SPECIES CHAMPIONS

• Chalkhill Blue - Nick Ballard
• White Admiral - Vince Lea
• Wall Brown - Louise Bacon
• Black Hairstreak - Robin Field

What are 'Species Champions'?

Species Champions is all about improving our knowledge of the chosen species which, in turn, may be used to guide conservation programmes to benefit the species.The idea has been proposed by Butterfly Conservation as a means by which Branches can target particular species of local concern.These may be species which are nationally declining, which may have action plans already, or they may be species which are only of local concern.

Although a single-species habitat conservation plans would be unusual, a sound understanding of the requirements of a particular species can be invaluable when producing a site or habitat land management plan. Such a plan can then provide for the needs of a whole range of taxa - mammals, birds and invertebrates.

A 'Species Champion' is someone who acts as a central co-ordinator for activities which help in the conservation of that particular species.

By focussing on a single species, the Species Champion can provide a summary of the current state of knowledge of distribution, population trends, and so on to other branch members and individuals who may wish to help in surveying for additional records. In this respect, we need to consider eggs, larvae, pupae and habitats as well as adults.

'Champions' will also try to ensure that all likely sites are visited at appropriate times to try to draw up a good picture of the status of these butterflies in our area. We hope that the data collected will help us to understand the reasons for the status of these insects and if good sites are found enable us to open dialogue with land owners to try to ensure that areas are conserved or developed to help the butterflies found there.

What it takes to be a 'Species Champion'

Champions don't need to be an expert already, just reasonably interested in a particular species and a willingness to learn more! There are experts within the Branch who are more than happy to impart the basic knowledge and provide avenues fore further information. Howver, they are thin on the ground and already heavily committed, so they are unlikely to be able to add this additional role to their portfolio. Hence the need for extra volunteers.

Val Perrin, the Branch's Survey Officer, has identified nine species as being important in the local context. Some of the species have long been restricted or rare in our area, others are known to be in decline. To date, four people have volunteered to be a 'champion' which leaves us looking for a further five.
If you feel that you might be able to help or would simply like to know a little more about what it involves, please contact Val Perrin (details on the Committee page).

 

Species Champions

Species1	'Champion'	Telephone	Email
Chalkhill Blue (Polyommatus coridon)	Nick Ballard	N/a
White Admiral (Limenitis camilla)	Vince Lea	01223 263962
Wall Brown (Lasiommata megera)	Louise Bacon	01223 263962
Black Hairstreak (Satyrium pruni)	Robin Field	01604 844927
Heath Fritillary (Melitaea athalia)	Position Vacant	-	-
Small Blue (Cupido minimus)	Position Vacant	-	-
Dingy Skipper (Erynnis tages)	Position Vacant	-	-
Grizzled Skipper (Pyrgus malvae)	Position Vacant	-	-
Grayling (Hipparchia semele)	Position Vacant	-	-

¹ Click on name to see detailed species information

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Chalkhill Blue

At the Declining Species Workshop (delivered at the Branch's 2005 AGM), two presentations were given on this species,

• a brief resumé of the situation in our two counties and the national picture from Val Perrin,
and
• a more detailed presentation by John Dawson on his many years of monitoring and conservation work on the Devil’s Dyke, which is now without doubt our premiere site for this species and one of the best sites in the country.

Val explained that, nationally, this is a ‘Species of Conservation Concern’, with a restricted range due to habitat requirements; it is restricted to chalk and limestone grassland in southern England, Cambs colonies are at northern edge of their range. The range is declining in some areas, but in Cambridgeshire it is doing well where it occurs but there are very few known sites. It has been recorded occasionally in Essex but there is no suitable habitat for a colony, and these sightings are considered to be wandering individuals, the males in particular being known to travel some distances in good years.

Cambridgeshire has three (and-a-bit) sites:

1. Devil’s Dyke (Grid ref: TL614618)
2. Barnack Hills and Holes (Grid ref: TF072045)
3. Fleam Dyke (Grid ref: TL548541)
4. Therfield Heath (Grid ref: TL336401) (colony is in Herts but some adults cross the Cambs border)

Behaviour & ecology

	Chalkhill Blue
The sole foodplant is Horseshoe Vetch, and we could benefit from more understanding of the foodplant ecology. Eggs are laid singly on foodplant but often drop off and overwinter on the ground nearby. The larvae and pupae are tended by ants. This species lives in discrete colonies, but some adult males are mobile, seen up to 20km from known colonies.
	© Photo: Vince Lea

Habitat requirements

The essential requirement is Chalk grassland with abundant foodplant. The ideal sward height is 2-6 cm during the flight period, which can be achieved through grazing or cutting. Some taller grasses / scrub are necessary for roosting / shelter. Horseshoe vetch rapidly disappears from neglected swards, and is slow to return, therefore continuous conservation work is essential to maintain optimal habitat condition for butterfly.

Monitoring

• Devil’s Dyke – transect by Sharon Hearle at July Course but other sections not monitored
• Fleam Dyke – newly established colony – no formal monitoring yet (see separate article by Roger Lemon)
• Barnack H&H – no formal monitoring?

It was pointed out from the floor that in fact a regular transect operates at Barnack through the Centre for Ecology & Hydrology (CEH) ‘Butterfly Monitoring Scheme’ (BMS). This is essentially the same methodology as used by Buttefly Conservation for transect recording, and it is hoped that soon the two sets of data will be merged.
General information on the Barnack Hills site is now available on the BMS website and the Chalkhill Blue data can be found here.

