Caltrans to Erect Screens at Work Site to Protect Nesting Swallows : Santa Clara River: The giant pieces of mesh will allow the $15.7-million bridge project to proceed during the mating season.

The California Department of Transportation will use giant mesh screens to shield nesting swallows from noise and debris this summer when a new bridge is built across the Santa Clara River.

The $12,000 project will represent the first time that Caltrans has sought to protect bird habitats near a construction site, spokesmen said Wednesday.

Biologists from the U.S. Fish and Wildlife Service urged that Caltrans take the action to shield the swallows from noise, debris and visual impacts during construction of the $15.7-million bridge near Saticoy.

Their concern was that noise from the site would hinder breeding of cliff swallows, which are protected under the Migratory Bird Treaty Act and come to the area each spring.

The 12-foot-high hanging screens, constructed from a heavy cloth netting, will allow the project to go forward during the birds’ summer breeding season, Caltrans spokesman Russel Snyder said.

The project cannot be delayed until fall, when the swallows finish their mating season and return to South America, because the riverbed is a flood channel and construction is not allowed between Nov. 15 and April 15.

“We’re under pressure from people who want that bridge built, and we can’t afford to lose a whole season, so we’re doing what we have to do to get things under way,” said Stan Lisiewicz, Caltrans deputy director of construction and maintenance.

“If it costs us some extra money, well, that’s just the cost of doing business,” Lisiewicz said.

Business was interrupted in this case by a small, rust-colored bird that annually migrates from South America to breeding sites in California.

A favorite nesting site for the birds is the underside of freeways, where their cone-shaped, mud and twig nests have become common sights.

Biologists involved in the decision praised Caltrans for its concern. “Caltrans is trying to be a responsible agency throughout,” said Fish and Wildlife Service biologist Cathy Brown. “And remember, the reason this is an issue is that these birds are protected.”

However, another Fish and Wildlife Service agent pointed out that Caltrans did not have to take the action, because disturbing migrating swallows is not an offense under the Migratory Bird Treaty Act.

The act prevents people from pursuing, hunting, capturing, killing or attempting to take the birds, special agent Marie Palladini said.

“If you go by the letter of the act, yes, we did not have to do this,” Caltrans natural science specialist Paul Caron said. “But we have chosen to follow the spirit of the act, which is to say that we don’t want our construction project to inhibit their breeding.” The action by Caltrans comes on the heels of an environmental controversy involving the agency in San Bernardino County.

Caltrans employees are accused of damaging areas of the desert that are home to several endangered species in one incident earlier this month and of ruining a pristine, wild trout stream by dumping tons of gravel earlier this year.

Lisiewicz denied that there was any attempt to shrug off alleged wrongdoing in San Bernardino County by highlighting preservation efforts in Ventura County.

“This is just a coincidence. We decided to do this because it was recommended as the most effective way to deal with a protected species,” he said.

“The same thing would have been proposed if the swallows would have shown up six months earlier or six months from now,” Lisiewicz said.