Halloween Bat Walk

 A very belated Happy Halloween!

On the night of Halloween, I joined a bat walk with the Conservation and Wildlife Society (CAWS), where we walked around the lake on campus, looking (and listening!) out for bats, including using bat detectors. Unfortunately, we failed to find any bats :( although it was very interesting to find out about the trees in which they roost and their preferred hunting grounds. It was also very nice to see the campus at night, especially on a suitably atmospheric Halloween!


Daubenton's bats

One of the many species of bat present on the UEA campus is the Daubenton's bat, and is one of the species I have managed to see on previous night-time walks, especially near the river - these vats are renowned for their use of watery habitats as hunting grounds. For the remainder of this post, I'd like to explore the biology and ecology of these species further.

Daubenton's bats (Myotis daubentonii) is a widespread bat in the British Isles, with the exception of northwest Scotland. It is on the smaller side, weighing between just 7 and 12g! 

As I mentioned, their preferred habitat is near freshwater, such as areas of grassland and woodland near lakes and rivers - hence why they can be found on UEA's campus! They use these habitats to hunt various small fly species such as mayflies from just above (or even pluck them from) the water surface. As with all bats, they use echolocation to locate their prey - and the high-pitched noises they emit during this hunting process mean we can detect and identify them. Although we sadly didn't pick any up during our bat walk, Daubenton's bats emit sounds between 35 and 85 kHz, and would sound like machine gun fire on the bat detector!

One of the reasons why we may not have seen these bats (and others) on Halloween is that it may have been too late in the season, with bats starting to enter their winter roosts (caves, mines and other underground tunnels) to hibernate from October. In contrast, during the summer, their colonies are often found under tunnels and bridges near water, as well as temporary night roosts being located near hunting grounds, such as one of the trees we saw on our bat walk. Following mating in autumn, during late spring, females also form maternity colonies, where they give birth to just one young in early summer.

Although the Daubenton's bat is classified as Least Concern both globally and nationally, there are several issues which could affect its population, including primarily habitat loss. This includes the loss of roosts, for example through the removal of roost trees, the loss of feeding areas and their prey, such as the degradation of our waterways through pollution, and the fragmentation of all these habitats, where roads and other human structures disrupt their ability to navigate between roosts and hunting areas. This all makes the protection of existing habitat for Daubenton's bats, such as our campus, very important, to prevent them making a sudden, scary and spooky disappearance fit for Halloween.

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