What Are The Upside-Down Cones Stuck Under Sacramento Freeways? A Way To Save The Birds And Bats.

By Mike Hagerty

If you’ve noticed what looks like upside-down traffic cones stuck to the underside of freeway overpasses in the Sacramento area, you’re not alone. It’s an inventive plan to save the birds and the bats.

You can see them under the overpass for Highway 50 near downtown Sacramento, the stretch often called the W-X Freeway. The orange cones on the underside started showing up in mid-December.  

Each covers what’s known as a “weep hole,” a place moisture can drain out of the roadway.  When they’re dry, though, birds and bats fly into them to nests hidden inside the structure.

A cone under US-50 allows bats to leave but prevents them from returning to inside the overpass, Tuesday, Dec. 29, 2020.Andrew Nixon / CapRadio

Caltrans is about to begin a widening project on this segment of the freeway, and that work could scare mother bats and birds from their nests, abandoning their young.  So engineers and biologists came up with the upside-down traffic cone.  

In the hole at what’s usually the top of the cone is a tube with a sheath, which folds sobirds and bats can fly out through it, but they can’t fly back in.  Water can drain out of the cones too, as intended for the weep holes.  

It’s a trick Caltrans used during last year’s widening of Highway 65 in Placer County. A bonus? The cones are easily removable. So when the project is over, the cones will come off, and the freeway can be home sweet home for the birds and the bats once more.

CapRadio’s Mike Hagerty spoke with CalTrans Biologist Shawn Duffy about the devices and Public Information Officer Angela DaPrato about the “Fix 50” project itself.  

This interview was edited for clarity and length

Interview Highlights

On how the upside-down cones work 

Shawn Duffy: Ok, so this device is effectively a one-way doorway. There’s an opening in the bridge that’s there when it’s built to allow water to seep out. Essentially, it’s just a hole. Those cones are essentially a funnel, down to a smaller opening.

Then a the end of that opening is a PVC pipe that allows [workers] to attach plastic sheets on the outside, and that plastic kind of collapses on itself, and bends a little and so on, and makes it to where they [birds and bats] can’t actually get back in … there should be nothing that prevents them from leaving.

On how this idea came to fruition

Duffy: Somebody from down in the Fresno area had come up with this idea of what would let [birds and bats] out and not let them back in. We don’t want them being trapped in the bridge because they can perish from lack of water, and so on.

On the other hand, if you have nothing over [the weep hole], there’s no reason that they wouldn’t come back if you push them out.

On the timeline and progress of the highway widening

Angela DaPrato: Crews will essentially start construction on the sound wall that’s going to be on the south side of the freeway probably in January; we’re looking probably like the second week. Once that gets going, we’re looking at actual construction on the highway in mid-February or March. 

We’re saying spring of 2021. Once the project is completed, we’ll see a new HOV lane from Interstate 5 to Watt Avenue, and we’ll also see new pavement on the roadway.

On what will happen to the birds and bats once the freeway construction project is complete

Duffy: They’ll find their way back — perhaps not in not as great of numbers to begin with, but they will trickle back in as they find the location available. So it’ll be repopulated … maybe not even with the current generation, but certainly with future generation animals. We’re trying to make sure that we protect the species — That’s actually what this is about. 

[So when] the work will be done, we’ll take the devices back off and they’ll be able to repopulate that [overpass].