A Test of Nerves Awaits Least Terns at Sanctuary

It doesn’t look like much--a stretch of sand, shells and scraggly, gray-green strands of beach primrose.

But these 7 1/2 acres just north of the Santa Ana River are a prime nesting ground for the California least tern, a gull-like bird that is on both state and federal endangered species lists.

For 15 years, this swath of beach has been a preserve for the least tern.

Lately, however, it looks more like a construction zone.

Along the bird sanctuary’s southern border, men driving bulldozers and cranes are laying mammoth tunnels of sewer pipe for the Sanitation Districts of Orange County.

On the beach just to the north, 40 workers in hard hats labor on an Orange County flood-control project, cutting a channel from nearby Talbert Marsh to the sea.

And on April 2--just south and east of the preserve, on the bridge over the Santa Ana River--the California Department of Transportation will start a two-year project to widen Pacific Coast Highway from four to six lanes.

In all, “the place looks like a battlefield,” one recent visitor said.

By agreement with the state Department of Fish and Game, all but the Caltrans work is scheduled to stop before the birds fly from Central America to their traditional nesting place in mid-April.

Still, some bird experts are worried that contractors are cutting the deadline awfully close. Work on the flood-control project is to end by April 1, but the sewer pipe replacement is not expected to be completed until April 13.

And Esther Burkett, the Fish and Game wildlife biologist responsible for the preserve, said it is possible that the birds might return as early as the first week of April.

The construction work “has to be done in time. It will be done. I will do everything in my power” to see that it is done, Burkett pledged.

However, the Caltrans project will go on during the entire April-through-August nesting season. To lessen the impact, highway environmental engineers have planned an elaborate sound monitoring system, a 150-foot-long sound wall and quieter pile-driving equipment.

Still, Caltrans environmental planner Charles Larwood asked rhetorically: “Would I want to be a least tern next to this project? In a perfect world, I’d rather be on a desert island. But the idea is trying to reduce the impact. . . . Everybody--including Caltrans--is very concerned about the least terns.”

Also concerned is Gordon Smith, chairman of the board of directors of the nearby Huntington Beach Wetlands Conservancy.

“I’m hoping highway construction won’t disturb the terns. But some of us were joking the other day--’How are these terns going to sit on their nests when they’re bouncing up and down four inches from the pile drivings?’ ” Smith said. “I wouldn’t think that would be good for their eggs.

“So many people have worked so many years to develop a nesting colony,” he said, “I’d sure hate to see it spooked away by this activity.”

The smallest of 39 species of tern, least terns have had their share of troubles.

At the turn of the century, the nine-inch-long, gray-and-white shore birds flourished from the southern tip of Baja California to Monterey Bay. Thousands of them once nested in Orange and San Diego counties. And in 1909, one bird-watcher wrote, the Huntington Beach nesting site was a vigorous colony of 600 nesting pairs.

But as rapid development reduced their terrain, least tern colonies declined. By last year, Fish and Game officials counted only 1,230 pairs in California, 70 at this site.

In recent years, this colony’s predators have included sparrow hawks, red foxes, crows, cats and also man. In 1986, biologists said, someone broke into the fenced preserve and, accompanied by a dog, walked from nest to nest, breaking or taking eggs. That year, 69 least tern pairs laid eggs but the colony produced only 34 fledglings--young birds that could fly.

Last year’s record was even worse. Seventy nesting pairs produced only five fledglings. The problem last year, Burkett said, was sharp-eyed kestrels, also known as sparrow hawks, that can spot the terns’ salt-and-pepper-colored chicks against the sand and then swoop down on them with deadly accuracy.

The chicks’ cover is “minimal,” Burkett noted. Demonstrating that point, she knelt and gently scooped a hollow in the sand, building an approximation of a Spartan and unprotected least tern “nest.”

To protect chicks this year, Burkett said she would be scattering clay roof tiles and driftwood around the preserve--hoping to give the chicks a place to hide, hoping “to prevent the kestrels from nailing them.”

This year as in previous years, a biologist is to visit the preserve at least once or twice a week through the nesting season to count eggs and chicks.

But this year’s construction plans have added a new dimension to monitoring the terns. Burkett is hoping Caltrans’ impact on the colony will be minimal. After all, she noted, some least terns in San Diego nest beside the airport runway at Lindbergh Field.

Still, she and other biologists will be watching carefully for signs of distress.

They will be looking for changes in courtship behavior, she said. (Typically the male bird courts the female by bringing her fish. After she accepts it, they mate and both share the duty of incubating the eggs.)

But if construction work upsets the terns, “we might notice abandoning of eggs,” Burkett said.

“Or we might find a lot of dead chicks, chicks not fed,” she said, signs that the noise of construction prevented them from hearing their parents’ cries as the adult birds returned to the nest with fish.

Burkett is hoping that use of “vibratory” pile drivers instead of “hammerhead” pile drivers on the bridge will keep noise levels down. By agreement with Fish and Game, Caltrans is supposed to keep its noise levels below 62 decibels--about the sound of normal conversation.

Also, Caltrans is to build a sound wall of plywood and telephone poles--16 feet high and 150 feet long--on the eastern edge of the preserve. Caltrans’ Larwood noted, however, that they still must design some sort of impediment along the top of the sound wall “so birds of prey can’t sit there. We don’t want to make it easier for them” to catch the chicks.

In the end, Burkett said, this was an experiment to see if the highway widening project could coexist with the least terns.

And if it could not?

“If we notice something wrong with the birds, the project can be stopped,” she said.