Harvesting Bat Guano

Garden-Ville has been using bat guano on the farm and in the garden since 1959. Selling it in their store since 1970 and doing their own harvesting, from the Bracken Cave, which is only a short distance from Garden-Ville, since 1982.

The Bracken Cave is the largest active bat cave in the world. Each year, on Feb. 3rd, twenty million mother bats come from Mexico to the Bracken Cave to give birth to their young. While they are here they will deposit between 85 to a 100 tons of guano, per year, in the cave. In order to generate this much guano the bats, along with their young, will consume up to 200 tons of insects each night.

I have researched the Bracken Cave going back to1896 when first harvested by the Marbach Family. There is still some of the family in this area. One interesting discovery is, “no one has ever gotten sick from working in the cave and handling the guano, in fact, these workers seamed to be immune to even the common cold”.

When the Marbach’s first worked the cave they shoveled it into gunny sacks and cloth-lined the sacks out on a cable, later they dug a shaft down to largest area in the back of the cave and hoisted the bags out with a rope a over a pulley. By the late 1970s large vacuum equipment became available and it has been used every since.

The bats don’t give us very much time to do the harvesting. Some years they don’t leave for their winter home until a really cold spell sends them on their way. Which is usually November or later. Then we have to wait another ten days to two weeks for the guano beetles to finish their job of digesting the guano and any dead bats into a fine, better smelling product. Actually the product we harvest is more beetle poop than bat poop.

The shaft in the back of the cave, and the harvesting, has made the cave a better habitat for the bats. To show their appreciation the bats swirl up, each night, in enormous columns with a spectacular show. And when they are away on vacation they allow us to take from their summer home tons of the very finest plant food.

Malcolm Beck