Created April 2009
Last updated July2019
Eptesicus serotinus ( Schreiber 1174)
Photo Henry Stanier
Serotines are large bats with a body length of between 60 – 82mm. They weigh between 15-35g. They live for up to 19 years. They are amazingly languid bats that swoon out of their roosts
Their fur is quite long and shaggy and is a rich dark brown on the dorsal surface and paler brown underneath
Serotines produce large bomb shaped droppings with strongly tampering ends
Serotines have a characteristic syncopated call peaking at 27-30 kHz. To our ears they sound like a somewhat stoned jazz drummer. With a short call sequence they can be confused with Noctules or Leisler’s
They have a slow leisurely and agile flight 10-30mm above the ground, feed at 10-15m but will come to the ground to feed on dung beetles. Are often therefore associated with horse and cow pasture. Often feed in groups.
Serotines are one of the rarest bats in Bedfordshire. A single specimen was found in Hibernation in 2001 and in 2005-2006. several sightings of flying bats were recorded in the east of the county.
In 2007 we had a concerted hunt for serotines and by using a mixture of car and walking surveys a number of new records were obtained.2009-7 desperately seeking serotines
In August 2008 three serotines flew into a strategically placed mist net and we were able to radiotag one of the three bats which flew into it.(We were astounded to catch three bats in one instance as serotines are manouverable and capable of dodging most mist nets.
This led to us finding the first roost in Bedfordshire, despite the fact that she groomed the tag off within twenty four hours, something which we have heard reported elsewhere. They don’t so much leave their roosts as swoon out of them – and they are extremely noisy before leaving the roost. August 2009 we radio tracked a female from this roost for ten days.
Photo Jude Hirstwood
This roost was part of Caro Moosey’s PHD project which is looking at genetic diversity in serotines. In July 2011 she came back twice to try to recapture bats she had ringed the year before 13serotines2
We have gone back since to monitor bat numbers and check ring numbers
Photo Jude Hirstwood
Our favourite confirmed record was obtained by phone – a member of the public with a bat detector rang us and we were able to confirm it was a serotine from the echolocation call hear in the background.
Photo Lisa King
We have since discovered another serotine roost in mid Beds, one of the juveniles of got grounded and are picking up serotines more regularly at Stockgrove Park.
More information
http://www.bio.bris.ac.uk/research/bats/britishbats/index.htm