FIELD MEETING REPORTS
2007

Containing: 
 
Milden Hall Watch Group by Juliet Hawkins
God’s Square by Roger Dixon
Beetle along to Bentley by Colin Hawes
Dragonfly and Butterfly Walk by Robin Harvey
Dunwich Forest by Nigel Cuming

JOINT SNS / MILDEN HALL FARM
WATCH GROUP MEETINGS

13th April – The Great Snail Hunt

Ten children and four parents gathered for a snail hunt at Milden Hall near Lavenham. We found copious numbers of garden snails, door snails on tree bark (and underneath loose tree bark) and are quite well camouflaged until you get your eye in, garlic snails under logs in woodland (with glossy shells and their garlic smell is a bit of a giveaway). And lots of yellow white-lipped snails on nettles and other vegetation.

After looking very closely at the snails, discussing their quite strange courtship behaviour (did you know they fire chalky ‘love darts’ into each other?), observing them closely and trying to identify them (more difficult than you think with no snail expert around!), we finished with a thrillingly close snail race (no snail was harmed in the rush to the finish).

29th April – Dawn chorus in Groton Wood SWT nature reserve

Seven children and five parents managed to get up early for a 5.30am wander in the bluebell-covered Groton Wood. Without last year’s bird expert to guide us, identifying the birdsong was challenging and very much a group effort. No nightingale or cuckoo this year but we did distinguish green woodpecker, whitethroat, blackbird, wren, chiffchaff, blue tit, great tit and plenty of wood pigeon. And the bacon-buttie at the end was a treat.

Juliet Hawkins

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GOD’S SQUARE - a geological walk

Unusually for June this year, Saturday 14th June dawned bright and clear as 11 participants gathered for an afternoon GeoSuffolk / SNS geo-tour around the Abbey and Cathedral precincts in Bury St Edmunds. To add to the occasion, we were greeted by the rousing sounds and march-past of Kingston & Malden Scouts & Guides band, part of the celebration of a centenary of scouting. Leader Bob Markham produced copies of a super plan of the area with the geofeatures detailed and labelled to assist us during the walk.

We started by looking at an excellent example of Ginkgo biloba, with its unusual veining, a ‘living fossil’ that has been around from at least the early Jurassic (200 million years) and must have been a dominant feature of Mesozoic landscapes. From there we walked to the Dunkirk Veterans Association Memorial, which although inscribed as “mined at Caen” is clearly not pale creamy Jurassic Caen Limestone but Carboniferous Limestone with abundant Lithostrotion corals and other fossils.

The Abbey ruins themselves are of much interest, flint rubble walls with extensive use of Barnack Stone, a coarse cross-bedded Middle Jurassic fossiliferous oolitic limestone from Lincolnshire. The John Appleby rose garden contains a fine oolitic limestone sundial and USAF war memorial of distinctive coarse dark Swedish granite. The Yorkshire flags with their small-scale ripple structures were also noted.

The tour continued with a walk through the Great Churchyard, which dates from the C12th, to look at some of the monuments and memorials (a fascinating guide is produced by the Borough Council Leisure Services). Externally, the south wall of the Cathedral nave contains some (real) pale, fine grained Caen Limestone, and beautiful decorative flushwork can be seen at higher levels. Of particular interest is the new tower, which uses Clipsham and Barnack Stone (believed exhausted over 400 years ago) externally, and Ketton Stone internally, all from the Jurassic of Lincolnshire and quarried from just south of Peterborough. Over 7,500 tonnes of stone were used, with 600,000 ‘Suffolk Cream’ bricks made from the Upper Carboniferous Etruria Marl of Staffordshire. A further limestone, Doulton Stone, can also be found above the North Transept.

A final stop was to St. Mary’s Church. Here we looked at the alabaster-like marble memorial to the Suffolk Regiment on its Devonian limestone plinth, in which corals and algal masses could clearly be seen. Great slabs of dark grey Carboniferous Limestone, with corals and other fossils, and an unidentified brown Jurassic limestone with echinoid spines commonly make up the flooring. Also seen was a memorial brass set into gastropod-rich Purbeck Marble in memory of Frank Pretty of Sutton Hoo fame.

This was a fascinating tour of some of the geology of Bury St Edmunds, following on from the urban walk earlier in the year (see White Admiral 66), and there was something for everybody. Bob is to be congratulated for entertaining and educating us so well.

Roger Dixon

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16 June 2007 - BEETLE ALONG TO BENTLEY

With heavy rain at 10:30 a.m., rain again at 12:00 and a thunderstorm at 14:45, it did not bode well for the planned field meeting. However, the storm cleared, and thereafter the rain held off, giving eight stag beetle enthusiasts the opportunity to observe stag beetle activity in the field.

The meeting began in the new village hall, Bentley, with a power-point presentation illustrating the life-cycle and ecology of the stag beetle. There was then an opportunity for everyone to look at displays showing the results of the latest research into the ecology and behaviour of this endangered species and to examine some of the apparatus being used. The radio-tracking equipment being used this year to investigate stag beetle dispersal was successfully put to the test, searching for activated transmitters hidden in the hall. Live stag beetles and larvae, collected earlier in the week, were photographed, and participants were treated to a display of stag beetle flight, when a male took off, circled, and then proceeded upwards to finally cling to the ceiling.

