Yorkshire Bats

The diversity of bats tends to decrease the further North you go in Britain, so not all British bat species are found here. The table on this page shows which of the species occur in Yorkshire, and more information is given below on some of the more common bats. We also have Distribution maps for some species.

Of course, it has recently been discovered that pipistrelles are two separate species. The main distinguishing feature is the peak frequency at which they call - either around 45kHz (now known as the Common Pipistrelle) or 55kHz (the Soprano Pipistrelle). There are some suspected minor differences in appearance, but by far the easiest way to identify them is by the use of a bat detector.

When the news broke about the discovery of the two species it was widely proclaimed that most Yorkshire bats were of the 45kHz type while 55kHz bats were commoner across the Pennines. Whilst there may be some truth in this, 55kHz bats have been found at many sites across the county - a recent survey of farm woodlands by MAFF Central Science Laboratory found 55kHz pipistrelles at a third of sites, whereas 45kHz bats were found in nearly all the woodlands. 55kHz bats seem particularly common in the Derwent valley.

As well as catching insects in free flight, brown long-eareds are gleaners, picking insects off the foliage. Thus, they often fly against a background of dark trees, rather than against the sky, making them almost invisible. Their echolocation calls are extremely quiet, being only detectable when the bat is a few feet away, even in an enclosed space. Even where roosts are known, it is perfectly possible for the bats to slip out in the evening unseen. Only the lucky observer, catching a rare glimpse of the species flying away from a cluttered background, will see its large ears outlined against the sky.

Because of the difficulty of observing the species in the wild, especially with a bat detector, there are far fewer records of brown long-eared bats in North Yorkshire than of pipistrelles. It is also impossible to separate the species from the grey long-eared bat, except in the hand, so although it is thought that the grey long-eared is very rare and confined to southern England, there must always be a doubt as to the identity of a long-eared bat in free flight. Most records, consequently, are of bats roosting in houses.

A number of roosts have been recorded over the years in locations as widespread as Sutton-on-Derwent, Scarborough and Helmsley Castle. There are several roosts on the Fountains Abbey estate including one in the roof space of Fountains Hall and surveys of Beningbrough Hall have also shown widespread evidence of use. Feeding bats were watched above the steps to the clock-tower at Beningbrough last summer. Around Newtondale brown long-eared bats have been recorded using Forestry Commission bat boxes in both summer and winter and the species is known to hibernate in the windy pits around Helmsley. Typically, hibernating long-eareds are found singly, tucked into crevices in tunnels and caves, as was one at Fountains Abbey last winter.

One or two roosts are known in the county. A couple of years ago a roost in an ash tree came to light when the tree was partially destroyed by a summer storm. The tree was beside the River Ouse in York, only a few hundred metres downstream from another known roost, this time in the rather unlikely setting of the modern, concrete Clifton Bridge. The two roosts were probably used by the same colony of bats.

Noctule bats preference for tree roosts dictates its need for mature and over mature trees. Consequently it is perhaps surprising that noctules appear to be fairly commonly encountered hunting over the largely treeless Vale of York. They are undoubtedly attracted by the quantities of insects to be found over the major rivers which flow through the Vale.

The largest known noctule roost in Britain is at North Ferriby in East Yorkshire where the highest count has been 234 bats, all living in a hole in an old pollarded beech tree in a suburban garden. Numbers 'at the roost fluctuate considerably and the colony certainly appears to use more than one site, a fact characteristic of noctule roosts elsewhere.

Many Daubenton's roosts are in bridges, canal tunnels and the like, from which they may fly up to 10km to feed. It can, therefore, be quite a challenge to find those roosts which are in tree holes nowhere near the water. Some roosts, mainly in bridges or old buildings, are known to the Group and these have been the subject of regular monitoring over the years.

In winter, Daubenton's is one of the species known to hibernate underground. They are often solitary, but it is possible to find small groups in one cave. Many years ago fourteen were found in a small cave in the county. However, they are usually tucked in difficult to spot places such as tight crevices, or even among the loose scree and rock on the cave floor.

