Application purpose:
Collecting data on bat flight events, flight lines, flight behaviour and roost emergence/re-entry.
Thermal imaging can assist in understanding how bats are using buildings and the surrounding landscape enabling the potential impacts of planned changes to be suitably assessed. Thermal imaging has a higher detection rate than other visual and acoustic methods and is particularly useful where long range detection is required.
Using the table below, select the most appropriate camera model based on the following application level descriptions. Please also consider any limiting factors that may apply.
- Basic Applications include: Internal surveys to observe roost emergence/re-entry locations at distances up to 10 meters.
- Intermediate Applications include: Internal and external surveys to observe flight lines and roost emergence/re-entry locations at distances up to 13 meters. For greater image clarity assisting with species identification, it is recommended that the target distance is within 7 meters.
- Advanced Applications include: Basic and Intermediate applications requiring higher quality images and video for presentation and analysis purposes, and/or where the target distances are greater than those discussed above.
Model |
Basic |
Intermediate |
Advanced |
|---|---|---|---|
FLIR E4 |
Not Recommended | Not Recommended | Not Recommended |
FLIR E5 |
Not Recommended | Not Recommended | Not Recommended |
FLIR E6 |
Not Recommended | Not Recommended | Not Recommended |
FLIR E8 |
Not Recommended | Not Recommended | Not Recommended |
FLIR E53 |
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FLIR E54 |
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FLIR E60* |
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FLIR E75* |
|
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FLIR T540* |
|
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FLIR T640* |
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FLIR T660* |
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FLIR T865* |
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FLIR T1020* |
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FLIR T1030sc* |
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*Used with standard 24-28° lenses.
Preparation/Environmental Conditions
The majority of bat surveys should be carried out between April and October at night/early hours of the morning when the bats are most active. The weather conditions can have a significant effect on the efficacy of thermal imaging. Hot/humid nights will reduce the temperature difference between the bats and the background ambient making it harder for the cameras to ‘see’ them. Similarly, cameras should not be used during periods of precipitation (rainy or foggy conditions) as this will attenuate the infrared emitted from the bats effectively making them invisible to thermal imaging cameras.
Limiting Factors to be considered
Distance from, and sizes of the target are the most limiting factors to be considered when selecting a suitable thermal imaging camera for this application. Cameras with higher pixel resolutions and low spatial resolutions (IFOV) will enable smaller targets to be observed at greater distances. In circumstances where distances are likely to be greater than those discussed above, consideration should be given to selecting an increased specification camera which will have a greater chance of success.
Cameras with an adjustable focus are extremely important for this application to ensure image clarity, particularly at greater distances. We would not recommend the use of thermal cameras with a fixed focus lens i.e. FLIR E4, E5, E6 or E8.
The table below list the range of cameras together with the estimated maximum distances to identify the presence of actively moving bats:
Model |
Maximum Distance |
FLIR E40* |
<10 metres |
FLIR E53* |
<10 metres |
FLIR E60* |
<13 metres |
FLIR E75* |
<13 metres |
FLIR T460* |
<13 metres |
FLIR T530* |
<13 metres |
FLIR T540* |
<19 metres |
FLIR T640* |
<26 metres |
FLIR T660* |
<26 metres |
FLIR T1030sc* |
<37 metres |
*Used with standard 24-28° lenses.
Please note that the thermal imaging camera selection guidance above is intended as a guide only, Red Current Ltd will not be held accountable where the desired results do not meet preconceived expectations.