Leaving the hall, a short walk took us to a nearby garden, where stag beetle mark-release-recapture fieldwork had been carried out in 2006 and was ongoing in 2007 in parallel with radio-tracking the insect. In the garden, a male beetle was radio-tracked to its hiding place under a pile of dead branches, from where it was extracted to examine the transmitter attached to its pronotum. Shortly after, another male beetle, this time marked, but without a transmitter, was recaptured and recorded, having been found under a large log, Then, at almost 22:00, there was great excitement when we were able to ‘net’ an unmarked male in flight, which provided the opportunity for members of the group to weigh, measure, mark and release a beetle (weight 2.38g, length 39mm excluding the ‘antlers’). Beetle ‘finds’ concluded at 22:10 with the capture of second unmarked male at the base of a tree. This too, was duly weighed, measured, marked and released (weight 4.04g, length 45mm). At 10:15 we left the garden well satisfied with our evening’s observations of stag beetle activity.

Although the number attending was not high, the meeting was very successful and was enjoyed by all.

Thanks are due to John Blackmore for arranging the village hall facilities. To Mike Ewart for arranging the loan of the digital projector and loading the presentation data onto the laptop, to John Standeven for operating the digital equipment, and to Bob Mawkes, who kindly allowed the group to invade his garden. Last but not least, I am grateful to those who, following the meeting, sent me their stag beetle records over the rest of the season.

Colin Hawes

Lead for the Stag Beetle Biodiversity Action Plan in Suffolk
October 2007

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23rd June 2007 DRAGONFLY AND BUTTERFLY WALK, Minsmere RSPB

Seven expectant folk had ignored the forecast of rain and fortunately, the weather was reasonable until the end of the walk. The main target was Norfolk Hawker, a species that has become established on the reserve in recent years. We were not disappointed: everyone enjoyed excellent views of three individuals on the loop around the woodland and wetland edge. A variety of other common dragonfly, damselfly and butterfly species were encountered despite the rather dull conditions.

Robin Harvey

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AUGUST 5th 2007 FIELD MEETING IN DUNWICH FOREST

Seven members of SNS met in the forest car park, near to “Bridge nursery” tea room, grid ref TM467710. Weather conditions were, for a change, ideal. Our walk was to take us through the forest rides, to the bird hide situated on the northern edge of the forest at the junction with the Walberswick reed bed, opposite Westwood Lodge.

The wide forest rides, drenched with sunshine, proved to be very conducive to insect life in general. Very evident, owing to their presence in large numbers, were the dragonflies. Common Darter was perhaps the most numerous species recorded; flying at a rather greater height were Migrant Hawkers, seemingly in larger numbers than they were last year in this locality. Ruddy Darters were less numerous than Common Darters (the two species were easily separated by the rather brighter red abdomen, terminating in a club shaped expansion in the males). A few examples of the large Southern Hawker were spotted, as they dashed up and down the forest rides seeking prey.

Having our butterfly recorder with us proved a real bonus (thanks Rob), and as would be expected, a respectable number of nineteen butterfly species were recorded, but all in low numbers. The complete absence of Small Tortoiseshell went to prove that this summer had not been a good one for butterfly species in general. The species list is:- Small Skipper, Large Skipper, Large White, Small White, Green-veined White, Small Copper, Brown Argus, Common Blue, Holly Blue (three individuals seen), White Admiral (one rather battered example flitting through the sun dappled woodland), Painted Lady, Red Admiral, Peacock, Comma, Speckled Wood, Gatekeeper, Grayling, Meadow Brown, Ringlet.

The sunlit, compacted soil of the forest track was suitable a habitat for the Red data book digger wasp, the Bee-wolf to excavate its burrows. (This status must surely be under revision, as this species has become so widespread in suitable habitat). On the path near the hide a fine example of the Large Emerald moth was found, and a fast flying male Oak Eggar moth was seen briefly as it flew between the conifers.

Some time was spent in the bird hide, but it was rather disappointing as the birds had decided to be elsewhere.

Some sweeping was carried out on the way back to the car park, and several species of cricket were found. The Dark Bush-Cricket was most numerous, and this caused some puzzlement as some of the individuals were of variable colour. The most uncommon species, the Long-winged Cone-head, of which we found a single female, was perhaps one of the finds of the day, as it is a recent addition to the Suffolk list. The females are easily separated from those of the more abundant Shortwinged Cone-head which we found to be plentiful, in that the ovipositor of the former is long and almost straight, whereas in the latter it is rather stouter and upcurved. Several Roesel’s Bush-crickets were found, this being easily distinguished by having a cream-coloured margin to the pronotum. Speckled Bush-crickets were numerous, and a few specimens of the Oak Bush-cricket were seen.

Hemiptera were very scarce and only one species of note was found, Neottiglossa pusilla (sorry, this has no common name), another record for an under recorded species for the county.

It was a very enjoyable day; thanks to all the participants.

Nigel Cuming

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