The birds breed in the coastal salt marsh of Newport's Back Bay between March and October.
"It's unfortunate timing," said Richard Zembal, an endangered species coastal wetlands specialist who also is the natural resources director for the Orange County Water District. "It's the sheer mass of humanity that might cause problems, but it's not for me to say whether the marathon should or should not be called off. That's up to the city of Newport Beach and U.S. Fish and Wildlife Service."
Zembal said that, whatever the outcome, the issue might help bring to the forefront the importance of the light-footed clapper rail, which he's been studying for the last three decades. He said the Upper Bay accounts for 131 breeding pairs of a total 372 pairs that have been counted from Santa Barbara south to the California-Mexico border.
The bird, declared an endangered species in 1973, thrives in 19 different sorts of salt marshland, he said, adding that the next largest population is the Tijuana Marsh near Imperial Beach, just south of San Diego.
One of the marathon's organizers, former Assemblyman Scott Baugh, said it has already received permission from the California Department of Fish and Game and that he has the proper permit to stage the 2011 marathon.
He said he will wait and see what happens between the city of Newport Beach and Fish and Wildlife Service.
Baugh said he did not understand the confusion because Back Bay Drive, a small stretch through which the marathon will wind, is a public thoroughfare that's always filled with hikers, bikers and runners.
"Our primary interface is the Department of Fish and Game, which has given tentative approval for the race," Baugh said. "I'm aware that there are breeding seasons that go on at different times of years, but we engage in numerous mitigating measures to avoid disruption."
For example, Baugh said amplified sound is barred from the race along with water stations and portable toilets.
"The runners run on a public road," Baugh said. "Cars drive on it, motorcycles drive on it. Runners virtually run on it every day."
The only thing Baugh could think of that might be a potential problem is if paper cups get blown into the nesting grounds and need to be cleaned up after the race, causing crews to step on the nests.
"We've done this for two years," he said of the marathon course through the Back Bay. "This will be the third year.
In all, the race is six years old, he said.