[Photo] Sonar detectors will be used at sunrise and sunset

Sonar detectors are to be used at the Houses of Parliament to find out what type of bats are roosting in its rafters, towers and gargoyles.
The Bat Conservation Trust said the historic Palace of Westminster could provide an ideal home for bats.

It is conducting a national survey of bat species with volunteers recording sightings at sunrise or sunset.

"Here in the heart of the city it is easy to forget that wildlife is all around us," said Madeline Moon MP.

The Bridgend Labour MP said she hoped the survey would "offer MPs the chance to experience a creature that is central to our legislative efforts to protect and increase biodiversity".

Bats use a sonar sense called echolocation to find their way around at night.

Survey volunteers will use sonar detectors to enable them to tune into the sounds the bats make and determine their species.

Bats roosting

Karen Haysom, of the Trust, said both the Thames and parks near the Palace of Westminster provided good foraging ground for insects.

"Bats like buildings that have lots of little gaps and old buildings can provide that for them.

"It's quite possible that there might be species such as pipistrelles roosting under the old tiles."

The UK is home to 17 bat species, all of which are protected by law because their numbers have been falling.

The decline has been blamed on their roosts being disturbed or destroyed and a decline in the abundance of insects.