Saturday, 20 September 2008

Very rare visitor reaches Kelling

The arrival of a Particoloured Bat at Kelling last Saturday caused something of a stir among local naturalists. This is just the third record of this northern European species in Norfolk and the first since one was found in a wood yard at Great Yarmouth in August 1968. On that occasion the bat was thought to have arrived with a load of timber imported from the Baltic but the most recent arrival appears to have been unaided, with the bat reported flying in off the sea. Fortunately, the bat made use of an old pillbox on the beach and so Steve Gantlet of Birding World magazine was able to snap a brief photograph as it roosted.

There have been at least 23 confirmed records of this migratory species since 1980 and it is now recorded almost annually from somewhere in Britain, with Shetland and various North Sea oil and gas installations hosting the bulk of the records. However, it has been recorded as far west as Plymouth, Wiltshire and the Isle of Wight. Although recorded in all months of the year except February, most of the records come in spring or autumn, hinting at the migratory nature of the movements that may bring this bat to our shores. The normal breeding range is from the Alps and the Balkans in the south, Norway and Germany in the west and then up through Russia and east to the Pacific coast. Records from Britain, France and the Netherlands are therefore of migrants that have strayed west of their normal migration routes.

It may seem odd to think of a bat migrating, especially when you consider that most of our bat species survive the winter by entering hibernation. However, the more northerly populations of Particoloured Bat face harsh winter conditions and so are forced to move south or southwest of their breeding range to find somewhere more suitable for wintering. Movements of several hundred kilometres are typical, but there is a record of one moving some 1,780km, a staggering movement for such a small and seemingly delicate creature.

With a covering of long dark fur, tipped with silver-grey, this handsome bat has the appearance of being frosted. The fur of the underside is a bright creamy white, which contrasts with the darker upper surface. In flight the wings appear narrow and pointed, and these features equip this bat with a fast and manoeuvrable flight, ideal for catching small flies in open spaces. It is these flies that make up the bulk of its diet.

Although very much still a vagrant to our shores, it is interesting to note the scatter of summertime records which may just suggest that this bat could colonise Britain.

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