6
Each bat species (16 in Britain) has its own
preferred type of roost. Some are confined to
trees whereas others, notably the Pipistrelle
favour hollow walls, roof spaces and crannies
behind weather-boarding, hanging tiles or above
soffits. There is always at least one exit hole
which may be some distance from where the bats
actually roost during the day. It is my
experience in Essex that individual roosts are
not occupied throughout the year. Each group of
Pipistrelles seems to have about 6 houses that
they commute between during May to early September
During mid-June they gather in one place which
is to be used as a breeding colony. At this
stage tell-tale signs are droppings (which are
small and mouselike) on paths, beneath gables,
on window-sills, beneath hanging tiles or stuck
to windows. There will also be bird-like
squeaking prior to emergence. Bats do not make
nests, they cling onto the insides of cavity
walls and give birth to their young. At each
breeding roost, bats may have gathered from
several square miles and these roosts are vital
for their future. Those species which hibernate
in caves can be conserved during the winter, with
Pipistrelles the roosts must remain undisturbed.
when weaning is complete the adult females
leave, followed later by the young. Most roosts
are deserted by mid-August although small groups
will often turn up at other houses in the area
at this time, although they only seem to stay
for a few days.
Since 1981, I have been doing a survey on bats
in Essex and the priorities have been two-fold.
Firstly to try and identify which species occur
in Essex and then map their distribution, and
secondly to follow up complaints and enquiries
concerning "bats in houses" to present the bats
point of view. A typical complaint occurs in