Bird watchers are blasting the Highway 101-Petaluma River Bridge construction project, saying contractors hung a net that is supposed to protect birds but is instead killing them.
The three-year project, which got under way this month, includes netting hung on the underside of the bridge to prevent migratory swallows from nesting there during construction, protecting them from danger.
But the netting has had just the opposite effect, said Veronica Bowers of Sebastopol, director of the Native Songbird Care &amp; Conservation advocacy group.
"The birds are alighting on the net, which is very loose and tangled around," she said. "They are becoming entangled. But worse is that there are entry points where they are climbing in and becoming trapped in the interior. They're being left up there to die."
Caltrans spokesman Bob Haus acknowledged there is a problem with the netting, which was hung Feb. 15.
Thirty-four dead birds have been documented, he said. Bowers said her group is continuing to document deaths. On Sunday, she said 17 dead cliff swallows and 1 barn swallow were counted hanging in the netting.
Workers at the site noticed a problem March 27, Haus said, and Caltrans reported the issue to federal and state wildlife agencies.
"We've been working with them ever since then, providing them with five-day reports," he said.
Workers are out closing the gaps in the netting. He said the contractor has also just received a more durable and more visible net that is being installed.
"It's kind of a slow process because it's underneath the bridge, and you have to have lane closures at night. Plus, they're working over water, which makes it more complicated," Haus said. He said the work should be done by Sunday.
Bowers said she notified Caltrans a month ago that the netting was too loose.
"No one ever called me back," she said. "I left another message a couple weeks later. When I checked on Sunday, I was not surprised to see dead swallows."
Cliff swallows spend about six months of the year in South America and make the 14,000-mile round-trip journey to nest here in early spring, building mud nests on natural and man-made structures.
Cliff and barn swallows have been nesting on the bridge for decades, Bowers said, and have a "very strong nest site fidelity."
Swallows and other birds are protected by the federal Migratory Bird Treaty Act and state fish and wildlife codes. Possessing, killing, harming them or disturbing active nests can be violations.
U.S. Fish and Wildlife Service spokesman Michael Woodbridge said Thursday his agency's law enforcement division is investigating the problem.
"All I can really say is that we're looking into it," he said. "Because it's a law enforcement issue, we can't comment on it."
He said he didn't know whether Bowers' complaints or Caltrans' self-reporting triggered the investigation.
"The netting was sloppily applied. It is loose and not properly secured to the bridge structure," Bowers maintained. "There are numerous points where the birds can squeeze between the netting and the structure . . . where they become trapped.
"Caltrans should be held accountable for every bird that dies in the netting."
Janice Mackey of the state Department of Fish and Wildlife said a Caltrans biologist is "closely coordinating" with federal and state officials to fix the problem. She didn't know whether Caltrans would face any enforcement action.