If you want to find bats: use a bat detector!
Steve Markham
Bats are small, mobile and nocturnal animals that generally go about their life unnoticed.
It was just 60 years ago that we first realized that bats shout ultrasonic sound and listen to the echo to navigate in the dark; this process has been named echolocation.
We use bat detectors to listen to the bats echo-locating (it’s the bat shouting we hear, not the echo). A bat detector is essentially an electronic gadget that converts ultrasonic sounds to sounds that are audible to us; there are essentially three ways of converting bat ultrasonic sound to be audible for humans: heterodyne, frequency-division and time-expansion. But for people who just want to enjoy finding and observing bats in the field then the heterodyne bat detector is what you need; it also happens to be the cheapest.
The bat detector is the most valuable piece of equipment for watching or studying bats and when used outdoors no bat licence is needed. With a heterodyne bat detector, and a little training, it is possible to identify most bat species and even hear what it is doing (e.g. feeding or calling to other bats). The bats go about their business undisturbed, so you are watching their natural behaviour. Best of all, using a bat detector means you will find the bat in the first place and with practice you will find other species of bat; perhaps more surprisingly they may come and see who you are!
Happy listening!
Heterodyne Bat detectors (prices inc VAT)
Steamrail HD2 (limited to 100kHz) - £55.00
NEW Magenta Bat4------------------- £59.95
Ciel Electronique CDB103 ---------- £66.50
NEW Magenta Bat5 (Digital) --------- £94.95
Ciel Electronique CDB101 (Stereo) - £99.95
NEW Batbox IIID (Digital) -------- £134.95
Ultra Sound Advice Mini-3 -------- £149.95
Pettersson D100 ------------------ £185.00
Pettersson D200 ------------------ £225.00
Magenta Bat Detector Kit (soldering required) - £35.96
Most available from Alana Ecology
(but note that these are not guaranteed to be the best prices)