The work around Greenmoor Ponds by WCG volunteers has allowed us to consider how other animals rely on this small oasis, shaping and guiding our conservation efforts.
Over the last couple of years we have been acoustically monitoring the ponds and surrounding area for bats (and other creatures), and we have recorded nine species of bat foraging across the local landscape.
The abundance of broadleaved woodland, mixed pasture and a water source means that bats are coming in to forage on emerging insects and, more importantly, getting a drink, vital during this dry weather. We have also found that gardens are playing a key role where people have created wildlife friendly areas, night scented flowers being perfect for attracting pollinators and bats in to forage.
One visitor, possibly our rarest and least understood British mammal, is the Barbastelle Bat. The Chiltern Hills looks to be a significant stronghold for this species and we are getting consistent data of foraging activity. This bat species is known to travel up to 20km in a night; they emerge at dusk and stay within the shadowy woodland until complete darkness before venturing out into the night following tree lines, hedgerows, and watercourses to their foraging grounds. Interestingly, the phrase ‘as blind as a bat’ is misleading as bats actually have pretty good eyesight and will use a mixture of vision and echolocation to navigate and hunt. The Barbastelle often uses stealth tactics to catch moths, some of which can hear the approach of bats from their echolocation calls so take avoiding action and dive for cover. The Barbastelle will send a ground oriented call from its mouth to establish the proximity of objects and features for navigation, and will then use a much quieter echolocation call projected forwards from its nose so the moths don’t hear it coming until it’s too late. These calls often alternate in sequence making this bat one of the easiest to identify from sound recording files.
At the end of a hunting foray they will often fly directly back to their roost indicating that they possess good directional senses. Barbastelle’s often change roosts every few days to avoid predators.
The most numerous bats in Woodcote are Common and Soprano Pipistrelle’s. Weighing just 4.5g they can eat up to a third of their bodyweight in one night, which equates to approximately 3,000 gnats or mosquitos, food for thought when sitting outside in the evening!
We have also recorded the rare and migratory Nathusius Pipistrelle that arrives from Eastern Europe in the autumn after crossing the North Sea where radio tracking has shown it sometimes takes the bats over five hours flying over open water before they make landfall. The longest recorded journey was from a ringed bat in Hounslow that travelled back to Russia, a journey of 2,018 km.
At the other end of the scale Woodcote has an important population of Serotine Bats, this is one of our largest species in the UK that lives mainly in buildings and weighs up to 35g with a wingspan of 380mm. Specializing in chafer beetles it is a very rare bat confined to the south of England and Wales. They regularly turn up at Greenmoor Ponds and forage for a while before moving on to other areas. They are known to stay local to their roost but sometimes travel up to 6 km in a night.
August is a peak time of bat activity; their young, called pups, will have been weaned and are learning to fly, often following their mother from roost to roost and then on to hibernation sites to learn these locations for when the weather turns cold. During this time some pups can get disorientated or lost, or be victims of roost disturbance or destruction.
There is a network of carers who work tirelessly to re-unite bat pups with their mothers or rear and rehabilitate them with a view to releasing back to the wild. If a pup gets separated from its mother it is possible to re-unite them within 36 hours of being found. If the roost can be located the pup is put on a heat pad and monitored for the evening while the bats emerge and re-enter the roost. Often the pup will hear the echolocation calls and cry out, the adults will come down to investigate and, if the mother is present, she will land, feed the baby and carry it back to the roost.
Why make all the effort – three hourly feeds, special diets, moving the pups between carers to help maintain the focus and attention? The reason, a mix of love and admiration for this intriguing, and often misunderstood animal and recognition of how vulnerable and under threat these species are to human activity.
Bats in the UK are solely insectivorous. The mother will have only one pup a year – and that’s on a good year. The previous two summers with wet springs have meant that insect numbers were low leading to a reduced birth rate with many mothers not coming into condition.
Bats are long lived and are a key biodiversity indicator – suitable landscape creates the right environment for everything and everyone to thrive. With our help they can get through these difficult years.
If you come across a grounded bat or one hanging on a wall outside in daylight, it is in a desperate situation. The Bat Conservation Trust have a helpline and excellent website giving guidance of where to get help and what to do, please explore the links below.
Bat Conservation Trust Helpline
What to do if you find a grounded bat
Further information on the Nathusius Pipistrelle study of migration
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Article originally published in the August 2025 edition of the Woodcote Correspondent