Thursday, 28 February 2013

Sunday, 17 February 2013

First one to blink ...

Roe Deer

The roe deer, Capreolus capreolus, is primarily an animal of open mixed, coniferous or purely deciduous woodland but is also capable of adjusting to a wide range of other environments. It has also penetrated many towns, making use of gardens, parks and other open spaces where suitable food and cover exist. It may often be seen well out into open farmland, particularly when occurring at high densities.

Roe deer are indigenous to Britain, having been present since at least the Mesolithic period (6,000 to 10,000 bp). The clearance of forests and over-exploitation by hunting led to roe deer becoming extremely scarce in the medieval period. By 1700 it was considered extinct in southern and central England and all of Wales, surviving only in remnant woodlands in parts of the central and northwest Highlands of Scotland. A number of reintroductions during the Victorian era, and their subsequent natural spread aided by an increase in woodland and forest planting in the 20th century, has meant that roe deer have become widespread and abundant today.

A roe doe listens and watches ...

Friday, 15 February 2013

After dark ...

Bats in the attic?


Despite the loss of over 90% of our bats in the past 50 years or so, 18 species of these increasingly uncommon nocturnal creatures can sometimes still be found in southern Britain. Although legally protected, most species of these tiny intelligent mammals sadly continue to decline in numbers, mainly due to loss of habitat and changes in farming practice. All British bats eat only insects, populations of which have also reduced massively in the past fifty years or so. In Britain, a female bat has only a single baby (pup) each year, and often cannot give birth in poor summers; such as those we have experienced recently. Such slow reproduction makes it extremely difficult to reverse the decline of these beautiful and delicate mammals.

Most of our bats like to roost in trees, but a few species have adapted to take advantage of the opportunities offered by buildings at certain times of year. For example, a warmer environment can help a bat rear its pup during the summer. The pup is reared on its mother’s milk until it can fly, which may be as soon as three weeks after it is born. By autumn, the house dwelling maternity colony will typically be dispersing to mate and then to hibernate, perhaps in trees or underground sites.

Although they occasionally do, their presence needn’t worry householders – in fact most people remain quite unaware of their secretive little lodgers. Bats by their very nature are clean, gentle little animals, which spend much of their time grooming. They don’t build nests, so won’t bring any messy materials into the house and, perhaps most important of all, they don’t gnaw and chew at things, so won’t cause damage to electrical wiring and cables.

Bat droppings are sometimes found beneath roosts, but these are quite harmless and are not known to harbour disease. Droppings are sometimes seen on outside walls and windowsills near to roost entrances, but can also accumulate in lofts. If swept up after the bats have left, they make excellent fertiliser for houseplants. Bat and mouse droppings look very similar, but there is an easy way to tell them apart. Bat droppings consist only of the dried out fragments of insects and, if rolled between your finger and thumb, they will crumble away into dust; they also have a slight ‘sparkle’ about them. On the other hand, mouse droppings are solid, generally dull in appearance and remain in one piece.

Which bats live in houses?

The two very rare horseshoe bat species, the greater horseshoe (Rhinolophus ferrumequinum), and the lesser horseshoe (Rhinolophus hipposideros)like to roost in buildings, but are no longer regularly found in the south east of England. None have been recorded in Kent and Surrey for many years, and a mere handful remain in West Sussex. Usually found are our most common bats, the common pipistrelle (Pipistrellus pipistrellus) and the soprano pipistrelle (P. pygmaeus), which as crevice dwelling species, like to tuck themselves into gaps around the outside of properties rather than enter the loft space. They tend to do this mostly in the summer months when groups of females will cluster together in a warm spot to rear their young hidden beneath barge boards, hanging tiles and so on. In winter, odd individuals are sometimes found hibernating in similar gaps, but this time in the coldest rather than warmest places on the house. Perhaps surprisingly, pipistrelles seem very fond of modern houses, especially where small gaps and splits have opened for them into which they can squeeze. Though little more than an inch (2.5cms) in length, a pipistrelle can eat up to 3000 midges in a single night, and needs to do so to fuel its energetic lifestyle.




Another house specialist is the brown long-eared bat (Plecotus auritus), small groups of which will congregate in the lofts of (usually) older houses for a few months in the summer, again whilst the young are being reared. Larger than the tiny pipistrelle, it has huge ears, almost as long as its body, which it uses to listen by means of echolocation for its insect prey. The ears are tucked safely beneath the wings for protection whilst the animal is at rest. An individual bat will occasionally remain in a cold part of the loft to hibernate. A much rarer house dweller, and one of our largest bats, is the serotine (Eptesicus serotinus). Several times the size of a pipistrelle, it is still very small - a little over three inches (8cms) in length, although its wings may span over a foot (>30cms) in flight. These favour the lofts and attics of houses built at least 100 years ago where a few will occasionally roost during the maternity period. They have also been known to hibernate, usually singly, in roofs or cavity walls. Serotine bats are particularly fond of flying beetles such as cockchafers, which they catch on the wing. Other species of bat are much rarer in England and are very seldom found in houses.

