A conservation success in Essex!
The bunkers are around 2m high, 15m long and entered by a front door.
Inside, 60 years after seeing active service, the concrete sections are
still intact with very few crevices available for hibernating bats.
To overcome this, a number of innovative measures have been taken to make
these sites more attractive for bats.
Specially-manufactured bat bricks have been attached to the ceilings of
the bunkers and canvas material has been draped over coat hangers to
create crevices favoured by brown long-eared bats.
Tree trunks with bat-sized slots have been leant against walls and these
have been used by up to ten Natterer’s bats, with a maximum of four in one crevice.
Bats are usually to be found in the crevices provided, but occasionally
an individual such as this Natterer’s bat is found hibernating in the open.
The bat bricks have proved extremely successful with up to four bats being
found in a single brick. In this case, a single Natterer’s bat was found.
This series of bunkers is of most importance during very cold weather
when alternative hibernation sites become unsuitable. In January 2004,
following a cold spell with several nights of frost, 93 bats were found throughout the system. The total of 55 Natterer’s bats makes this hibernation site one
of the most important in the country for this declining species. The presence of 32 brown long-eared bats is unprecedented for an underground site.
In January 2004, following a spell of cold weather, two barbastelles were found hibernating in bat bricks that had been erected 15 months earlier. This was only the second Essex record of this species during the last 50 years; hopefully, summer survey work using bat detectors will confirm the presence of a nearby colony.
Specially-manufactured bat bricks have been attached to the ceilings of
the bunkers and canvas material has been draped over coat hangers to
create crevices favoured by brown long-eared bats.
Tree trunks with bat-sized slots have been leant against walls and these
have been used by up to ten Natterer’s bats, with a maximum of four in one crevice.
Bats are usually to be found in the crevices provided, but occasionally
an individual such as this Natterer’s bat is found hibernating in the open.
The bat bricks have proved extremely successful with up to four bats being
found in a single brick. In this case, a single Natterer’s bat was found.