A Hill Country bat preserve will reopen to the public this weekend, a little more than a year after a cloud of pesticide drifted over visitors to the cave from a neighboring ranch, prompting its closure.

The Nature Conservancy, a nonprofit conservation organization that owns Eckert James River Bat Cave Preserve in Mason County, on Tuesday announced dates in July and August when members of the public can come to the cave to see the emergence of millions of Mexican free-tailed bats.

The reopening comes after the Nature Conservancy and the owners of the neighboring Star S Ranch forged an agreement under which the ranch will not use pesticides in a way that affects the bat cave, visitors, or the group’s staff, according to the Nature Conservancy.

The agreement followed an evening in June 2018 when visitors saw a fog of pesticide wafting their way. More than 25 people who were gathered at the preserve to watch the bats swirl out of the cave saw Permethrin pesticides from aerosol sprayers drift across the fence separating the ranch and the preserve.

The Texas Department of Agriculture later fined the ranch $1,200 for violating state rules on pesticide use.

The preserve typically is open to the public to watch bat flights from mid-May through September, when the bats migrate south to Mexico for the winter. This year, it will be open on July 13, 20, and 27, as well as Aug. 3, 10, 17, 24, the Nature Conservancy announced.

The gates will open soon before the colony typically begins emerging from the cave. Conservancy staff said dates and times are dependent on the weather and the recent flight activity of the bats and urged potential visitors to call the bat cave’s hotline at (325) 347-5970 and listen to the recording for cave updates, open hours, and any weather-related closures before traveling to the preserve.

“We encourage visitors to come out and join us at the preserve’s open nights this summer and experience one of the best nature-viewing destinations in the state,” said Dan Snodgrass, director of land conservation at the Nature Conservancy in Texas, said in a prepared statement.

Brendan Gibbons

Brendan Gibbons

Brendan Gibbons is the Rivard Report's environment and energy reporter.