Advice on your bats

If you have any concerns about bats in your property, do call the Bat Helpline on 0845 1300 228 – they can provide lots of advice and literature on bats, and even arrange free advice where building repairs, timber treatment and so on are necessary in or near a roost. Their web site www.bats.org.uk provides a wealth of information about bats, and many leaflets can be freely downloaded. They also run a rescue service – so if you find a grounded bat, give them a call and someone will be able to help.

Bats and rabies

The European strain of rabies found in bats is extremely rare in Britain. Only ten cases have been identified since 1986, all of them in a single species that does not roost in houses. There is no need to worry about rabies if you do not handle bats – the disease is only passed via a bite or scratch, or from an animal’s saliva coming into contact with eyes, mouth, nose or an open wound. As a precaution, bats should not be handled. If it is necessary to do so in the case of a grounded or injured bat, gloves should be worn - and don’t forget to call the Bat Helpline, as detailed above, for advice or support from a local bat worker.

My thanks to Martyn Phillis (Surrey Bat Group) for his assistance with this article. All images copyright Martyn Phillis.

Thursday, 7 February 2013

Arvicola amphibius ...

European Water Vole

"Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats”

Rat, Chapter 1 ...

Kenneth GrahameThe Wind in the Willows


The European water vole, Arvicola amphibius, Linnaeus (1758), formerly A. terrestris, is widespread across Europe where it lives in the well-vegetated banks of slow moving streams, rivers, dykes and other waterways. It is found throughout Britain where it is generally confined to low ground. It is absent from Ireland. The extensive waterside burrows of these strong swimmers have many levels that help to prevent flooding, as well as chambers for nesting and food storage. Burrow systems are typically located in the steepest parts of the bank and usually have underwater entrances to give the animals a secure escape route if danger threatens.


A. amphibius has a diet of grasses and waterside vegetation, though other broadleaved plants are also eaten. Where blades are bitten off the imprint of the two large incisors is both prominent and diagnostic. It is not uncommon to see "lawns" of closely manicured grass, occasionally with piles of chopped food, around burrow entrances. A. amphibius tend to be more active during the day than at night. The males range along about 130 metres of water bank, while females restrict their range to about 70 metres. Ranges of both sexes and all age classes are reduced during the winter period. They deposit their distinctive black, shiny faeces in latrines, which occur throughout and at the edges of their range and wherever they leave or enter the waterThree or four litters a year are typical. In mild springs the first of these can be born as early as March or April; though adverse conditions will delay breeding until May or even June. There are about five young in an average litter, which are born below ground in a nest lined with finely shredded grasses and reeds. Although blind and hairless at birth, the young develop quickly and are weaned at 14 days. On average, water voles only live about five months in the wild.

Their most important predators are mink and stoats; though other predators are known to take them. They have sadly experienced one of the most severe declines of any wild mammal in Britain during the 20th century. Changes in farming practices during the 1940s and 1950s caused the loss and degradation of suitable habitats but the most rapid period of decline was undoubtedly during the 1980s and 1990s when the American mink (Neovison vison) spread rapidly across the country having been released from fur farms. Between 1990 and 1998, the population dropped by a staggering 90%.

Arvicola amphibius is an excellent flagship species and one which we should endevour to protect. Their presence reflects a healthy aquatic environment and associated waterside communities.

Sunday, 3 February 2013

Extinction and hope ...

Lycaena dispar …

“The beauty and genius of a work of art may be reconceived, though its first material expression be destroyed; a vanished harmony may yet again inspire the composer; but when the last individual of a race of living beings breathes no more, another heaven and another Earth must pass before such a one can be again.”

William Beebe (1877-1962)
American naturalist, entomologist, ornithologist, marine biologist, explorer and author.


The above quotation has always inspired me. Recent visits to the Hope Department of Entomology at the Oxford University Museum of Natural History (OUMNH) have left me pondering with sadness, the ultimate extinction of some species of butterfly from the British Isles and the worrying decline of many others.

It is all too easy to blame the collector for the demise of a particular species or race; although the greediness and irresponsible actions of some early collectors undoubtedly played a very important part in the loss of the beautiful Large Copper (Lycaena dispar ssp. dispar), that was endemic to the British Isles (Feltwell, 1995; Ford, 1967). In the case of L. dispar dispar, the changing fenland management and, in particular, the drainage of the fens, also played a significant role in its demise due to critical habitat loss. This, coupled with the lack of any protected status for the butterfly and its required habitat at that time, pushed the British subspecies, dispar, into extinction in the Fenlands around 1851 (Dennis, 1977).

