A “transect” is simply an arbitrary line throughout a habitat where continuous or point-count measurements of species occupancy can be conducted. Using bat detectors on transects allow us to estimate and monitor bat abundance and/or species abundance at single locations and multiple locations throughout a habitat. By moving continuously through a habitat and recording bat calls we can be assured that each call recorded represents a different individual, since it is unlikely in the extreme that a single bat will be following us along the entire transect, or portions of a transect.
By stopping periodically on our transect line and monitoring for a pre-determined amount of time, we can cover a lot of ground and perhaps intercept bats and record longer file sequences that could be more useful for species ID.
The tools we might select to accomplish this mission is a little different than a straightforward active or passive detector. We want a high quality microphone system as always to maximize the chances for species ID. Because the microphone is often moving during the survey, an omnidirectional mic response may be desirable to record longer call sequences as the bat remains in the "bubble" of moving reception. A live display is useful to engage users on what otherwise may be a tedious, uneventful monitoring session. Finally, the whole point of transects is to log bat activity over a large geographic area, so some sort of software solution for visualizing transect data is helpful.
Why the AR125FG?
What do you need?
BCM's Comparison Chart for Acoustic Transects
A note about automatic classification of bat calls: Some manufacturers are incorporating species ID into their devices. While this is an amazingly fun thing to watch in real time. the reality is often the species ID can be flat out wrong. If you as a user choose to append automatically classified names to the data and/or maps, you and anyone that data is shared with should be prepared to accept some degree of error. For professional use, BCM strongly suggests all auto-classifications be expertly reviewed using professional level software before accepting any data results.
See also: BCM's top pick for:
Conceived at the April 1, 2013 Western Bat Working Group Meeting, BCM received the first two prototype miniMic devices just a few weeks later in time for a full summer of testing. The D500X is a USB driven full spectrum ultrasound microphone intended for live view active monitoring, mobile transects, and short term unattended (passive) monitoring of bat and other high frequency animal calls. The miniMIC is specifically designed for applications such as bat recording and vocalization analysis where wide spatial coverage and a wide ultrasonic frequency range are desired. It employs low noise circuitry along with 16-bit digital converters to achieve high sensitivity along with a large dynamic range. It is capable of detecting bats at a distances up to one hundred and forty feet.
General MiniMIC Features:
MiniMIC is better suited for: