Bats exiting the entrance to the Old Tunnel which many years ago was a railroad tunnel cut through the hill.
When the railroad was disbanned, the bats came to nest and make it their home.
The State of Texas purchased the area to assist in protecting the bat population. South Texas has over 40 millions bats.
The bats in this nesting area consume over 13 tons of crop insects each night.
Without the bats and their efforts, several Texas crops would soon be destroyed by insects.