A thermal imaging camera captures and displays the thermal radiation emitted by objects. Unlike traditional cameras that rely on visible light, thermal imaging cameras detect the infrared radiation emitted by objects based on their temperature.
Thermal imaging cameras use a sensor called a microbolometer that can detect and measure the heat signatures emitted by objects in the form of infrared radiation. The sensor converts the infrared radiation into electrical signals, which are then processed and translated into a visual representation, where different colours or shades represent variations in temperature. Thermal imaging cameras are increasingly being utilised in wildlife conservation due to their ability to detect the heat signatures emitted by animals.
Pulsar Helion 2 XP50 thermal imaging monocular
Thermal imaging cameras enable surveyors to detect and observe bats by capturing their heat signatures, allowing for the identification of roosting locations and specific points of entry and exit for bats, providing valuable insights into their behaviour and habitat use. This technology excels during dusk, dawn, and night-time surveys when wildlife is more challenging to observe with the naked eye.
Thermal images provide a unique visual perspective that complements other bat survey methods such as acoustic monitoring. Many thermal imaging cameras also have recording capabilities, providing visual evidence to support survey work.
When utilising thermal imaging cameras for bat surveys, it is important to be aware of several common challenges and limitations. These include the need for proper training to accurately interpret thermal imagery, the inability of thermal imagers to provide sufficient detail to identify bats to species level, difficulties in surveying densely vegetated areas or complex landscapes, and the potential for false positives due to other heat-emitting sources. Being aware of these limitations helps surveyors understand the scope and reliability of using thermal imaging cameras for bat surveys, encouraging the use of complementary survey methods for a more comprehensive assessment of bat populations and behaviours.
Atmospheric conditions can also impact the performance of thermal imaging cameras. Factors such as humidity, fog and rain can diminish the clarity and range of the camera’s imaging capabilities. A thermal imaging camera with higher thermal sensitivity will maintain superior image clarity and continue to operate effectively over longer distances, even in more challenging atmospheric conditions.
Thermal image of a bat box showing heat (bright white) in the top of the box
There is a broad and ever-expanding range of thermal imagers available, with prices ranging from several hundred pounds to thousands. Higher-end thermal imagers offer enhanced temperature differentiation and perform more effectively at longer distances, making them versatile and more reliable in various atmospheric conditions. When it comes to bat surveys, it is crucial for a thermal imager to possess adequate sensitivity for the specific survey requirements. The best approach to determine suitability is by examining the specifications that describe image clarity, such as thermal sensitivity and thermal sensor resolution.
We’ve produced a guide to choosing a thermal imaging camera for bat surveys, breaking down the key specifications to consider and what they mean, as well as recommending several Pulsar thermal imaging camera models that we’ve put to the test in the field.
Thermal imaging is a reliable method for determining the locations where bats roost in trees and man-made structures. It provides clear proof of bats roosting and specific locations where they enter and exit.
Thermal imagers can only be used to detect and recognise bats, they cannot be used to identify bats to species level, therefore they must be used in tandem with acoustic recording equipment to identify bat species.
When using thermal imaging cameras for bat surveys, it is crucial to comply with legal regulations specific to your country or region. This may involve obtaining licenses, permits and/or permissions for conducting bat surveys or using thermal imaging equipment. Additionally, it is important to respect privacy and data protection laws as thermal imaging cameras may inadvertently capture thermal profiles of other organisms or objects. Minimising disturbance to bats and their habitats is paramount, ensuring that survey methods, including the use of thermal cameras, do not harm or disrupt the bats or their natural behaviour. Using appropriate and properly calibrated equipment is vital to ensure accurate data collection. Seeking guidance from local authorities, bat conservation organisations, or experienced professionals can help navigate the specific legal and ethical considerations for conducting bat surveys using thermal imaging cameras.
Dr Kayleigh Fawcett has published ‘Thermal Imaging: Bat Survey Guidelines (2021)’, in association with the Bat Conservation Trust. We recommend reviewing this comprehensive document to support your choice in suitable thermal imaging equipment for your surveying needs. The Bat Conservation Trust also published an interim guidance note on night vision aids for bat surveys in 2022. We anticipate that more guidance on best practice is imminent, given the increased interest and uptake in thermal imaging for bat surveys.
Yes, thermal imaging cameras can be used in conjunction with other survey methods, including acoustic monitoring, to monitor bats. While acoustic monitoring is commonly used to detect and identify bat species by recording their ultrasonic echolocation calls, thermal imaging can provide additional information about bat presence, behaviour, and roosting locations. Used in tandem with traditional recording methods, thermal imaging adds new layers of information and extra detail to bat surveys.
Learn more about thermal imaging camera specifications in our standalone guide, covering topics that include: detection, recognition and identification range, sensor resolution, thermal sensitivity, pixel pitch and more.
