Bat Night 2011

Around this time of year in Southern Arizona we have nectar bats visit our hummingbird feeders. The type of bats that visit our feeders are called the Lesser Long-nosed bat (Leptonycteris curasoae yerbabuenae). This species is listed as endangered under the Federal Endangered Species Act.

For the past three years we have signed up as part of a study by Arizona Game and Fish Department and U.S. Fish and Wildlife Service that keeps data on bats that visit hummingbird feeders in the Tucson Basin. We monitor the feeders and record on a webside when we see bats at the feeders and how much the sugar water level dropped that night. The study has a website hosted by the town of Marana to learn more about the study go to

In the past and again this year, we have been lucky enough to have the bat biologists come out to our house to trap a few bats for the study. If you would like to see past Bat Night posts visit and

This year the bats arrived early. We saw our first bat on July 26th. In previous years we have not seen bats until late August or early September. This past winter our area got little rain and a very hard freeze, possibly harming some of the native plants the bats feed on. We have not only seen the bats earlier than normal but we are seeing way more bats than we usually do.

OK now on to Bat Night 2011

The first thing the biologists do is scope out the area and decide where to set up mist nets. Lesser long-nosed bats actually have pretty good eyesight and often avoid the nets.

Here is a close up of the net. The fibers are very thin almost like the old style hair nets women used to wear. Once the nets are set up it is time to sit back and wait.

It didn’t take long this year to catch the first bat. At 8:11 pm. this juvenile male was caught. Here is the biologist carefully removing the bat from the mist net. They caught 6 bats this night. two juvenile males, two juvenile females, one adult male and one adult female.

The photo above shows not only another bat caught in the mist net but how thin the net really is. Some of the bats can get pretty tangled up at times. The biologists are very careful removing the bats from the net as not to hurt them.

Here is a close up on one of the bats, they are very cute. If you take a look at this bats legs you can see that the membrane between its legs is cut up high as if it is wearing pants, that is an easy way to tell it is a lesser long nosed bat. Some people also have the Mexican long tonged bat visit their feeders, we have not seen any of them here but an easy way to tell if you have Mexican long tonged bats is that membrane between the legs is long, it makes the bat look like it is wearing a skirt.

Above you can see a close up of the bats face. Lesser long nosed bats are part of the leaf nosed bat family (Phyllostomidae). If you look at this bat’s nose you can see that it kind of looks like a leaf.

Once the bat is trapped and out of the net the biologist measure the length of the bone in the wing, this bone would correspond to the bone in a human between their shoulder and elbow. Bats are mammals just like humans. Bats are the only mammal that can truly fly. Their scientific name Chiroptera translates from Greek into two words, hand wing. Bats do not flap their entire forelimbs, like birds do, but instead flap their spread out digits (fingers) which are very long and covered with a thin membrane called patagium. If you look at a bats wing spread out, and can imagine your own arm and hand, you can see where the name comes from.

Next the biologists swab the bat’s muzzle for pollen. Lesser long nosed bats normally feed on night blooming plants. They are one of the main pollinators of columnar cactus like the saguaro cactus along with the agave. Agave is used to make agave syrup and tequila. In the absence of bats, the seed set of the agave falls to one-three-thousandth of normal.

The biologists also inspect the bat for over all health. The bat above is an adult female, the biologists can tell she was a nursing female by seeing that the fur around her nipple is missing. The lesser long nosed bat’s mammary gland is shown in the photo above, near the arm pit (wing pit) not sure what you call that. See how the fur is missing? That shows she had a baby bat this year.

The last step is to weigh the bat. After this the bat is let go. The biologists mark the top of the bats head with a little ink from a marker before they let it go, so that if they catch the same bat again, they don’t make it go through all the rigamarole again.

All the data from the bats is recorded. You can see above, so far 5 bats, time caught, sex, weight and so on.

This bat night we had two interesting visitors stop by, both were male tarantulas. This time of year the males step out and about looking for a female to mate with.

The bats are hungry this year. Hope you enjoyed Bat Night 2011

For more info on bats see

Bats in slow motion Nectar bat’s tongues

~ by Meg on September 1, 2011.

5 Responses to “Bat Night 2011”

  1. I’ve just added your site to my bookmarks. Great posts. Thanks!

  2. Wow Meg….this is awesome stuff! Thanks for the great education around bats. Being in the Southeast (truly the land of the mosquito!)….we LOVE bats. Would love to learn more about the bats in this part of the country.
    Love & Hugs….Glo

  3. Fascinating – wonderful photos of the bats!

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