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Home > Product FAQ

Bat Echolocation and Bat Detectors

What exactly is a Bat Detector?
A Bat Detector is a simple, handheld device that listens to the frequencies that bats use to hunt and find their way at night. It converts these frequencies to tones and clicks that humans can hear. Think of it as translator. Most Bat Detectors are the size of a pack of cigarettes and have a special microphone that picks up the echolocation calls of bats.

How Easy is the Belfry Bat Detector to Use?

It is so simple and easy anyone can use the Belfry Bat Detector! Follow these instructions:

1. Get out your Belfry Bat Detector.

2. Turn it on.

3. Listen.

4. It's just that easy.

What do bats sound like on a Bat Detector?

The answer to this question depends on the exact species of bat in your area, but basically you will hear a series of clicks, tocks and smacks that vary in rhythm, duration and structure. You will hear the ever present and amazing "feeding buzz" as a bat closes in on a flying insect and finally devours it. High intensity bat calls will be heard as small screams or chirps. Bat calls vary greatly and there is much information "hidden" in these short burst of sound energy. Using a personal computer (PC) with a bat detector allows you to record and then "slow down" these bats calls. Click here to listen to a small brown bat recorded on a laptop PC using our Belfry Bat Detector with audio out jack.

Where is the best place to use a Bat Detector?

Bats are usually found where there are flying insects. Wooded areas and bodies of freshwater are excellent places to hear bats. You may hear many bats at one time. You never know where you may find bats. Where I live, there are some trees, but lots of blacktop and concrete. I often see bats flying by at night. It is surprising the places bats turn up and the only way to know is to go out looking and listening for them.

When are bats most active?

Bats are most active after it gets dark. I have found that about 3 hours after sunset to about 6 hours after sunset offers the greatest activity. However, going out to find and listen to bats just 15 to 45 minutes after sunset allows you to still see them against the early night sky.

Seasonwise, you won't hear bats during the winter if you live in a colder area. Bats hibernate during the winter and are active during the Spring, Summer and very early Fall. If you are lucky enough to live in a warmer area with mild winters, you'll find bats are active all year. No matter where you live on colder days, when the temperature is around 45 degrees farenheit, bats will not fly at all.

Will using a Bat Detector attract bats to me?

No. A Bat Detector is simply a listening device. It works very much the same way a portable radio does, except instead of listening to radio stations it listens to bats. Any bats you listen to will ignore you and go about their normal routine.

Does using a Bat Detector upset bats in any way?

No. Unfortunately, there are many human activities that are reducing bat populations and destroying their habitats, but using a Bat Detector is not one of them.

Where do I get a Bat Detector?

Bat Conservation International sells units for about $250.

I build Belfry Bat Detectors to order for $64.95. Each unit is fully functional and ready to go. Please click here to see more information on our products for bat enthusiasts.

Why is your Belfry Bat Detector design better than the other Bat Detectors?

Most other Bat Detectors I have seen require the user to "tune" the detector to the proper frequency and then you can only hear that one frequency. Different bats use different frequencies, so you could tune one of these detectors to 40 khz and completely miss a bat flying around using 25 khz!!! Furthermore, the same bat can use a wide range of frequencies in its search for insects.

My design converts practically the entire frequency range that bats use, about 20 to 100 khz. This way, you don't need to fuss with knobs. Simply turn the unit on and sit back while listening to all the bats in your area. The unit contains a small speaker so many people can listen at once and it runs for many hours on a 9 volt battery.

Can I record bat calls using your Belfry Bat Detector?

Yes. We offer an option for $10 that will add a 1/8 inch monaural audio out jack. This is a high impedance output that may be connected to a tape recorder, a laptop PC (personal computer) with soundcard or even an amplifier for large group demonstrations.

How can I use a PC to record bat calls with your detector?

Just plug a cable into the Belfry Bat Detector's audio out jack and the other end to the soundcard on your PC. Then, you'll need a software package to capture the calls. Click here to dowloand a free, shareware sound analysis program, called Spectrogram, that I find very useful. Click your Browser's BACK button to return here when finished downloading.

To learn more about how we use Spectrogram and to see some sample bat calls prcoessed using this free shareware, click here.

What is Echolocation?

Bats are truly amazing creatures. Most people know exactly what a bat is and what it looks like, yet there are many myths surrounding bats that simply aren't true. Bats are not blind, they are not flying rodents, they won't get tangled in your hair and usually they do not bother people. However, they do have an amazing ability that scientists and the military have been trying to uncover for more than 100 years. They can see using sound - this is known as echolocation or biosonar.

Even though bats have strong eyesight, they are nocturnal creatures that spend their waking hours flying at night in almost total darkness. They are easily able to avoid obstacles and feed on insects using their biosonar. A bat can readily eat 1,000 mosquitoes in about an hour using echolocation.

Bats use their biosonar in a sound or frequency range that humans cannot hear. Human hearing spans from about 200 hertz (or 200 cycles per second) to 20,000 hertz (or 20,000 cycles per second). Bats can hear well into the ultrasonic range or up to roughly 200,000 hertz. Their biosonar operates from about 25,000 to 100,000 hertz, abbreviated as 25 to 100 kilohertz or khz (thousand hertz).

It may be a good thing that we cannot hear bats because their biosonar can be quite loud. Echolocation calls can range from 100 decibels (or db) to about 60 db. 100 db is approximately equivalent to a smoke detector alarm and 60 db is about the sound level of a human conversation. If you live in the USA, you most likely have little brown bats and big brown bats in your area. These are examples of bats that are loud, in the 100 db range, and use a frequency of about 25 to 35 khz.