Three mist nets were erected along the woodland tracks in the early evening ready for the Barbastelle emergence. Unfortunately most of the bats were able to see the nets through their echolocation flying within inches before taking evasive action. Luckily for use one must have been dozing, a female that may or may not of have one young bat this year. This specimen was weighed and checked for its health before the radio transmitting tag was put on her. The transmitter weighed 4 grams and had a life of around ten days before the battery failed, this was glued to the fur on her back and a final check was made to ensure her safety and then she was released. For the next week people were appearing in the woods at night with receivers to follow the radio tracked bat. These instruments were tuned to the transmitter frequency and just after sunset the female bat left her roost with the others, approximately 15 individuals.

They did the usual flying around the wood for about half an hour before setting off the dusk light along an over grown hedge to the semi-ancient Eversden wood which is a coppice woodland that has been left almost untouched since the Second World War. For about one to two hours she fed in this wood with a number of other Barbastelles, she then sometimes returned to the roosting wood before flying off to the Eversden and Harlton Districts, though some nights she flew straight from Eversden wood. By this time it was usually very dark and this bat would fly straight across the arable fields and it took quite a few nights before her rough hunting area was defined. After hunting insects over 10 km away she would come back to the roosting woods on the Wimpole estate for awhile and then with many of the other Barbastelles she would fly back to the Eversden woods for what probably was her last meal with the others. It was very surprising to see how late these bats returned to their roost site, almost in broad daylight but using large hedges as cover.

There were three different roost sites used, all were in oak where they used dead and split branches including one completely dead tree. It would appear that each individual has its own hunting ground in the middle of the night and a communal hunting ground early in the evening and in the morning. The information gathered is extremely useful in addition to other work undertaken elsewhere in England and Wales; it will help conserve this rare bat that is even rare in Europe.

Wimpole Estate has a number of very good habitats for British bats and the number of species present reflects this here. In total eight species are confirmed through visual identification and by some the very characteristic echolocation calls in the right habitat. Recently the National Trust Centres have provided money for a more sophisticated bat detector and some bat roost boxes. The new bat detector will not only provide a means of education and evening walks but it will also help monitor species at Wimpole far more easily and with a greater confidence. The bat boxes will be sited in good locations, which will enable further monitoring work.

Pipistrelle (45): These bats were recently separated due to the difference in echolocation sounds. They are by far the most common bats but have declined quite dramatically in recent decades due to the same effect on wild birds.

Piperstrelle (55): Soprano piperstelle have an echolocation higher than the 45 pipestrelle, that is they have a call at 55 kHz. It is not all to clear as to the habitat preferences but they do like water bodies and the edge of woodlands at Wimpole

Brown long-eared: These bats are reasonably common on Wimpole estate. They will roost in buildings with large clear attic spaces such as the Hall, the Old Rectory and some of the farm buildings. These bats will come out very late at night to feed on insects, particularly Yellow Underwing moths which they mostly catch by pouncing on them when on the tree foliage. Having caught the moths they then usually have a temporary roost site such as in the Stable block where they take time to eat their dinner

Barbastelle: Recently these bats have been identified in the woodlands at Wimpole. These are very rare bats even in Europe. To date less than ten sites are known were this bat lives in Britain and very little is known about them. However they like woodland with an understory and feed mainly on very small moths (micro moths), they will also travel large distances to find the right type of prey. On bat detector their echolocation is easy to identify at 32 Hz and a distinctive tack tick tack tick.

Noctule: These are woodland bats feeding above the woodland canopy on large insects, cockchafers are very good. Their roost sites are mostly in old trees, which have cavities to roost in. The echolocation is low at around 30 Hz; this is roughly the same as the Serotine and Leislers bats. The call is also loud and reflects the need for these bats to locate their prey from a large distance away, up 100-200 metres away which is totally opposite to Natters and Brown long eared bats which hunt at distances of 1-5 metres away from the prey.

Natterers: A single male Natterers bat was found in the old smithy (April 2001) and is now confirmed at Wimpole. Male bats tend to be solitary and only seek out the females later in the year (September) to mate. In spring bats become more active as the temperatures increase especially when night time temperatures exceed 6 degrees centigrade.  These bats will hunt usually in woodland but small ponds and rivers may attract them too.

Serotine: A rare species that hunts over open pasture catching large insects like the dung beetles. Dung beetles are plentiful at Wimpole because of the livestock, especially the cattle. It is also important not to use certain internal insecticides on livestock as this can have a detrimental effect on dung fauna which the bats feed on a lot of the time. Their main roost sites are nearly always in large old buildings; Wimpole Hall is an ideal roost site which they use.

Daubentons: These bats were once called the water bat because they are almost always found skimming the surface of most water bodies. The Capability brown lakes on some nights can have large numbers of them skimming the surface in broad arcs catching aquatic insects. Their feet have grappling like claws, which also enable them to catch the emerging insects on the water.