July 15, 2005  


A western bluebird sighted at SLAC.
(Photo by Diana Rogers)

Breeding Bluebirds

By Monica Bobra

Since May 2004, miniature wooden houses have hung from various trees around the SLAC campus (see http://www2.slac.stanford.edu/tip/2004/may07/nest.htm). Constructed to accommodate a dwindling species called the Western Bluebird, the six homes were simply an initial trial “just to get an idea of bluebird activity,” said Kirk Stoddard (EPR). Now SLAC plays an active role in Western Bluebird preservation.

Currently, there are six hundred Western Bluebird homes in San Mateo County, eleven of which hang on SLAC trees. Of these, five contain bluebird nests, while three lodge nests of other birds: the Bewick’s Wren, Chestnut-Backed Chickadee and Plain Titmouse. Both Stoddard and Juana Rudati (SSRL) monitor the homes weekly during the nesting season, which runs from February to July.

The 25-square-inch homes were supplied by Howard Rathlesberger of the California Bluebird Recovery Project, which is part of a nationwide effort to bring the bluebirds back to their natural habitat. The five-inch-tall birds build their nests in the cavities of rotting trees called snags. However, most construction workers uproot snags, unaware that they are an incredible resource—a whole ecosystem in itself, according to Stoddard. SLAC doesn’t uproot such trees, he reported, unless they present a safety hazard.The birds easily slip through the 1.5-inch diameter hole on the front panel of their home, specifically constructed to let in only the Western Bluebird.

However, more aggressive birds like the woodpecker have enlarged the holes and stolen the bluebirds’ homes. As a result, Stoddard replaced the woodpecker-damaged wooden boards with a metal plate pierced with a 1.5-inch diameter hole. Now the woodpeckers stay away.

A month ago, a member of the San Francisco Golden Gate Chapter of the North American Bluebird Society spotted a Western Bluebird in the former Presidio in the first recorded sighting of a San Francisco-residing bird since 1936, according to Rathlesberger. “The western bluebird kind of left the cities and now we’re getting them to come back,” he said, calling it a tremendous achievement.

One of the reinforced birdhouses is suspended from an oak tree behind Bldg. 280C.
(Photo by Monica Bobra & Topher White)

Hundreds of county-wide bluebird organizations report to the North American Bluebird Society, pioneered by Lawrence Zeleny in March, 1978. Birdwatchers identify the Western Bluebird by its reddish breast, white belly, and bright blue wings and throat.The Western Bluebird, however, is not on the endangered species list. Why, then, are so many people devoted to preserving this small, friendly animal? “My guess would be the role that the bluebird plays in popular culture, which is an old, well established one,” said Mitch Snow, a spokesperson for the U.S. Fish and Wildlife Service. Rathlesberger has a different opinion: “Well, because the bluebird is really attractive,” he said. “You just fall in love with it.”


The Stanford Linear Accelerator Center is managed by Stanford University for the US Department of Energy

Last update Monday July 18, 2005 by Topher White