The recent uplift in temperatures has begun to transform life in the commons, even though the signs are often so very small, the effect is a seasonal shift, the stirrings of spring.
Entering the commons by way of the tunnel car park, the first signs only became apparent when gazing toward the setting sun. Illuminated in the watery winter rays were insects, tiny and fragile winged insects, possibly mayflies, bobbing up and down on invisible threads about a meter and a half above ground. These dancing flies seemed suspended along the line of the sunlight and when approached become still, disappearing from view, onto the nearest leaf.
Lichen and moss covering branches on the avenue of oak trees were responding to the extra light adding a faint green tinge to the lattice of budding branches overhead. A tour around the muddy edges of the pond and investigation into the submerged clumps of grasses, revealed no signs of frog spawn, however a little distance apart were stands of hazel flushed with catkins.
On the approach to the tunnel car park in the fading light, a flying creature, not a bird but a bat, a very small bat dipped and swooped across a natural amphitheater, the aerial space between the crowns of three towering oaks.
Its height and rapid flight movements made identification difficult but recognising and noting particular features helps to guide later identification in reference books. The reference guide, RSPB’s Wildlife of Britain, lists 5 species of bats: the brown long-eared bat, the common pipistrelle, Daubenton’s bat, the noctule bat and the serotine bat.
According to the information on geographic distribution, all 5 bats can be found in the area of Bookham Commons. By process of elimination the description of the noctule and serotine bats are too large in body and wing span to qualify, and judging by the silhouette the absence of long ears eliminates the brown long-eared bat. The common pipistrelle is described as having a somewhat jerky flight pattern which again, does not fit, leaving the possibility of Daubenton’s bat.
Interestingly, Daubenton’s bat favours open wooded areas, so that’s a tick for habitat type and, the clincher, ‘roosts in cracks in trees, and buildings and under bridges.’ Nearby, less than 30 meters from the site where the bat was spotted lay a potential roosting site in the railway tunnel, underneath the tunnel car park. There is the possibility that the sighting could have been Daubenton’s bat, but as every good naturalist knows, a positive identification of a species requires rigor and scientific investigation technique.
Even though positive identification is not always successful, there is a pleasant satisfaction in bearing witness to the ecological system at work through the changing seasons, the rise in temperatures allowing the insects to hatch, the insectivores responding to the food source and the cycle of life continues.