Norfolk Wildlife Trust Conservation Officer Helen Baczkowska searches for the elusive barbastelle bat in the Claylands.
On a warm summer evening in the Norfolk Claylands, I am standing in a meadow with my friend Mick. He has his bat detector ready and as he presses a button, the black box emits a chugging sound at around 45 kHz. 'Pipistrelle', says Mick. This is Britain's smallest bat, no bigger than my thumb, and I spot it, for a moment, twisting as it hunts moths across the meadow. I say that I am sure I could hear bats when I was a child and Mick tells me this was probably the social calls of pipistrelles. Sadly, human hearing diminishes as we age and I can now no longer hear the high-pitched squeaks and instead have to rely on the detector to pick up the echo location the bats use as they hunt and navigate at night.
Common pipistrelle by Tom Marshall
As the evening darkens, there are a couple more pipistrelles - possibly the same one returning - then a noctule flies high along the hedge before diving as it closes in on its prey. I am a novice in the world of bats and excited to be here, learning about creatures we usually only glimpse as flitting shadows in the dusk.
We are hoping for a barbastelle, Britain's rarest bat and recorded on a few sites in the Claylands. These are medium-sized bats, around four or five centimetres long and with broad wings. Close up, their noses are pug-shaped, their ears wide and although the wings and head are mostly black, the body is tinged with ginger-brown hairs. If we had been lucky enough to pick one up on the detector, it would have been a series of short clicks like castanets and slower pulses at around 32 kHz. In summer up to 20 females gather together in maternity roosts, often in the darkest parts of woodland, in cracks and old trees. When the young are ready to fly, at around three weeks old, they follow their mothers out of the woods to hunt for moths and lacewings along hedges and over grassland. The males are more solitary creatures in summer, moving frequently between daytime roosts, from joints in old timber barns to flaking bark on dead branches or trees. In winter the bats will hibernate in similar spots, but they are hardy compared to other species and occasionally move between roosts on mild days.
Bat surveyor by Tom Marshall
As it grows dark, I can no longer see the bats, only hear when the detector picks up their sounds. I try to imagine the landscape as they see or more accurately hear it at night. There seems so much that is vital for them, especially grasslands where moths and other insects flying thrive, as well as hedges, woodlands, commons and churchyards, wildlife gardens, trees with dead or dying branches, playing fields and ponds. Most of all, I realise it is having a landscape where these habitats not only exist, but are connected, allowing the bats to move between feeding sites and roosts.
Header image: Barbastelle bat by Mnolf