Bat Surveys

Bats in Britain comprise a diverse family, with 18 species calling this island nation home. From the tiny pipistrelles, barely weighing a coin, to the larger noctules that wing through the night with their impressive wingspans, each one holds a significant place in the ecological tapestry. They navigate their nocturnal world with an uncanny precision, their echolocation allowing them to trace out insect highways in the darkness, pinpointing their prey with startling accuracy.

Bats are fascinating animals, and are the only flying mammal. The presence of bat species can tell us a lot about local habitats and the health of our land. They can also be effective indicator species; the change of diversity and abundance of many bat species can reflect the wider change of the local environment and other species groups, such as insects that they prey on:

  1. Indicators of wider environmental change: Bats are sensitive to changes in their environment, making them excellent indicators species. They are particularly susceptible to changes in land use, such as deforestation and urbanisation, as well as to pollution and climate change. A decline in bat populations can often signal broader environmental problems.
  2. Indicators and controllers of insect populations: Many bat species are insectivores, consuming vast quantities of insects, including many pests that can damage crops and forests. By controlling insect populations, bats contribute to the health and productivity of ecosystems and agriculture.

The diet of British bats primarily consists of insects, many of which are considered pests. Their ceaseless insect hunting plays a crucial role in controlling pest populations naturally, contributing significantly to maintaining a healthy ecosystem. Moreover, it assists in agricultural practices by reducing the need for chemical pesticides, safeguarding crop health, and by extension, our health.

Monitoring Bats

It is crucial to support initiatives aimed at conserving and enhancing bat habitats and populations in Britain. Their activities, including roosting, foraging, and breeding, are contingent on the availability of specific habitats. Consequently, any changes to these habitats—due to human interference, pollution, or climate change—may disrupt bat populations, leading to changes in their distribution or numbers. Monitoring bat species are therefore crucial to helping us understand our land and environment.

Bat monitoring involves multiple methods, each designed to provide specific insights into bat behaviour, population size, distribution, and health.

Traditional methods include “Capture & Release” methods and Roost Surveys; inspecting known or potential roosting sites can provide valuable information about bat species, population size, and roosting habits. This can involve direct observation (for instance, watching bats emerge from a roost at dusk), as well as indirect methods like looking for bat droppings or feeding remains.

Bioacoustic monitoring (also known as acoustic monitoring) has been extensively to monitor bat activity in the field. Since bats use echolocation for navigation and hunting, their ultrasonic vocalisations provide valuable insights into their diversity, species activities, and distribution.

The two primary tools for acoustic monitoring for bats are handheld recording devices and passive recording devices. Handheld bat detectors translate high-frequency echolocation calls into an audible sound range for humans, enabling field identification on the move. Passive recording devices are left out in the field to record bat calls over extended periods, maximising the recording time for species identification.

Bioacoustic Monitoring

At Carbon Rewild, we deliver bioacoustic monitoring using passive recording devices. By combining advanced recording technology with pioneering classification tools and techniques, it can provide valuable insights into the behaviour, distribution, and abundance of bat species, and help to inform conservation efforts and protect bat populations. 

  1. Non-invasive: Passive recording devices are non-invasive and cause minimal disturbance to bats. They simply record the ultrasonic sounds that bats naturally produce, without the need for following, capturing or tagging the bats.
  2. Repeatable: By monitoring the same location, repeat surveys can be conducted to monitor change in bat activity and species richness.
  3. Scalable: Because passive recording devices can be left unattended, it’s possible to use multiple units to cover a larger area. This can provide information about bat activity across a landscape, which is useful for understanding population distributions, habitats, and migration patterns.
  4. Cost-effective: Bioacoustic monitoring can be a cost-effective way to study bat populations, and the costs scale with the size of land based on the number of recording devices required.
  5. Long-term monitoring: Bioacoustic monitoring can be used to monitor bat diversity, distribution, and activity over long periods of time, allowing you to track changes in populations and study the effects of environmental factors on bird behaviour and distribution. Monitoring across multiple months during summer, when they are most active, can give us additional insights into their behaviour and how they are impact by external conditions.
  6. Easy set up: Simply find a suitable monitoring location, turn the device on and let it do the work!

Making a Plan

Whether you’re planning a new development, starting conservation work, or expecting other changes in the environment, it’s a good idea to establish a repeatable way to survey bats. By establishing a robust survey process, it can be repeated in future years to monitor species diversity, behaviour and population change.

Traditional survey techniques can also be used alongside bioacoustic monitoring to verify the presence of species, and provide even greater insights into bats.

Interested in monitoring or want to have a quick chat to learn more? Please get in touch with us here, or select the link below to see our services.