Back when I was a student in the early 1980s I lived in the Staff Accomopdation at Langdon Hospital just outside Dawlish in South Devon, and so between 1982-5 I spent every summer out and about in the area. One of my favourite locations was Dawlish Warren Nature Reserve. Its website describes it thus:
'Dawlish Warren National Nature Reserve, Devon is located on a long sand spit at the mouth of the River Exe. The sand spit is home to many species of wildlife and holds geomorphologic interest. Habitats at the Warren, include dunes, grassland, ponds, salt marsh and mudflats. The Warren is also the main roost for wildfowl and wading birds of the Exe Estuary.'
This is OK as far as it goes, but it doesn’t even approach an encapsulation of the genius loci of this magickal place. In the middle of a slightly down-at-heel tourist area it is an oasis of wild beauty. As a student I used to go there to watch the oyster-catchers who congregated (and prersumably still congregate) in enormous numbers on the edge of the estuary, and occasionally one would get a glimpse of a sand lizard, those beautiful and ridiculously rare little reptiles that were once almost extinct in this country.
But now there is another ridiculously rare creature, and what is more important is that it appears to be making some sort of a comeback.
The large tortoiseshell (Nymphalis polychloros) was once a common British species. In Victorian times, according to the excellent UK Butterflies website, 'the Large Tortoiseshell was considered widespread and common in woodland in southern England. However, this beautiful insect has since suffered a severe decline and there have been less than 150 records since 1951. This butterfly, whose numbers were always known to fluctuate, is generally considered to be extinct in the British Isles, with any sightings considered to be migrants from the continent or accidental or deliberate releases of captive-bred stock. Several causes of its decline have been suggested - including climate change, parasitism, and the effect of Dutch Elm disease on one of its primary foodplants. The hope, of course, is that this butterfly is able to once again colonise our islands'.
Adrian Hoskins writes that for some unknown reason (and he suggests that it is unlikely to have been parasitism) the species declined massively in the early part of the 20th Century, and although it was quite widespread again in the 1940s, never really recovered. Interestingly, his dates are different to those given elsewhere, saying that it became rare in the 1970s and was extinct by 1990. http://www.learnaboutbutterflies.com/Britain%20-%20Nymphalis%20polychloros.htm
He goes on to suggest that it was the arrival of Dutch Elm disease that finally delivered the coup de grace to this beautiful insect, something upon which most authorities seem to agree.
The other day, whilst I was doing something completely different, I came across a report that 'A Large Tortoiseshell, only the third site record, was in the Buffer Zone' on the 23rd March. It was seen again in early April.
Incredibly excited, I looked around for the other two records and found that they had occurred in 2007 and 2008, but as I cast my net wider, it turned out that despite having been probably extinct in the UK since 1953 and declared so in 1983, these elusive butterflies are quite often seen in Devon.
Look at these reports from http://www.britishbutterflies.co.uk/:
Reported sightings of the Large Tortoiseshell in Britain during 2007:
14-07-07 - Large Tortoiseshell seen Brownsea Island Dorset.
14-07-07 - Large Tortoiseshell seen at Gosport and Stokes Bay Golf Course (Grid Ref: SZ613981).
14-07-07 - Two probable Large Tortoiseshell seen at Gosport and Stokes Bay Golf Course (Grid Ref: SZ606978).
10-07-07 - Large Tortoiseshell seen at Shortwood Common Devon (Grid Ref: SY849052).
09-07-07 - Large Tortoiseshell seen in the grounds of Bicton College, Devon.
09-07-07 - Large Tortoiseshell seen Brownsea Island, Dorset.
08-07-07 - Large Tortoiseshell seen Tout Quarry, Portland, Dorset.
07-07-07 - Large Tortoiseshell seen in Clanfield, north of Waterlooville, Hampshire.
07-07-07 - Large Tortoiseshell seen in Church Knowle, Dorset.
07-07-07 - Large Tortoiseshell seen in Arne, Dorset.
