Some further results from the winter bat activity survey in my South Derbyshire garden. December was mild with sunset temperature averaging 8°C and not dropping below 1.8°C. Even through the night, the temperature only dropped below freezing for a few hours once, in the early hours of 22nd December. Overall, mean temperatures for the month were 1.4°C warmer than the average for the 30 year period 1991-2020 (Met Office).
Bats were on the wing on 26 nights with five species/species groups recorded during December. This is my third winter of continuous monitoring with a static detector and the first time I’ve recorded noctule or Leisler’s bat during December. Noctules are regular in the summer but previously they have disappeared after November and only reappeared in mid-March. Leisler’s bats are only occasional here even in summer, we have a small colony in bat boxes on the other side of the village. Leisler’s bats are not always easy to identify with certainty from echolocation calls but in this case there were some narrowband calls indicating that the bat was flying in the open, making identification straightforward.
Feeding buzzes from common pipistrelles were noted on several nights, indicating that they were finding insects on mild evenings. One common pipistrelle gave 4 feeding buzzes and 12 social calls within the space of 12 seconds – how’s that for multi-tasking! Most activity occurred between sunset and midnight, although a few pipistrelle passes and one noctule pass were recorded in the early hours. A common pipistrelle on 1st January was my first bat record for 2022, just 1 hour 28 minutes into the new year.
Alan Roe
Recorder
