It won’t have slipped your attention that signs of autumn are upon us, and with this changing of the season comes the change in wildlife. Most of our summer visitors have headed south, with pied flycatcher and cuckoo likely to be in southern Europe or even Africa by now, and trees are bearing fruit in time for the arrival of winter thrushes and supporting species looking to stock up for the winter, such as squirrels, mice and jay.
Good crop of bilberries this year (Photo by Gavin Chambers)
Another species group that are looking to stock up for the winter are bats. Most species have finished their breeding season and young pups (bat babies) will have become independent. For the next couple of months bats will be out trying to up their fat reserves in preparation for winter hibernation. As they are so active and nights are drawing in a little, it is a great time of year to get out and see what bats are flying around.
On Saturday I led a guided bat walk from the RSPB shop to take in the Sculpture Park and over the dam. Despite the chillier conditions we were pleased to record lots of bats and see glimpses of some of them through our thermal imaging scope. Common and soprano pipistrelles were the commonest and were often seen under the street lights, there were several daubenton’s bat feeding low over the river by the Sculpture Park and every so often we had the slapping sound of a noctule bat on the bat detectors.
Recording of a noctule bat at Lake Vyrnwy
We were also fortunate to record a few other unusual species like brown long-eared bat, bechstein’s bat (unconfirmed) and serotine bat. I hadn’t fully appreciated the musical rhythm some of these bats have, so it was amazing to hear the rhythmic beat of the noctule serotine bat on the detectors. EDIT (Nov 2019) - It turns out this recording is actually of an actively feeding noctule bat rather than a serotine.
In these cooler wetter periods, it’s great to have something else to hunt for while insects are hiding, and birds have reduced in between seasons. Some may say I’ve gone a little batty, but having enjoyed a Montgomeryshire moth event looking at the world of micro moth leaf mines recently, I’ve started to take a real interest in these fascinatingly small insect homes.
Leaf mine on beech leaf by Gavin Chambers
Micro moths are generally only several millimetres in length and a proportion of these spend part of their lifecycle feeding inside of leaves as caterpillars. Each species of moth has a plant/tree species of preference and creates different patterns within the leaf structure allowing us to identify them. Above is a leaf mine on a beech leaf which is a type of mine known as a ‘gallery’, a long narrow twisting pattern. There are only two species of micro moth that makes this kind of pattern on beech, and because this mine started at the mid-rid we know this is stigmella tityrella. The adults are rarely seen and even if they were, they are so similar to other species that they are extremely difficult to identify, making leaf mine hunting to best way of recording them.
Gavin Chambers, Warden
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