The echolocation calls as heard on a bat detector are rather like those of a Daubenton's bat, making identification in flight very hard. There are subtle differences in the calls, but while Daubenton's can be identified by listening and observing its hunting method over water, the Natterer's feeding behaviour in its preferred woodland edge habitat is less obvious.

A few Natterer's roosts are known and some have been established for many years. A roost at Fountains Abbey, for instance, was confirmed to still be occupied by Natterer's bats in 1999 after at least 15 years. Another, just into East Yorkshire at Low Catton has been the subject of studies by the East Yorkshire Bat Group this year in an effort to minimise the level of droppings deposited in the church.

In hibernation Natterer's bats are mostly found singly, often near cave entrances, where they seem to prefer the cool conditions.

These species appear to be widely but thinly distributed across the county. Whilst they are certainly nowhere near as common as species such as the Brown long-eared bat, they are probably more widespread than is realised. In common with many Myotis bats they cannot be confidently identified in flight using a bat detector and there are still some disagreements among batworkers as to the identity of some specimens, even in the hand.

Although fairly widely distributed in England, its distribution appears to be rather patchy. In some places it is apparently quite common. One such area is around Wakefield, where it has been found roosting in a number of houses as well as in bat boxes. Although some of these roosts are less than five miles from the North Yorkshire border, it has yet to be definitely confirmed from the county.

There is just one confirmed record of the species in the county, made in 1990 only just in the county at Burton in Lonsdale. As far as is known, this record has never been followed up. More recently, there have been suspicions that some bats that feed around street lights in Helmsley could be Leisler's, although this too has to be confirmed. It is also thought that Leisler's may have been flying over Burton Salmon in the south of the county on one night in 1997, but again, there is no confirmation. Niall Moore from the Central Science Laboratory also reports three passes of Leisler's bat over their study area on one night in 1998, as heard on a time-expansion detector.

Given the presence of Leisler's bat in neighbouring counties and these occasional unconfirmed records in North Yorkshire, it seems likely that this species is present, although probably in very low numbers. Hopefully, the increased interest in bats and growing expertise in the use of bat detectors and the interpretation of the sounds heard on them will soon enable us to confirm this species on the North Yorkshire list.

On 4 June 1921 H B Booth, F H Edmondson and A Gordon found two adjacent clusters of Barbastelles in the basement of Helmsley Castle. At least fourteen specimens were taken and about 140 bats were present. Another specimen was found there in 1923 and a colony was smoked out of a tree in nearby Duncombe Park.

More Barbastelles were reported at the Castle from 1945 - 1950 and in 1951 fourteen bats were netted at a house in the town. The last records were of two specimens from Duncombe Park in April 1955.

Elsewhere, there is a report of a Barbastelle from the Great Avenue at Castle Howard in 1934 and one from York in 1968, although there are no further details regarding this last record.

Although everywhere rare, recent bat detector work in other parts of England has revealed hitherto overlooked Barbastelles. It would be very worthwhile for the North Yorkshire Bat Group to organise a search for this species in the Helmsley area over the coming summer in an attempt to establish if it is still present.

During the 19th century Lesser horseshoes were reported from a number of locations in the county, but especially in Nidderdale and Ryedale. In the 20th century records tended to become concentrated mainly in the Helmsley area where specimens were still being collected in the 1940s. In February 1983 a group of researchers led by Bob Stebbings suggested that the species may still be present in the Helmsley area by locating suspected droppings at Bucklands, Antofts and Ashberry Windy Pits. There is also an unconfirmed record for October 1986 from a property near Sutton Bank.

The area around Helmsley and the fringes of the North York Moors, with its agriculture still dominated by livestock farming, would seem the most likely part of the county for this species to survive. Over the coming year or two, the North Yorkshire Bat Group intends to re-check the sites where this species was once found in an attempt to discover if a small population still exists in the area.

Home page