6
indoor meeting. These included Pipistrelle
(Pipistrellus pipistre1lus) which has not
been found since in the deneholes and also
Whiskered bat (Myotis mystacinus) — a species
found only twice since then.
The first county record of Hairy-armed bat
(later re-named Leisler's, Nyctalus leisleri)
occurred at the turn of the century and the
third record of Serotine - an individual shot
at Pitsea and displayed at a Field Club
meeting, also occurred at this time.
The next date of note is 1949, when the second
Leisler's bat was found. At this time
K. Burtsal was ringing bats in the Saffron
Walden area and he caught and ringed 2 indi-
viduals. Unfortunately, most of his records
have not survived. The 1960's saw further
occasional forays down the deneholes, but only
3 species were found - Daubenton's (Myotis
daubentoni), Natterer's (Myotis nattereri)
and Brown Long-Eared (Plecorus auritus). At
this time the vaults of Colchester castle also
held these 3 species and a ringing programme
was undertaken. I believe this site has since
been made unsuitable for hibernating bats. '
Then, in 1975, the third record of Leisler's
occurred; this time an individual found dead
at Witham. The corpse is now at Colchester
museum.
In 19B0, I started a new survey, initially
recording bats with a bat detector and also by-
using mist nets at feeding sites such as reser-
voirs and gravel pits. The commonest bat in
Essex is the Pipistrelle and probably 85-90% of
Essex bats are Pipistrelles. They breed in