To test the hypothesis if an electromagnetic signal from a small portable radar can exert an aversive response in foraging bats and aerial insects.
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. From June to September 2007 bat activity was compared at 20 foraging sites in northeast Scotland during experimental trials (radar switched on) and control trials (no radar signal). The order of trials were alternated between nights.
From July to September 2008 aerial insects at 16 of these sites were also sampled.
| Exposure | Parameters |
|---|---|
Exposure 1:
Modulation type:
pulsed
Exposure duration:
continuous for 20 hr (bat activity) or 16 hr (insect count)
|
|
Exposure 2:
Modulation type:
pulsed
Exposure duration:
continuous for 20 hr (bat activity) or 16 hr (insect count)
|
|
Exposure 3:
Modulation type:
pulsed
Exposure duration:
continuous for 18 hr (bat activity) or 16 hr (insect count)
|
|
| Frequency |
|
|---|---|
| Type | |
| Exposure duration | continuous for 20 hr (bat activity) or 16 hr (insect count) |
| Modulation type | pulsed |
|---|---|
| Pulse width | 0.08 µs |
| Duty cycle | 1.68 % |
| Repetition frequency | 2,100 Hz |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 6 kW | peak value | - | - | - |
| electric field strength | 5.58 V/m | peak value | measured | - | at a distance of 10 m |
| electric field strength | 5.11 V/m | peak value | measured | - | at a distance of 20 m |
| electric field strength | 3.79 V/m | peak value | measured | - | at a distance of 30 m |
| Frequency |
|
|---|---|
| Type | |
| Exposure duration | continuous for 20 hr (bat activity) or 16 hr (insect count) |
| Modulation type | pulsed |
|---|---|
| Pulse width | 0.08 µs |
| Duty cycle | 1.68 % |
| Repetition frequency | 2,100 Hz |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 6 kW | peak value | - | - | - |
| electric field strength | 26.24 V/m | peak value | measured | - | at a distance of 10 m |
| electric field strength | 22.99 V/m | peak value | measured | - | at a distance of 20 m |
| electric field strength | 20.25 V/m | peak value | measured | - | at a distance of 30 m |
| Frequency |
|
|---|---|
| Type | |
| Exposure duration | continuous for 18 hr (bat activity) or 16 hr (insect count) |
| Modulation type | pulsed |
|---|---|
| Pulse width | 0.3 µs |
| Duty cycle | 3.6 % |
| Repetition frequency | 1,200 Hz |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 6 kW | peak value | - | - | - |
| electric field strength | 25.52 V/m | peak value | measured | - | at a distance of 10 m |
| electric field strength | 18.68 V/m | peak value | measured | - | at a distance of 20 m |
| electric field strength | 17.67 V/m | peak value | measured | - | at a distance of 30 m |
Bat activity and foraging effort were significantly reduced during experimental trials when the radar antenna was fixed to produce an unidirectional signal therefore maximising exposure of foraging bats to the radar beam. However, although bat activity was significantly reduced during experimental trials, the radar had no significant effect on the abundance of insects captured by the traps.
However, although bat activity was significantly reduced substantial numbers of bats continued to forage within the radar beam. It is possible that only a particular combination of wavelength, pulse repetition rate and power output may provoke a reaction.
This website uses cookies to provide you the best browsing experience. By continuing to use this website you accept our use of cookies.
