I am now in the fifth winter of my study of winter bat activity in my South Derbyshire garden. After a cold first week with a sunset temperature of -1.9°C on the 2nd, the rest of December was mild with sunset temperatures averaging 6.8°C and as high as 12°C on a couple of evenings.
Bats were on the wing on 20 nights during the month with four species/species groups recorded – common and soprano pipistrelles, Myotis bats and a single noctule pass on the 16th. Some of the Myotis bat sonograms were a good fit for Daubenton’s with others being weaker and difficult to assign.
Feeding buzzes from common or soprano pipistrelles were noted on six nights, indicating that they were finding insects on mild evenings. Social calls of common pipistrelles were recorded on nine nights; on the 23rd a common pipistrelle was social calling persistently from midnight until 3am, likely a belated attempt at attracting a female!
A single common pipistrelle recorded on the 2nd December at 6:51pm was flying in a temperature of -2.2°C, just before the snow started to fall.
The amount of pipistrelle activity recorded each December has gradually increased over the five years while there has been variation but no particular pattern to Myotis activity.
Alan Roe
Recorder
