Bat Basics

Bat Basics

A little bit of background information before we get started creating habitat would be nice so let’s begin.

Bats are insectivorous. The diet of North American bats is almost exclusively flying insects and which ones they eat depends on what's available. They're nocturnal so moths are more likely to be a part of their diet than flies but they definitely eat mosquitoes. They use echolocation to be able to feed. If you go out after dusk to a rural area, chances are very good you will see small objects in the sky that look like boomerangs. Our bats have been having a field day thanks in part to the bumper crops of skeeters we’ve had lately and you’ll see them flying around feeding.

Kentucky Bat Working Group

These are the species we have in Illinois-
Federally Endangered Species: Indiana bat, Gray bat
State Endangered Species: Southeastern bat, Rafinesque's (Big-eared) bat
Uncommon: Keen's bat
Commonly found, hibernate in winter: Big brown, Little brown, Eastern pipistrel
Common to uncommon, migratory (found in Illinois only in summer): Evening bat, Red bat, Hoary bat, Silver-haired bat

Just to pique your interest, I’ve included a photo of a little guy that was stuck in a broken window that I rescued. Please note how tiny and vulnerable he is.



Bat Facts

Some interesting Bat Facts I’d like to share with you from Bat Conservation International, Inc.

-There are more species of bats in the world than any other type of mammal - over 1000 species. Nearly 1/4 of the world's mammal species are bats.
-The world's smallest mammal is the bumblebee bat of Thailand, weighing less than a penny
-The tiny wooly bats of West Africa lived in the large webs of colonial spiders
-There are frog-eating bats, and bat-eating frogs
-One little brown bat can catch 1,200 mosquito-sized insects in one hour
-Seed production in the agave plants from which tequila is made drops to 1/3,000th of normal without bat pollinators
-Wild specimens of important agricultural plants such as bananas, breadfruit, mangos, cashews, dates and figs rely on bats for pollination and seed dispersal
-Bats are the slowest reproducing mammals on earth for their size, making them exceptionally vulnerable to extinction
-More than half of American bat species are in severe decline or already listed as endangered.




The above orphaned bat was found clinging to brick by a young person just like you. Fortunately, the person who found her knew not to touch her. A wildlife rehabber was contacted and came right out to collect her new ward. This baby made it and was released back to the wild. Look at how small she is in relationship to the bricks.

Beyond the Basics

There is a wonderful book available that may be of interest to those wishing to learn more after today’s activity. “The Bat House Builder's Handbook” by Merlin D. Tuttle and Donna L. Hensley. It provides wonderful information and is most probably available at our local library.

We’ve learned at prior workshops that habitat housing design depends on the species.

We’ll create our bathouses based on meeting the needs of the species most prevalent in our area. In our general area we have the Big Brown Bat and the Little Brown Bat.

The blueprints we will be using were designed by a "batter" from the Mid West. Our completed product will be approximately 3' high by about 2.5' wide and is spacious enough to accommodate an entire colony. I will be sharing photos as well as copies of the blueprints for all of you to take home to share with others you believe might be interested in giving bats a “wing up” on habitat loss.

As mentioned previously, we have little brown bats and big brown bats in our area which are much more likely to use bat houses than many of the species of bats down south. They are also two of the species most likely to occupy buildings locally. The little brown bats and the big brown bats especially like their bathouses mounted up under the eaves.

For those interested in constructing another bat house using an entirely different design, here’s one that has expansion potential and the owner of the company is extremely well versed on areas of concern to batters and would be more than happy to spend time with anyone from this group who contacts him via his website.

Maberry Centre Bat Homes :: Welcome to the world of bats!

Here’s a sneak preview of a photo of completed bathouses constructed using the plans we will be using.



Some Things To Know Before We Install Our Creations

1) The primary function of a bat house is as a nursery/incubator. This is why they need to be exposed to sunlight in order to create the internal temperatures needed for the young to survive (over 100 degrees for many species).

2) In our area, painting the bat house is recommended to help to create the proper temperatures within the bat house. Here, we use a knights armor gray outdoor latex to better absorb heat. Lightest grays or reflective off whites for southern areas, medium steel grays or beiges and tans for our Midwestern area, and dark grays and browns for northern climes.

3) Regardless of what blueprints one uses, please select wood that is not treated to avoid birth defects. We used untreated oak for the outer previously and on the inside we used untreated rough sawn cedar that was weathered.

4) The inner "cells" of bat houses should have horizontal "steps" to be able to give the little ones a helping step up or down. We achieved this by using rough sawn cedar but added horizontal incisions by using a dremel tool. Others have used V gauges while others have used hardwire cloth. A few have used metal grates however this might not be a great idea as if a little bat gets his toe stuck he might not be able to chew his toe off to free himself if a galvanized grate was used.

5) Idealistically, bat houses should be mounted under the eaves at an elevation of around 25' preferably facing sw or se. Try to avoid a full southern exposure as we don’t want to cook them. The height at which a bat house is optimally installed will vary from species to species but about 20’ seems to be the minimum for bats native to our region as a 20 foot clearance underneath is required in order for them to release from their upside-down position, unfurl their wings, and to attain lift. Bats need a little "swoop" space to be able to take off, but if the area below the house is clear (no shrubbery, power lines, etc), the conventional wisdom is the higher the better.

6) Bat houses mounted in trees are virtually never occupied because bats don't like to have to negotiate branches and things when they're flying in.

7) In our area, bats will generally occupy them as fast as we can make them and install them. They are migratory and in the spring they seem to be always be on the lookout for suitable areas in which to raise their young. We have several different types of bats and the bat houses fill up quick due to loss of habitat. This being said, not all areas are like ours. One could conceivably do everything by the book and based on the species present in their area, a bat house could conceivably take several years to be occupied... if at all.

8) Bats are very tidy so one does not need to take a bat house down and clean it as one would a Martin house. This means that one does not need a pole that comes down. Bats are extremely fastidious housekeepers.

9) Never had occasion to use bat baits however I am told they were ineffective by those experimenting with the use of them.

10) I do not have a landing pad under any of our bat houses and they are being used. I'm thinking this is going to be dependent on species and a landing pad should be added to any bat house to better insure occupancy.

11) Bats do make a sizeable dent in the mosquito populations which is a bonus in areas where spraying is disallowed.

Supplement

Handout to students
Protecting Bats from Extinction
By Nick Tchankoshvili
Protecting Bats from Extinction (ActionBioscience)

article highlights

Bats have survived for millions of years but now they are declining rapidly because of:

* loss of habitat and foraging areas
* pesticides in their favorite food — insects
* extermination
* human activity such as hunting or cave exploring

Our Blueprints



Cross Section of Interior Cells