautiously began to forage. A bobcat pounced from the complete camouflage of the tall marsh reeds and snatched one of them then turned and slowly melted back into his hiding place. It was thrilling. But there was one less of the rare birds. I spotted 2 large groups of pharalopes throughout the day – 16 and 19. I also saw 25 other bird species (at least!), 2 grey foxes and some happy humans. Thanks so much for the information on this lovely spot that I had neglected to visit!

Dan Rademacher on August 11th, 2012 at 6:15 pm

Wow! A bobcat catching a phalarope. That’s quite a sighting!

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