Phalaropes descend on Rodeo Lagoon

August 7, 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!


About the Author

Alison Hawkes was a Bay Nature editor from 2011-2017. Before Bay Nature she worked in journalism for more than a decade as a former newspaper reporter turned radio producer turned web editor with each rendition bringing her closer to her dream of covering environmental issues. She co-founded Way Out West, a site dedicated to covering Bay Area environmental news.