Spring means warm days, fragrant flowers in bloom and migratory songbirds returning to Sonoma County. It also means more work for Veronica Bowers and her Native Songbird Care and Conservation in Sebastopol.

Bowers and her team of volunteers rehabilitate injured birds and care for babies orphaned when people accidentally or intentionally destroy nests.

Her facility, the only songbird care center in Sonoma County, does most of its work during the nesting season between April and September. Bowers and her staff can care for up to 200 birds at any given time, diagnosing diseases, treating wounds and feeding them meal worms every 30 minutes.

Bowers has treated many of the 70 songbird species in Sonoma County, including bush tits, wrens and flycatchers.

"We're dealing with a huge diversity of natural history," she said. "Our whole purpose is to care for injured birds for release back into the wild."

Much of Bowers' time is spent caring for cliff and barn swallows. The birds spend winters in South and Central America and return each year to build their mud nests on bridges, under roofs and in barns.

People who don't like mud on the side of their houses or object to the bird droppings will destroy the nests and strand baby swallows, Bowers said.

"Our challenge is to let people know that swallows may be nesting on homes and tell them how to deal with them," she said.

Destroying active nests and harming migratory birds is a crime and punishable by up to a year in prison and a $10,000 fine.

There are a number of ways to keep swallows from nesting on structures, Bowers said. One of the most effective products is hard plastic sheeting, called BirdSlide, that can be installed in eaves and rafters. Another strategy is to scrape the nest starts before they are fully developed.

Plastic nets that some people install to deter swallow nests can end up entangling and killing the birds, Bowers said. That's what happened at a highway construction project at the Petaluma River Bridge last nesting season.

A Caltrans contractor installed nets that killed some cliff swallows. Bowers and other wildlife groups sued Caltrans. In a settlement, Caltrans agreed to remove the nets and install the plastic sheeting. They also agreed to give wildlife groups $4,000 to educate the public on swallow protection.

Bowers and the Madrone Audubon Society have been distributing fliers and meeting with Petaluma residents who can expect to see more swallows nesting in neighborhoods this year as construction continues on the bridge.

Susan Kirks of the Madrone Audubon Society said that people should welcome cliff swallows since they help keep the insect population in check.

"The cliff swallows nest close to wetlands and other areas with open space and water," she said. "They dine on insects, so they're natural insect pest managers."

Anyone who has found an injured bird, orphaned babies or abandoned nest with eggs can call Native Songbird Care and Conservation at 484-6502.

(You can reach Staff Writer Matt Brown at 521-5206 or matt.brown@pressdemocrat.com.)