The adventurous are invited to join naturalists on the water at the Franklin-Thornton Bridge when bats fly out from the span at sunset to feed.
The bridge was built about 10 years ago with bats in mind enough room for thousands of the flying, bug-eating mammals.
An old flood-damaged wooden trestle and steel bridge that housed 40,000 bats over a floodplain and the Mokelumne River was torn down and the present span erected in its place.
Bat habitat was built into the new bridge's underside. The bridge designer planned dark recesses perfect for raising young bats.
Bats were forced to adapt to bridge life because former habitat sometimes the peeling bark of trees has gotten harder to find with deforestation.
The Sacramento County Department of Regional Parks and the Cosumnes River Preserve invite people with a watercraft to come see the fly-out. Volunteer naturalists will meet participants for the departure on water at 7:30 p.m. July 20 in the preserve visitor parking lot, 13501 Franklin Blvd.
Participants must bring their own canoe, rowboat or kayak, plus oars, paddles and life jackets. Motorized watercraft are not allowed.
The excursion is expected to last about two hours. Head lamps are recommended.
Call The Bee's Bill Lindelof, (916) 321-1079. Follow him on Twitter @Lindelofnews.