Dingy Skipper Survey 2005

by Rob Parker

SUMMARY

The 2005 survey continued the intensive study of 2004, refining our knowledge of the extent of the Dingy Skipper's distribution.

The newly found colony in the Archery area of King's Forest was found to be flourishing, with a peak count of 115, and an expanded-flight area. On the other hand, the established colony at RAF Barnham had a very poor showing, with just one Dingy Skipper seen in rwo separate visits. This abrupt change is probably related to the recently introduced sheep grazing regime, and needs . careful management, if the colony is to survive. Continued checks of former sites did not reveal any unexpected records, and there were only· a few sightings in the Chalk Lane areas. A number of possible sites in peripheral areas were investigated this year, notably along the Cutoff Channel, where no Dingy Skippers were found, although the banks of the same waterway do hold good populations just a few miles into· Norfolk. Tlie population on the Devil's Dyke remains strong, although this lies just outside VC26, i.e. in Cambridgeshire's recording area. The very promising site at the Thetford Rifle Range was inspected, but no Dingy Skippers were found despite the apparently suitable habitat. The season was again later in the Brecks than in Cambs, and this was exaggerated by the cold wet spell in early May. The flight period became rather extended, and some Dingy Skippers were still flying in King's Forest on June 18th.

All visits were conducted with the landowner's consent, or along public rights of way. A total of 17 sites were visited during the 2005 flight period. Dingy Skippers were found only at the established sites, including an isolated, but stable colony at Center Pares. The butterfly appears to be holding its own in a very limited area of the Suffolk Brecks, covered by just 5 tetrads.

2005 SURVEY The Dingy Skipper was on the wing from late April elsewhere in UK, and on the Devil's Dyke (Cambs/Suffolk border) by May 2nd, but the Brecks population was again later.

None were flying on May 6th, and the first definite record was from Wardwell on May 14th. The cool wet spell at the start of May had the effect of extending the flight period. This finished at Devil's Dyke by June 8th {last sighting May 28th), yet they were still present in King's Forest on June 18th. The survey involved 19 participants, and the main events were:

Apr 29th - Training at Barnham (Spring Survey Event).

May 12th - Survey along Cut-off Channel in Lakenheath area.

May 14th - Counts at Wardwell & Archery area, but nothing found at Chalk Lane or to the north east.

May 18th - Count at Center Pares, repeated by staff on Ma!J 27th.

May 23rd - RAF Barnham survey - negative, repeated Jun 3rd - only one seen.

May 24-25th - Surveys at Thetford rifle range

May 25th - Chalk Lane; 2 seen.

May 30th - King's Forest; one seen west of road (first since Millennium survey).

May 6-30th - Negative searches made at Euston, Sketchfar, Marmansgrave, Barnhamcross, Berners Heath, also Shepherd's Grove and Haverhill etc. A grant from Awards for All enabled volunteers to be reimbursed for mileage undertaken during the survey. The sites visited are listed individually below, as active, defunct or for future investigation.

ACTIVE COWNIES

RAF Barnham [TL 8580/8680}. The first visit to the Barnham Training Area, in fair weather found not a single Dingy Skipper, even though they were flying elsewhere on that day. This is alarming, at what ought to be our strongest colony. Sheep now graze the trainjng area, and 64 were in the Dingy Skipper area on that day. By arrangement, English Nature attended the next visit on Jun 3rd to assess the impact of grazing on the sward. On that day, just one Dingy Skipper flew, and the flowering of the Bird's-foot Trefoil was late.

King's Forest {Wordwell) [TL 834732}. This site recorded a maJOmum count of 16 on May 27th, and again the Dingy Skippers were flying further to the south and west than the main ride, extenrung their domain to include the sheltered glades to the west of the tree line.

King's Forest (Archery) [TL831737]. Only 300m north of the Wordwell site, but cut off by a forest compartment, lies an east-west track with good Bird's-foot Trefoil along the margins. This links to an area used for archery practice, part of which is kept mown. This year's count coincided with good weather and fresh emergences, and a team of 6 counted no less than 107 Dingy Skippers active on May 14th. On subsequent visits, the flight area was found to extend even further east and west than the first survey, its northern limit being the mature coniferous edge at TL830739. The Bird's-foot Trefoil grows over a wide area, and appears to flourish under the mowing regime implemented for the archers.

