Friday night 6th September 2013 - after heavy rain during the day ended the summer heatwave. Many insects were about after dark, especially moths but the sky had cleared and it was becoming cooler. Bats would be feeling hungry, the cooler air reminding them of autumn and hibernation.
Sometimes the moon can be too bright for bats!
But last night there was no moon visible, the sky was a deep blue and almost dark at 20.30.
Yes, the bats were indeed out hunting, very few visible in the rapidly growing darkness but the bat detector was picking them up. Loud and fast.
There were too many Common Pipistrelles to count as the signals were non-stop here at the base of the bat flyway which starts at the high pond oaks and continues down towards the river via the hedgerow and hedgerow oaks, reaching the river thickets and old river bank oaks.
Amongst the Common Pips were signals from a few Soprano Pipistrelle bats. Walking along under the trees along the river many more Pipistrelle signals were detected, including under the bridge. This new structure may well eventually attract roosting bats. Most of our local species have traditional summer roosts in the old trees with broken branches, holes, cracks and loose bark which we protect and conserve for birds, bats and hundreds of species of insects. Tidying up the trees, cutting off dead branches and removing loose bark kills bats. Although they may not be present when the work is being carried out, when they return they will find their traditional roosts destroyed. They are unlikely to find new roosts in time and may perish in the cold, having to fly long distances in the open, searching for a new roost.
Further along more Pipistrelles, then different signals - from Daubenton's bats hunting insects low over the river. A very good indicator of water quality - clean water means more aquatic insects attracting predators, fish, birds and bats.
Lower frequency signals from the sky between the tree canopy and lower around an old ivy-covered broken tree came from Noctule bats - large, strong fliers with summer roosts in old trees, they fly high in search of aerial insects. Occasionally a barn owl appears, silently hunting bats after dark when mice and voles are scarce. Bats have their animal predators but their greatest enemy is Mankind destroying their habitat.
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