Santa Barbara Island, the smallest of the Channel Islands off the Santa Barbara coast, has been closed until the end of May to protect the mating habits of the endangered California brown pelican.

The island, which lies within the Channel Islands National Park, was closed to the public on Feb. 10 because the park’s 300,000 annual visitors could disturb the birds during their breeding season. The pelicans, which are protected by federal law, are currently nesting close to the trail that serves as the only means by which the public can access the island.

Yvonne Menard, chief of interpretation for the Channel Islands National Park, said that since the birds usually build a large nest on the ground that will hold a single egg, human interference can scare the birds and jeopardize the survival of their offspring.

“Island pelicans are highly sensitive to any disturbance, and are known to abandon their nests for the entire season if disturbed,” Menard said.

She said there are several large breeding areas along the California coast where the pelicans are nesting.

“The Channel Islands support two of the three primary pelican breeding colonies on the West Coast of North America,” Menard said.

Menard said the birds have an eccentric breeding pattern, which results in a mating season that lasts from January to October.

“They are asynchronous nesters, meaning that individuals do not all start nesting at the same time,” Menard said.

The California brown pelican population on Santa Barbara Island ranges between 400-700 nests each year, Menard said, but the isolation of the Channel Islands is crucial to their reproductive success.

“The main cause of the decline, we think, resulted from high levels of the pesticide DDT in the food chain which resulted in [brittle] eggshells [being easily] crushed in the nests,” Menard said.