Eckert James River Bat Cave Preserve

Southwest of Mason, an unremarkable limestone cave on the James River holds one of the largest bat nurseries in the country. About four million female Mexican free-tailed bats arrive in May and stay through September. Most give birth to a single pup in June, and the young join the evening flights at about five weeks old. The bats return to Mexico in October.

The cave's history belongs to the Eckert family. W. Phillip Eckert bought the ranch in 1907 and mined the bat guano in the early 1900s, selling it to local farmers as fertilizer. His son Lee carried on the work and the care of the bats until his death in 1967. In 1990 Richard Phillip Eckert and Virginia Eckert Garrett gave the cave to The Nature Conservancy in honor of their father and grandfather, on one condition: that the land around it stay open to the public, as it had been for more than a hundred years.

Visits are seasonal and centered on the evening emergence, when the bats leave the cave to feed over the Hill Country. The Conservancy announces each season's dates; the preserve is closed between seasons, and the schedule is posted in early summer.