Water District Recruits Birds in Its War on Bugs

A Central American swallow with a ravenous appetite for insects is being courted by water quality officials who hope the tiny birds will take up residence along the bug-rich Santa Ana River.

To make the swallows feel welcome, Orange County Water District officials on Tuesday unveiled a master-planned community for the birds--a group of 100 blue-gray birdhouses in an area where the river curves through Anaheim and Orange.

It is hoped the tree swallows, which eat three times their weight in insects a day, will breed and raise their young in the area. The natural insect control program, which is already underway in Riverside and San Bernardino counties and is being coordinated by the water district, is intended to reduce the amount of pesticides needed to combat the spread of insects.

Just in time for the swallows’ March and April breeding season, biologists are hanging the nesting boxes about six feet off the ground on posts as well as on eucalyptus, pine and willow trees along the riverbank.

“Hopefully, we can start building a master-planned community of tree swallows this spring,” said Patrick Tennant, an environmental specialist with the water district.

The small circular entrances on the boxes are designed for western blue birds and tree swallows. The tree swallows--a greenish-blue bird that grows to 6 inches in length--are common in wooded habitat near water and where dead trees provide nest holes. They migrate in huge flocks and linger farther north in the fall than other swallows.

“We’re basically after tree swallows,” said Dick Zembal, natural resources director for the water district. “They’re aerial acrobats. They take insects right out of the air and eat hundreds and hundreds a day.

“When they’re feeding their youngsters, they can really put a dent in the insect population,” Zembal said.

Zembal said the bug population along the riverbed has been growing at an annoying rate.

“Every year, we get complaint after complaint about mosquitoes and gnats,” Zembal said. “The gnats fly right up around your face, swarm in numbers around your mouth, nose and eyes. And the mosquitoes are the disease carriers.”

Biologists will monitor the wood bird boxes to ensure that bees and even small mammals have not taken up residence in them. The water district is asking residents to help build the start-up community by hanging boxes themselves. The birdhouses cost about $20.

“This is a great Scout project or one for a homeowners association,” Zembal said. “Wherever there are people living [near] the river in Orange County is where we are targeting.”

Zembal said it will probably take some time to evaluate whether the program has been successful.

“The goal is to perpetuate the program,” Zembal said. “The evaluation window is probably at least 10 years.”

The district plans to put bands on the young swallows’ legs to track how many return the following year.

But tree swallows might not be the only weapon against pesky insects. The water district is considering installing shelters for bats, which are also insect eaters. The district is also considering constructing archways along the river to attract another insect-loving bird--the cliff swallow, the same ones that return to San Juan Capistrano every year.