LOS ANGELES -- Thirty minutes after setting sail for the Channel Islands National Park, Ana Sofia Guerra spotted a creamy white sea gull soaring majestically against the slate gray sky.
The other passengers on the 64-foot catamaran were captivated by a pod of dolphins leaping playfully from the water, but Guerra kept her eyes trained on the solitary gull.
The ecologist pointed a large camera skyward and snapped a picture of the seabird gliding on the strong ocean breeze. Then a smile spread across her face.
"It's probably heading back from a trip to McDonald's," she said.
For the last few years, Guerra has been studying the eating habits of western gulls that nest on Anacapa and Santa Barbara islands in the Channel Islands archipelago.
She's tracked sea gulls on ventures from their pristine island home to an In-N-Out in El Segundo, a catering kitchen in Compton and the Roadium Open Air Market in Torrance.
On one trip, a bird she monitored flew to a row of Vietnamese restaurants in Anaheim, then visited a bakery a few blocks away for dessert.
In their natural habitat, gulls primarily eat squid, anchovies, crabs, barnacles and other marine life. But when it comes to people food, they are willing to try just about anything.
"There was a gull on Santa Barbara Island that vomited an entire corn dog with a stick," Guerra said.
Usually it's humans who are responsible for polluting natural ecosystems. But on Anacapa and Santa Barbara islands, gulls appear to be the ones spoiling the wild habitat with processed food and puked-up trash.