COMMON PIPISTRELLE Pipiestrellus pipistrellus

 

Status: Native; Common

 

Habitats:  Woodland; Grassland; River/Pond; Parkland; Gardens

 

Britain’s commonest and smallest bat, with a body length of 5 cm, and a wingspan of around 25 cm (10 inches).  The fur is light brown, and face generally dark, giving rise to its alternative name, ‘Bandit pipistrelle’.

 

The Common pipistrelle feeds in a variety of habitats, including gardens and urban areas; evening surveys with an ultra-sonic bat detector will normally reveal its presence, echo-locating at a peak frequency of 45 KHz.  This species tends to feed along hedgerows, tree lines and on the dark side of buildings, typically at a height of 2 – 5 metres, and in a rather ‘fluttery’, untidy fashion.  Small moths, gnats, lacewings, caddisflies and mayflies form the main prey items; it has been estimated that a single bat may eat over 3500 insects in a night.

 

Of all bats, pipistrelles are the least sensitive to cold weather, remaining active in the autumn longer than any other species.  Some do not enter hibernation until December, but most hibernate from November until March or early April.  On average, pipistrelles live for 4 years, although individuals have lived for 16 years.

 

Although widespread, the Bat Conservation Trust estimates that the British population has decreased by 70 % since the late 1970s.

 

This species readily makes use of bat boxes (link to page showing how to build a bat box), and may roost in cracks and holes in trees.  However, this species most commonly roosts in buildings, favoured locations being cavity walls; soffit boxes; gaps behind barge boards, hanging tiles, raised lead flashing and timber cladding, behind loose-fitting window frames and lintels; and most commonly within the void between roof tiles and under-felt.  Pipistrelles may enter a gap as small as 1 cm, and can be very difficult to detect, particularly in the winter.

 

Pipistrelles rarely enter the living space of houses, although baby bats (born in June or July) sometimes get confused when searching for their mothers, and may be found in unusual places.  This species does not pose a health risk to humans, and does not cause structural damage, for example to timbers or cables.

 

If you are concerned that you may have bats roosting within your property, works to these areas should only proceed with caution after an initial search has revealed that bats (and bat droppings) are absent.  If in doubt, contact the local bat group first.