06-07-07 - Large Tortoiseshell seen at Peak Hill, Sidmouth, Devon (Grid Ref: SY114869).
05-07-07 - Large Tortoiseshell seen in the New Forest, Hampshire.
29-06-07 - Large Tortoiseshell seen at Shortwood Common, Budleigh Salterton, Devon (Grid Ref: SY849052).
29-06-07 - Large Tortoiseshell at Herstmonceux Castle, Sussex.
26-06-07 - Large Tortoiseshell seen at Littlehampton Bridge, Sussex.
20-06-07 - Large Tortoiseshell seen at Musbury Castle, Devon (Grid Ref: SY289939).
21-06-07 - Large Tortoiseshell at Crouch Gardens, Seaford, Sussex.
04-05-07 - Large Tortoiseshell seen in a garden in Lydd-on-Sea, Kent.
06-04-07 - Large Tortoiseshell seen in Portland Bill flying in from sea.
03-04-07 - Large Tortoiseshell seen near Sugarloaf Hill, Kent.
03-03-07 - Large Tortoiseshell seen at Portland Bird Observatory, Dorset.
27-01-07 - Large Tortoiseshell seen at Portland Bird Observatory, Dorset.
Reported sightings of the Large Tortoiseshell in Britain during 2006:
05-05-06 - Large Tortoiseshell seen at Aylesbeare, Devon.
05-05-06 - Large Tortoiseshell seen at Branksome Dene Chine, Poole, Dorset.
05-05-06 - Large Tortoiseshell seen at Boscombe Cliffs, Bournemouth, Dorset.
08-04-06 - Large Tortoiseshell seen at Worth Matravers, Dorset.
The website goes on to say:
'Due to unofficial or accidental releases by butterfly breeders who import eggs and larvae from dealers from outside the UK, it is impossible to tell at present if there are self sustaining breeding colonies present in Britain or if the reported sightings are of released captive bred individuals. Sadly this practice makes the possible conservation of this species if if does persist in very low numbers very difficult and understanding the true nature of the distribution and habitat requirements of the Large Tortoiseshell in the UK almost impossible. Some sightings are also thought to be of naturally occuring migrants from mainland Europe.'
This is quite possibly true but if so, it would suggest that there are no amateur lepidopterists living outside the south coast of the UK, which is where all the reports are from, and it ignores the fact that in 2008, no less a personage than the head Wildlife Officer of the National Trust wrote in 2009:
'The Large Tortoiseshell butterfly, which was thought to be extinct in the UK, has bred successfully on National Trust land in south Devon, with other sightings recorded along the south coast of England'.
Writing on his invaluable ‘Learn about Butterflies’ website, Adrian Hoskins says:
'In June and July 2007 several fresh specimens were recorded at various locations on the Isle of Wight and scattered along several miles of the Hampshire coastline. Records of worn specimens from other coastal sites every spring from 2007 to 2010 appears to indicate that the butterfly might now be breeding regularly but in very low numbers in southern Hampshire or on the Isle of Wight. On the other and it is equally likely that one or more amateur enthusiasts are releasing captive-bred European livestock of this butterfly breeder's favourite in an attempt to re-establish the species in Britain.'
So is it extinct or not? The available evidence would tend to suggest probably not, and that as well as the hypothesised breeding populations in Hampshire and the Isle of Wight, it is slowly colonising the south coast of Devon and Dorset. This is particularly interesting because, as has already been mentioned, when it was a well known British resident, it was best known from the southeast and the midlands.
Once again this provides an object lesson as to the veracity of Heuvelmans’s maxim that there are indeed lost worlds everywhere. Whilst there are undoubtedly new species to discover in far flung corners of the globe, the recent rediscovery of the English pine marten, green lizards in Dorset, the pool frog as a British species and now the apparent renaissance of the large tortoiseshell, would suggest that our knowledge of our own native wildlife is far from complete.
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