Caltrans Maintenance workers install bat boxes under a bridge along State Route 33 near Ojai. Photo by District 7
Note: Public Information Officer James Medina wrote this story for the most recent edition of the Caltrans District 7 newsletter.
Bats!
They are creepy critters who are typecast as evil figures in movies — but in nature they are valuable allies who provide tremendous services.
“We like the bats because they eat up to 2,000 mosquitoes an hour at night,” said Newton Wong, an associate biologist in Environmental Planning. “They are part of the natural environment.”
In addition to providing pest control, bats are vital for agriculture because they pollinate plants and disperse seeds for new plants.
What do bats have to do with Caltrans?
Well, the small mammals like to roost in small colonies under highway bridges near water. One of their favorite spots is the State Route 33 Tule Creek Bridge north of Ojai in the Los Padres National Forest.
This view from below shows how bats can tuck themselves into tight quarters.
Photo by District 7
Before the bridge was rebuilt about 15 years ago, bats used to nest in the bridge joints under the overcrossing.
Caltrans devised an eco-friendly solution by building and installing bat boxes, small habitats that mimic a space between bark and a tree trunk — ideal for bats because they like tight, warm quarters.
Click on the image to see a short video of the bat houses’ installation.
Video by District 7
Six were initially installed, but the bat colony has since grown. This year, Environmental Planning built six more bat boxes that the Maintenance Division added to the bridge in May.
Asked if bats have attacked him, Wong said: “They fly near you but not at you.”
He noted that there are bat boxes at other highway locations in the Ojai area, as well as plans to mount them under the San Gabriel bridge over Interstate 210.
District 7 is not alone in implementing the innovative technique. Caltrans has installed similar bat boxes in Amador County and Merced County.