Up to 250,000 bats under a Yolo County bridge? Here’s why and how to see them

Bats don’t always live in caves. In California, the largest urban colony of Mexican free-tailed bats live under a busy interstate in Yolo County, according to the Yolo Basin Foundation.

At its height, roughly 250,000 bats make up the colony.

Starting in late June, droves of female bats fly to join the growing maternity colony under the Interstate 80 Yolo Causeway; many people come out to see them take flight.

Throughout the summer, the Yolo Basin Foundation, an educational and environmental nonprofit, offers opportunities for people to learn more about these bats. Registration is now open for the 2022 bat program events.

This year’s programs include a virtual Bat Talk and an in-person Bat Walk for people to learn more about the nocturnal winged mammal. Both events feature up close viewing of “live ambassador bats.”

Bat Talks, hosted by the foundation, go into more detail about bats, their natural history and role in the ecosystem. The first one takes place June 28 at 6 p.m. for 45 minutes on Zoom. It is recommended to attend a talk before registering for a Bat Walk.

In the maternity colony, female bats give birth to their pups, and after a few weeks, they fly in the evenings across the Central Valley for food, eating mosquitoes and other pests.

The two-hour “walk” (which isn’t actually a walk) begins at the Yolo Bypass Wildlife Area Headquarters, in which guests remain in their cars and drive through wetlands and rice fields to witness the bats’ evening flyout. The first available event takes place on June 26 at 7:45 p.m.

Tickets are $15 for adults and $5 for children between 6 and 17 years of age. Children under 5 enter free.

The foundation is also holding two craft sessions for children on July 9 and Aug. 13 from 10 a.m. to noon.

These special events are aimed at children between ages 3 and 8, who will also have the opportunity to meet live bats. Registration is $10 per child and accompanying parent.

The foundation also invites school field trips and church groups for private events. The maximum number of attendees is capped at 60, and tours start at $400.

For all of the foundation’s events, registration and more information is available on its website.

This story was originally published June 9, 2022 at 9:29 AM.