Study type: Medical/biological study (observational study)

Bats avoid radar installations: could electromagnetic fields deter bats from colliding with wind turbines? med./bio.

By: Nicholls B, Racey PA
Published in: PLoS One 2007; 2 (10): e297
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Aim of study (acc. to author)

To test the hypothesis if radiofrequency electromagnetic irradiation exerts an aversive response in foraging bats (in the vicinity of radar installations).

Background/further details

The study was performed to test whether radiofrequency electromagnetic fields could be used as a method of preventing bats from death caused by collisions with wind turbines.
Four civil air traffic control radar stations, three military air traffic control radars and three weather radars were selected, each surrounded by heterogeneous habitat. At each radar station bat activity was recorded at three matched sites along an electromagnetic field gradient. Each radar station was surveyed three times with three different sampling points sampled on each occasion.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1–4 GHz
Exposure duration: continuous

General information

reference article: Lin JC (1990) "Auditory perception of pulsed microwave radiation" in: Gandhi OP, ed (1990) "Biological effects and medical application of electromagnetic energy" Chapter 12 Englewood Cliffs, NJ: Prentice Hall pp 275-318

Exposure 1

Main characteristics
Frequency 1–4 GHz
Type
Waveform
Exposure duration continuous
Exposure setup
Exposure source
  • radar stations at 10 different locations
Sham exposure A sham exposure was conducted.
Additional info At each radar station three different field strength categories (see exposure parameters) were monitored.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2 V/m minimum measured - E > 2 V/m near the source in a distance < 200 m d:
electric field strength 2 V/m maximum measured - E < 2 V/m between 200 m and 400 m distance from the source d:
electric field strength 0 V/m - measured - distance from the source > 400 m

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

Bat activity was significantly reduced in habitats exposed to an electromagnetic field strength of greater than 2 V/m when compared to matched sites registering electromagnetic field strength levels of zero (control sites). The reduction in bat activity was not significantly different at lower levels of electromagnetic field strength within 400 m of the radar.
The authors predict that the reduction in bat activity within habitats exposed to radiofrequency electromagnetic field irradiation may be a result of thermal induction and an increased risk of hyperthermia.

Study character:

Study funded by

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