Bats

Bats are so cool. I wrote an earlier article on bats but there's just so much to bats that make it hard to do them justice in a single article. Huge populations living just barely out of our sight that have just so many stories to tell make it hard to do them justice in a single sitting.

The bats in the video below are <a href=http://www.arkive.org/brazilian-free-tailed-bat/tadarida-brasiliensis/>Brazilian free-tailed bats</a>. Also known as Mexican free-tailed bats they are the most common bat in Florida. If you see a bat there's a better than even chance it's a Brazilian free-tailed bat. If you look closely at one you can see the little "mouse tail" trailing as they fly.

Brazilian free-tailed bats are given more credit than deserved for eating mosquitos. Sure, they eat a few but the prefer larger insects like moths and flying beetles. Just not enough meat on mosquito body to go after them. Some surveys have found over 90% of their food to be moths.

I took pieces of the video above at a nearby bridge. I used a very weak light to shine into their crack and went by pretty quickly to get a video of them. Not a very good video but look closely and you can see a couple. Lousy video is the price of minimal disturbance. The last piece is some stock photos but the sound in the background is the bats that I recorded. In the daytime when you hear them it's a very high pitched squeak. As evening approaches they get more excited and start giving lower pitched squeaks that you hear at the end of the video. They know feeding time is near.

My what large ears you have!

The day we went to the bridge to watch them come out a Cooper's hawk joined us. He spend the evening sitting on an unused man-made bat house watching thousands emerge from the bridge, seemingly as fascinated as we were. He never tried to catch any of the emerging bats while we were there, but bats to make up a part of their diet. I think we may have intimidated him from trying on that day.

Bat on the menu?

Right now a vital time of year for the bats. The young were born in June so the mother is feeding the babies. All of the young in a colony are born in a period of 10 days. The males left just after the mating in March so the population of the bridge doubled when the babies arrived. They males fly to the south to give the mothers all of the insects in the neighborhood. As soon as the pups are able to hunt the mothers will fly away and leave the area to the young bats.

In some ways Brazilian free-tailed bats seem to be survivors. They depend on a variety of insects in their large range that extends from the south of Brazil to the south of the US. They can live in a large variety of homes -- caves, mines, bridges, old buildings and trees all fill the bill for habitat.

The bat signal is on

But they're not very resilient to pesticides. Agricultural pesticides are particularly hard on bats. Sprays frequently slow insects without killing them immediately. Bats feeding near a recently sprayed orchard or field can be devastated quickly. Bats eat many insects every night, and their body is very small. They take in a lot of pesticides compared to their body weight.

But I guess the reason I really like the Brazilian free-tailed bat is their ability to hide in plain sight. Bridges have become a favorite haunt but exceedingly few of the cars passing by know that thousands of bats may live in the bridge they just crossed. Nor do they realize the number of night insects that are consumed every night.