King's Forest (Chalk Lane) [TL827752]. Numerous visits to this tradjtional site proved negative, although at least 2 were seen dose to the heathland regeneration area on May 25th. The tree felling discussed last year with the Forestry Commission has not yet come to pass. The 2004 records of strays further east and north were not reproduced, despite several independent searches.

Elveden (Center Pares) [TL810805). A site visit with Center Pares Ecology Manager found at lease 9 Dingy Skipper flying on May 18th, and staff revisiting on May 27th were able to find 15. The area mown as the bird walk will be managed with the Bird's-foot Trefoil in mind.

DEFUNCT SITES

King's Forest Oohn O'Groats Cottages) [TL818737}. One Dingy Skipper was found on the track from the main road towards John O'Groats Cottages, and this was the first sighting on the west of the BI 106 since the Millennium survey. However, there is not much suitable habitat in this area, and the significance of one stray crossing the road should not be overstated (this point is only 200m from the edge of the Archery colony}.

Kings Forest South [TL7872/8073/8272SW}. Not specifically targeted this year, but no casual records received.

Barnhamcross Common [TL86481 l]. This site lies adjacent to RAF Barnham, and occasional strays are seen on the south edge of Barnhamcross Common, which lies in administrative Norfolk, but in Suffolk's biological recording area. Several visits were made to the southern margin and the wider area of the common, but no Dingy Skippers were found.

Marmansgrave Wood [TL8480}. An abundance of Common Blues in this area suggest that Bird's-foot Trefoil may exist along the footpath, but the bracken encroachment continues, and the former site may be considered defunct. A sheep-grazed area in the Elveden Estate's Sketchfar domain has one promising looking corner at TL836801, which deserves a visit next year.

Dingy Skipper

by Douglas Hammersley

Euston Quarry [TL896775}. This wonderful CWS has everything that ought to make a good Dingy Skipper site, including Bird'sfoot Trefoil and a Common Blue colony. It was inspected early this year, on May 8th, but for the third year in succession, no Dingy Skippers were found.

OTHER SITES

(Inspected, with negative results)

Cut-off Channel [TL7386]. , During Norfolk's 2004 survey for Grizzled ancf Dingy Skipper, both were found along the watercourse known as the Cut-off Channel, which has a chalky double embankment along a nine mile stretch in Norfolk. Visits to the Suffolk stretch were made on May 12th (after finding DS flying \n nearby Norfolk), but there was a shortage of Bird's-foot Trefoil, and nothing was seen. Thetford Rifle Range [TL8480J. This MoD site lies in administrative Norfolk, bur is in Suffolk's biological recording area. It has plenty of Bird's-foot Trefoil in a suitably sheltered area, and was walked extensively on May 24th in poor weather and again on May 25th in hot weather. Although the habirat looked excellent, it was disappointing not to find any Dingy Skippers. Bemer's Heath [TL7977J. The northern edge of Berner's Heath has plenty of Bird's-foot Trefoil along the rather exposed northern edge. It was visited twice (May 16th in poor weather & Jun 17th in good conditions) without success.

Sketchfar [TL836801J. See remarks above, under Marmansgrave Wood.

Shepherd's Grove [TL987l}. This area has some Bird's-foot Trefoil on the former airfield, not far from the planned IKEA development. It was surveyed on Jun 8th, but did not appear suitable for Dingy Skipper.

Haverhill Industrial [TL6844). This area (mainly just outside VC26) has Bird'sfoot Trefoil, and had been suggested as a postindustrial site worth inspection. Three visits were made, but no Dingy Skipper were found.

Rob Parker, County Butterfly Recorder. July, 2005

LANDOWNERS (and other interested parties, for reference)

Euston Estate (Chris Spicer) Elveden Estate Qim Rudderham) Thetford IP24 3TQ Stamper Farms O. Stamper, West Farm) IP24 North Farm (Rob Watson) IP24 East Farm (David Heading) Barnham IP24 2QN Forest Enterprise (Nick Gibbons) RAF Hanington (Gwyn Smith) Center Pares (Ecology Manager) Brecks Countryside Project Norfolk Butterfly Recorder (Patrick Bonham) BC EoE Regional Officer, Butterfly Conservation (Sharon Heade) East of England Tank Museum (Sean Hindle) Barnham IP24 Environment Agency Suffolk Biodiversity Partnership