Last night BCI (Bat Conservation International) had a members night at the Bracken Cave, located northeast of San Antonio. This cave, normally closed to the public, is the home of millions of Mexican free-tailed bats. It’s the largest breeding area for bats, and is the largest collection of mammals in the world–in other words, there are a lot of bats here (estimated at 20 million).

We left Austin early, since you never know how traffic will be. The 70 mile trip ended up taking about an hour fifteen, as the roads were clear (once we got out of Austin). Since we were so early, we drove around the area. Evelyn spotted a number of military aircraft flying about, so we figured there must be a big airforce base around there (later confirmed).

Stopped at the local Super Walmart to see what they had, and I was able to pick up some good chili powder and onions. Why onions? Well, for some reason I can’t find any non-spoiled onions in the area! We’ve gone to four different grocery stores so far, and I can’t find an onion that doesn’t look like it’s been sitting in the bin for 6 months. It’s the great onion shortage of 2007, and it really sucks, since nearly everything I make uses onions. Maybe there was some sort of problem with the crops, or they are out of season, I don’t know. Anyhow, I did find some reasonable small ones, though their large onions looked just as bad as those in the Austin stores. I can find chutney, I can find 5 different kinds of salt, I can find exotic spices, but I can’t get a fricken onion!

Enough of the onion rant. We next headed toward the junk food aisle, so we’d have something to munch on while looking at bats. There I found a bag of the biggest pork rinds I’ve seen. Your garden variety pork rinds are about the size of your thumb, or potato chip size. Not these babies. The small pieces were the size of your outstretched hand! It was like you took the whole pig skin, fried it up, and put it in a bag. While tempted to purchase such large pork rinds, I decided to hold off and perhaps get them as birthday gifts.

We ate, drove around a bit more, and then headed toward the cave. It’s on nearly 700 acres of private property and is not marked at all. The hidden factor is on purpose, since they don’t want people disturbing the bats (there is no on-site security). We got there and waited for the other groups to arrive. Ended up being about 15 carloads of people, plus a van full of Japanese tourists (school teachers).

At around 6:15 everyone was there, so we started a caravan down a dirt road toward the cave. It’s about a 1/2 mile or so over rutted roads. Had to take it easy, since taking some of it too fast would bottom-out the car. I felt like I was driving on some PR roads again!

We got to the cave entrance and were greeted by one of the caretakers. He runs a company that “mines” the bat guano from the cave (to sell as fertilizer). An old-time Texan, he began telling us about the history of the cave. One interesting story was that the US Army took over the cave during WWII. They were using the guano and–get this–experimenting on bats as weapons. You see, the plan was to tie little fire starting devices to the bats and then release them over Japan during the day. Since it’s daylight, the bats would go for darkness (ex. the eaves of peoples houses) and then the fires would start.

“Uh, oh.” I said to myself, looking over to the Japanese tourists, “this isn’t going to end well. I sure hope he notices all the foreigners in the audience.” Well, the old guy didn’t and continued on: “It didn’t work out in the end, which is a shame, since it would have been better to burn down all the Japanese houses than drop the bomb.” Evelyn, the expert photographer, managed to get some pics of the poor teachers’ faces as the old Texan told his tale. Comedy gold! 

Next, we set up our chairs near the entrance (about 100 years away) and waited for the bats. It was overcast, and a bit chilly, but it wasn’t raining like earlier in the day. At around 8:15 the large groups started coming out of the cave. It’s a constant stream of bats, flooding out of the entrance (entrace is about 50 feet across). We walked around the entrance a bit, and there was one area where you could stand while the flood of bats flew right over your head.

It was a very cool experience, and we plan on going back in the summer, when the babies have hatched. That time is supposed to be very amazing, since the population is closer to 30 million bats at that time. Regardless, this “off season” night was still a sight to behold. It’s incredible seeing so many animals emerging from one place. They just keep coming and coming and coming.

There are so many that they–along with the moths they eat–show up on Doppler Radar. On the radar you can see the mass of bats moving toward the mass of moths (they both show up as rainclouds), they meet, and everything scatters. During the early days of Doppler the weather service kepts predicting huge storms as two rain masses headed straight for each other! Only later did they discover that it was the bats and the moths.

For those of you who want to visit Bracken Cave, please keep in mind that it is only open on special nights throughout the spring/summer for BCI members. Also, you can not actually go into the cave. You mainly sit outside (bring your folding chairs and snacks) and watch the bats emerge during twilight. For those of you who want a similar experience, though with less bats, check out the Congress Avenue bridge in Austin during the summer.  There are also bridges and other caves around San Antonio that have large bat populations, and the second-largest colony is in Mason, which is about 100 miles northwest of Austin.