It should be noted that although 1851 is often quoted in text as the date of extinction of L. dispar dispar, records exist as late as 1864 (Irwin, 1984, cited in Feltwell, 1995; Asher et al., 2001). These include records as far north as Walkeringham, Nottinghamshire by Miller, and Gainsborough, Lincolnshire by Farrington and Miller (Dennis, 1977). It is also reputed to have ‘definitely inhabited the Somerset marshes’, with a record by Crouch in 1857 (Allan, 1966, cited in Dennis, 1977). Records from other locations also exist.



In 1909, an unsuccessful attempt was made to introduce the continental subspecies, rutilus, into Wicken Fen, Cambridgeshire; the main reason for failure being the scarcity of its food plant (Ford, 1967). Several years later, in 1913-14, Captain E. B. Purefoy successfully introduced rutilus into a snipe-bog at Greenfields, Tipperary in Southern Ireland. This colony existed until at least 1928 (Dennis, 1977; Ford, 1967). With the exception of supplementation of adults in 1926 and 1943 from Dutch stock, the colony was self-sustaining. It was last observed in 1954 (Lavery in litt., cited in Emmet and Heath, 1989). 1926 also saw an attempt to introduce rutilus to a marsh in Norfolk, the stock coming from Ireland. This colony only survived for several years as conditions, once again, proved unfavourable (Ford, 1967).

In 1915, a new race of the Large Copper, batavus, was discovered in Friesland, Holland. Sadly, due to drainage schemes and irresponsible collecting after its presence was made known, it was on the verge of extinction within a few years (Ford, 1967).

Batavus, morphologically, is far more comparable to dispar than rutilus (Ford, 1967; Frowhawk, 1934; Thomas and Lewington, 2010). It was therefore decided that every effort would be made to stock Woodwalton Fen with this form; the first butterflies being released in 1927. Due to the early signs of success, a further release was made at nearby Wicken Fen in 1929-1930 (Dennis, 1977; Ford, 1967); though this colony only survived for around 12 years after an adjacent fen was reclaimed for agriculture (Duffey, 1974, cited in Feltwell, 1995). The colony at Woodwalton continued to prosper for many years, though was regularly supplemented with captive-bred stock. Despite fresh stock being introduced, along with regular caging of the larvae in order to provide a level of predatory protection, the colony was finally lost in 1969. Several further reintroductions were made until the programme was stopped during the 1990s (Thomas and Lewington, 2010).


Unfortunately, in Britain, all reintroduction attempts to date have ultimately ended in failure; though much has been learnt. In the Netherlands, batavus has shown a welcome recovery following a successful fen management programme (Thomas and Lewington, 2010). In Britain, the Great Fen project may shed a ray of hope on the future of the Large Copper in its former habitat. This ambitious 50-year project aims to create a huge wetland area comprising some 3,700 hectares (9,143 acres), between Peterborough and Huntingdon. It is destined to be one of the largest wetland restoration projects of its type in Europe. It encompasses both Holme Fen and Woodwalton Fen, two of the Large Copper’s most famous historic breeding grounds. So maybe all is not lost and, one day, in the hopefully not too distant future, we may see a successful reintroduction programme for the Large Copper in Britain.

Fingers crossed …

So what does this tell us …

It tells me that we must highly value and protect what we have. It tells me we must continue to research and keep learning – we may only have 59 native species of butterfly in the UK but there is still much we do not know. We must learn from our successes and we must learn from our mistakes. We must educate and we must conserve.

We have a responsibility …


******************

References

Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. and Jeffcoate, S., 2001. The Millenium Atlas of Butterflies in Britain and Ireland. Oxford: Oxford University Press, pp. 140-143.
Dennis, R. L. H., 1977. The British Butterflies – Their Origin and Establishment. Faringdon, Oxon: E. W. Classey Ltd, pp. 97-100, 104.
Emmet, A. M. and Heath, J., 1989. The Moths and Butterflies of Great Britain and Ireland. Colchester Essex: Harley Books, 137-139.
Feltwell, J., 1995. The Conservation of Butterflies in Britain (past and present). Battle, East Sussex: Wildlife Matters, pp. 55-69.
Ford, E. B., 1967 (reprinted). Butterflies. London: Collins (New Naturalist), pp. 142, 166-169.
Frowhawk, F. W., 1934. The Complete Book of British Butterflies. London: Ward, Locke & Co., pp. 260-268.
Thomas, J. and Lewington, R., 2010. The Butterflies of Britain & Ireland. Gillingham, Dorset: British Wildlife Publishing, pp. 101-104.

Great Fen Project. http://www.greatfen.org.uk (Accessed 2 February 2013).

Images copyright OUMNH. Photographed by Katherine Child, Hope Department of Entomology.