In 1990, a Texas family donated a cave to protect its bats; today, about 4 million female bats use it as a nursery each summer

For centuries, a cave located in Texas was owned as part of a family property that has been used for some beneficial purpose. It was once a place where bat guano was collected and sold as fertilizer. However, in 1990, the family made a decision that transformed the future of the cave. Instead of exploiting the cave privately, the family donated it for conservation purposes. The Nature Conservancy states that, today, the Eckert James River Bat Cave Preserve has become a protected nursery where about 4 million female Mexican free-tailed bats arrive every summer to give birth and raise their young.

How a family-owned cave became a bat refuge

The Eckert family purchased the ranch containing the cave in 1907, and during the early 1900s, W. Phillip Eckert dug out the guano from the cave and sold it as a fertilizer for local farms. However, over time, the family’s relationship with the cave changed. While the site had once provided an economic benefit, later generations recognized that it also supported an extraordinary wildlife colony.


In 1990, the cave was donated by Richard Phillip Garrett and Virginia Garrett to The Nature Conservancy in memory of their father and grandfather, and the bats are permanently protected. The donation was accompanied by an important condition: the surrounding area would remain open for public enjoyment and education, allowing people to experience the natural event that occurs there every summer. Located in Mason County, Texas, the site now houses one of the largest bat nurseries in the country that provides seasonal shelter to millions of bats reliant on the cave during breeding season.

A nursery for millions of bats

Every year, the quiet cave changes when Mexican free-tailed bats return for the breeding season. Starting in May, millions of female bats arrive at the preserve and remain there through September. The cave serves as a maternity colony, where many females give birth to a single pup. Young bats remain with their mothers for several weeks until they can fly. By autumn, the colony begins its migration back toward Mexico. The cave is more than a resting place; it is a seasonal nursery where the next generation of the colony begins life.

Why one cave matters to the ecosystem

Mexican free-tailed bats are important for insect control because they eat large numbers of insects while flying at night. These bats help to control agricultural pests by eating insects like moths that harm crops. At night, the colony emerges from the cave and scours the surrounding landscape for food. However, large colonies also create a conservation challenge. When millions of animals depend on one location, disturbance or destruction of that habitat can affect an entire population. The species also has a slow recovery rate because females typically produce only one pup each year. Human disturbance during the maternity season can affect the colony, making careful protection necessary. To preserve the cave for future breeding seasons, conservation partners manage the preserve, monitor bat populations, and limit access during sensitive periods.

The science behind protecting a bat nursery

The preserve is also valuable because it provides scientists with a rare opportunity to study one of the world’s largest bat colonies. Researchers monitor the site to understand bat behavior, population changes, and the conditions needed to protect maternity colonies. The cave’s importance extends beyond the bats living inside it, as information collected there can help guide conservation decisions for other bat habitats.