Swallows resume nesting on Petaluma River Bridge

As avian aficionados know, cliff swallows are tenacious creatures, birds that return to their preferred nesting locations decade after decade.

And so they’ve returned again to the Highway 101 bridge over the Petaluma River, after causing disruption to the four-year highway widening project and endangering their nesting rituals.

A coalition of environmental groups and animal activists sued Caltrans in 2013 after more than five dozen birds died in netting the agency erected to try to prevent the birds from building their conical mud abodes in the safety of the concrete bridge supports.

About 800 of the birds - which are protected by the federal Migratory Bird Treaty Act - have returned to the bridge area this year, Caltrans spokesman Allyn Amsk said.

They are being allowed to freely nest on the underside of the newly constructed center lanes of the bridge and portions of the old southbound lanes of the bridge. But Caltrans is trying to prevent them from nesting in active construction zones by erecting plastic sheeting and hand-scraping or pressure- washing to remove the beginnings of nests.

Bird lovers are keeping an eagle eye on the work, which was signed off on by both sides in a three-year settlement agreement.

“We’re concerned that they’re not being proactive enough,” said Veronica Bowers, director of Native Songbird Care and Conservation, one of the groups that has pressured Caltrans to protect the birds. “It requires daily action on their part. We’re concerned that it’s not happening and we’ve seen some evidence to support that.”

Susan Kirks of the Madrone Audubon Society is monitoring the work daily. She said Caltrans’ efforts have been insufficient so far.

“It is clear their exclusion plan has not succeeded, and our interest includes ensuring regulatory agencies are aware of the current situation and Caltrans’ practices of nest-start and nest removals, which are occurring,” she said.

Caltrans maintains that no baby birds or eggs are being destroyed.

“Removal of nest starts is occurring according to the plan, and there has been no take of a migratory bird or egg in the 2014 nesting season or in the 2015 nesting season to date,” Amsk said.

The lawsuit and settlement protections for the birds added six months and $5.5 million to the cost of the $130 million project, according to Caltrans.

Cliff swallows spend about six months of the year in South America and make the 7,000-mile 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, the activists say, and have a very strong “nest site fidelity.”

They are protected by federal law and state fish and wildlife codes. Possessing, killing or harming them or disturbing active nests can be violations. The U.S. Fish and Wildlife Service fined Myers Inc., the contractor that installed the nets two years ago, $3,525 for harming them.

Caltrans plans to demolish the old span on Aug. 16, the day after the nesting season ends, unless fledglings remain.

While Amsk said Caltrans biologists have observed nesting to be finished by mid-July in the past two years, Bowers said it’s not unusual for her group to get baby swallows at the end of August.

“If any active nests remain at the southbound Petaluma River bridge on August 15, Caltrans will adjust the construction schedule accordingly,” Amsk said.

You can reach Staff Writer Lori A. Carter at 521-5470 or lori.carter@pressdemocrat.com. On Twitter ?@loriacarter.