Biologists seek answers to mysterious migratory bird

Aug 23 2013 - 11:49am


A Wilson's phalaropes shorebird feeds while in migration. (photo courtesy Judd Patterson/
A Wilson's phalaropes shorebird feeds while in migration. (photo courtesy Judd Patterson/

OGDEN -- All the trendiest Wilson's phalaropes spend summer at the Great Salt Lake, to partake of the bountiful brine fly feast. Then it's off to sunny Argentina, to spend that country's summer at a similar salt water buffet.

Biology graduate student Marcela Castellino of the National University of Cordoba has followed the same route this summer. The Argentine biologist and Weber State University Professor John Cavitt are both interested in solving the mystery of the half-million or so Wilson's phalaropes that arrive annually in Utah before heading on to Argentina's Lake Mar Chiquita.

"I grew up really close to that lake, and it is a beautiful place," said Castellino, 28. "I was always interested in nature, and the lake, almost as big as the Great Salt Lake, is one of the big reasons, because of all the things I was able to see."

Wilson's phalarope is a variety of shorebird that has a wingspan of about 17 inches, sports fringed feet and weighs a bit more than 2 ounces, with females weighing as much as 40 percent more than males.

Wilson's phalaropes are also known for their atypical mating habits.

"They are fairly unique in the bird world, because they are polyandrous," said Cavitt, a WSU zoology professor. "The females lay the eggs in the nest, and the male cares for them. The females will often have more than one mate. The females have the more bright, gaudy plumage because they are competing to attract the males. The females usually arrive here first, because the males are still up north, taking care of the nests."

The species tends to nest in Canada. The males and their young follow the females south, to salty lakes such as Mono Lake in California; Lake Abert in Oregon; or to our own Great Salt Lake. About a third of the species uses the Great Salt Lake.

Castellino said she was drawn to study the Wilson's phalarope because so little is known about the habits of the species.

"I am trying to find out the places they are using at the Great Salt Lake to rest during the day and at night," she said. "It's important to know the places they are using for different activities, like feeding and resting, so people can take care of the places. These are places to preserve."

If the areas used by the birds were to suffer extremely low water levels, pollution or other events causing the loss of food source, the species could be devastated.

"Knowing the areas they use would allow us to know more about the biology of the species," Castellino said. "It's important to the conservation of the species."

Castellino's international study is a partnership of Weber State and the National Audubon Society. It's primarily funded by Moab philanthropist Jennifer Speers.

Cavitt said Weber State hosts four or five students from Latin America each summer, offering help and guidance, if needed, with shorebird-related studies.

People outside the academic community often ask Cavitt why such studies are important.

"I struggle to answer, because I don't understand why people wouldn't care," Cavitt said, with a laughing. "But one reason is that birds are the canaries in the coal mine, so to speak. They are very sensitive to environmental changes and can indicate the health of the ecosystem.

"Another reason is we really need to consider these species as our responsibility. If you go to Argentina, people who live there consider the Wilson's phalarope their species as well. If we are doing something here to negatively impact the birds, it could drastically impact a species Argentinians view as their own. It's our responsibility to ensure these species thrive in this system."

The birds also consume large quantities of brine flies.

"The lake provides a huge surplus," Cavitt said. "We could presume any kind of impact we see on the birds would flow down to invertebrates as well."

Castellino said if she could get any message to locals, she would urge them to see what is all around.

"This is a really beautiful place with an amazing number of birds," she said. "It's such an important place. It's really important to take care of it, to pay attention. Spend a sunset at the lake, and a sunrise. Pay attention to the little things. When you know something, you want to take care of it. That is one way to help conservation."

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