SACRAMENTO (CBS13) – Bats have made a home under Highway 50 in Downtown Sacramento, so Caltrans has nailed cones to the bottom of an overpass to get rid of them.

But one ecologist has a problem with it.

Drivers in Downtown Sacramento traveling underneath different sections of Highway 50 are noticing a different kind of traffic cone. It’s not meant to block cars from traveling in a given traffic lane. They’re underneath the bridges to block another group who frequents the overpasses.

“The bat removal devices are under U.S. Highway 50 to defer the bats to migrate to another location in order to mate for the winter season and the spring season,” Angela DaPrato, a Caltrans Spokesperson, said.

Thousands of bats and different birds will climb up into holes in the overpass designed to let out water and make it their homes. But, with a $433 million widening project for the freeway scheduled to happen in the near future, Caltrans wanted to make sure these critters weren’t in the way of the project.

“There are a lot of bats that actually migrate elsewhere during the winter. But, there are some that stay during the winter season,” DaPrato said. “And for those bats we are trying to deter them to another location in the Sacramento area.”

The cones are designed for one way out with no way of reentering for these animals who are used to roosting and living in the overpass.

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“You’re excluding them from home. So, where are they going to go?” Dr. Fraser Shilling, an ecologist at UC Davis, said.

Dr.Shilling specializes in researching the impact of traffic projects have on the environment, specifically on wildlife. The removal devices do raise some concerns for him.

“Because it’s the middle of the winter. It’s not a time when bats are normally moving around or a lot of birds unless they’re migrating,” Shilling said. “So any bats or birds that are excluded from those bridges, it’s possible that they’ll just go somewhere else to die.”

Caltrans understands there are concerns with devices. But, the agency told CBS13 it has seen successful removal of bats and birds in other projects on Interstate 80 that happened from Roseville to Rocklin that didn’t cause much of an impact to the critters.

The agency hopes to have the same success that it has had in previous projects.

“Based on the survey that we have done in the past with the other project, the environmental impact for the bats aren’t that great. This is a very safe device for them,” DaPrato said. “What we have found in the past is that the bats do migrate back after a project is done.”

Caltrans said that the widening project is expected to bring a sound wall and an HOV lane in both directions on Highway 50 from Interstate 5 to east of Watt Avenue, among other traffic enhancements.

Construction is expected to start next month and finish in December of 2024 or 2025.