Wildlife advocates continued to press Caltrans and other state and federal agencies this week to respond to their mounting concerns over bird deaths under the Highway 101 bridges in town and the netting installed there that they say is causing those deaths.

The affected birds, cliff swallows, migrate to the area from South America each year to build their mud nests underneath the highway bridges. They are protected by the federal Migratory Bird Treaty Act.

This year, work on a massive Highway 101 widening project is getting underway, including expanding the bridge where the swallows like to nest. Caltrans' contractor applied the netting in an effort to keep the birds from nesting in the construction area, as is required by state and federal regulations.

Wildlife advocates say that the netting has been poorly applied and is trapping the very birds it is meant to protect, causing more than 100 of them to die a slow death while trapped within the netting since it was first hung in mid-February. They maintain that the netting is not effective because it gets blown loose at the windy locations under the bridges in town. They contend that an entirely different material, such as teflon sheeting, should be used to keep the birds out from under the bridge.

On Friday, about 30 wildlife advocates hailing from a range of local organizations showed up beneath the Lakeville Highway bridge to raise their voices and hand-made signs against the continued use of the netting and what they said is a lack of response by Caltrans and its contractor. A representative from Assemblymember Marc Levine's office was there as well to learn more about the situation.

"What's happening is baffling to me," said Sheri Cardo, a Petaluma resident and animal rights proponent who was at the protest. "Caltrans is not above the law. We just want Caltrans to take down the nets."

A national animal rights organization based in Cotati, the Animal Legal Defense Fund, joined local advocates' cries last week, sending a warning letter to Caltrans, the federal Department of Transportation and the Federal Highway Administration asking that the agencies "cease and desist violations of the Migratory Bird Treaty Act" and threatening legal action if the agencies didn't respond within seven days.

"We have a particular interest in this because it's in our backyards," said Danny Lutz, speaking for the group. "It's a particularly egregious act because the public transportation agencies know of alternatives (to the netting)."

The Madrone Audubon Society has retained legal counsel regarding the issue as well.

The ALDF received a preliminary response to their letter from the agencies last Friday saying that they needed more time to "fully consider (the) concerns about this important issue."

The letter promised a full response by May 1. "I assure you that the U.S. Department of Transportation and the Federal Highway Administration take our environmental and legal responsibilities seriously," the letter read. It went on to say that "all involved agencies are actively addressing this issue and have made significant progress in finding a lasting solution."

Caltrans spokesmen could not be reached for comment on Tuesday but spokesman Bob Haus told the Press Democrat in a recent interview that contractors had been working overtime every day of the week in an effort to stop the bird deaths. He said that Caltrans had documented 65 dead birds, in contrast to the higher counts by bird advocates, and had found none since April 19.

Haus told the Argus-Courier in an earlier interview that the netting has worked well in other areas.

After a public outcry first erupted in early April, Caltrans said the problem would be corrected within days. The agency's contractor, CC Myers, worked through the weekend to secure the netting. Caltrans announced a few days later that the problem appeared to be solved, but bird advocates have continued to count new dead birds in the netting.

It appears unlikely that those advocates will rest until they find no more birds in the netting, or until the material is removed.

"You know animal people," Sheri Cardo said at the protest. "We're not going away."

(Contact Jamie Hansen at jamie.hansen@arguscourier.com.)