Up to date details of the Devils Dyke transect and the Fleam Dyke discovery were published in newsletters 46 & 48, so it was nice to hear more historic background to the Devil’s Dyke colony from John Dawson, who, more than anyone else, has helped to save this site for the species. It would be nice if we could learn from this experience and achieve the same results for the nascent colony on Fleam Dyke!

John showed many slides of the species at Devils Dyke, the habitat which it favours, and the all-important work parties that have done so much to help this species recover by removing shade and maintaining a short diverse sward. There were helpful tips on finding the species too, with mention of favoured nectar plants for instance. While Knapweed can be very good, the drab brown flowers of Carline Thistle are a real draw, but unfortunately the highest numbers of males are most likely to be found on dog faeces!

Jack Harrison maintains an excellent website covering the essential information regarding this species at http://tinyurl.com/2g6r53

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White Admiral

The following text appeared in Newsletter No. 49 and is a summary of one of various talks given at our Declining Species workshop following the 2005 AGM.

Vince Lea gave a short talk on the White Admiral which has been included in the Species Champions set on account of the very small number of sites where it has been recorded. This is shown in the national distribution map below, suggesting that Cambs & Essex seem to be a ‘black hole’ as far as this species is concerned.

	White Admiral © photo: Vince Lea

Population trends

Butterfly Monitoring Scheme and BC transect data point to a National Decline in numbers at sites; Stour Wood in Essex, however, appears to be bucking this trend with a steady increase in numbers on transect counts. It has had recent peak counts of 27 individuals over a transect season. This compares with Monks Wood, in Cambs, which averages less than two sightings on transect most years and is more typical of the national picture. At the same time, the Millenium atlas shows a range expansion to the north. In 2005 it was recorded in Cheshire, and reports suggest many new sites are being colonised in neighbouring counties such as Norfolk & Suffolk. So there is a strong possibility that a concerted effort could find more sites for this beautiful species.

Although much easier to see and identify than the Black Hairstreak, it does have similar problems of low densities and a shortish peak flight time so small colonies are easily missed if not searched at the right time.

Trend data on emergence shows a lot of variability, so a network of interested parties co—ordinated by the species champion through the website would be an ideal way to catch the peak flight period, and also to catch the occasional 2nd brood that emerges more and more regularly in September. Evidence suggests early July is most reliable peak flight period, but some years peak is late June and it does seem to be getting earlier!

Sites

Stour Wood is the best known site, while near Colchester Friday Wood is good and Donyland Woods have regular sightings. Brampton Wood is the best Cambs site, with maxima over 10 and has recently had a transect count established.

Monks Wood, Castor Hanglands, Bevills Wood, and Holme Fen in north Cambs also record the butterfly from time to time.
Individuals can occasionally turn up anywhere, illustrating this species’ potential to colonise suitable new sites with the right combination of abundant honeysuckle growing in shady parts of woodland with nearby abundant nectar supplies from plants such as bramble. It would be worth checking any such wood, but particularly if in an area near other colonies.

Click here to see the report of the July 06 Stour Wood visit.

What should we do?

• Expand our survey efforts, preferably in a co-ordinated way based on potential good areas. This can be helped by identifying potential sites based on habitat - study maps, etc. and visit in winter to check for Honeysuckle and good rides.
• Extend the search season by looking for feeding signs e.g.nibbled honeysuckle - late Summer and again in Spring.
• Promote White Admiral needs at sites where conservation activities may be detrimental (e.g. stop the removal of shaded honeysuckle).
• Organise visits to good sites to show this species to members - promote the potential of woodlands for butterflies.

For further details or if you would like to help please contact:

Vince Lea

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Wall Brown

Introduction

We were fortunate to have Rebecca Harker was our first speaker at our Declining Species Workshop following our AGM in 2005. Rebecca has been carrying out PhD research on the Wall Brown at Oxford Brookes University, supervised by Dr Tim Shreeve, who also came to the meeting and provided useful contributions to the many lively discussions that were held throughout the afternoon. Her talk was a summary of her findings so far into the specific microhabitat requirements of the species.

	Wall Brown
Although still considered a widespread species (there were sightings from a number of sites in Cambridgeshire last year for example - Ed.) the Wall has undergone an extraordinary collapse in its distribution in central and southern England, with a contraction to coastal and northern sites. There have been many local extinctions across its range - it is one the most rapidly declining UK species.
	© Photo: Vince Lea

The research presented by Rebecca has followed a number of different approaches including intensive transect surveys on two contrasting sites (downland and coastal), with detailed observations on the microhabitat used by the individuals recorded.

Rebecca has found that a crucial component of the habitat required by Walls is bare ground or similar open substrate on which they can bask. This habit is, of course, the reason for the Wall’s common name. The Wall on the downland site was overwhelmingly associated with the bare chalk of footpaths across the site, while on the coastal site it showed a strong affinity for the wooden steps that had been built through the dunes. There is more work to be carried out, including an analysis of a large number of volunteers’ surveys on the habitat composition of sites with current or extinct populations of Wall. But the general message is fairly clear that this species needs a lot of bare ground to maintain viable populations. This is related to the high energy chasing behaviour of territorial males, which need to produce high body temperatures in order to react to passing intruding males or potential mates.

Following the meeting, Louise Bacon volunteered to be 'Species Champion' for the Wall.

Louise Bacon would like to know where there are colonies in the county still in existence.
We now know that they seem to need bare ground as a place to bask, especially at inland sites. This is down to the recent research by Rebecca Harker & Tim Shreeve. So, this seems to be a good starting point for finding colonies.

Do you have near you old railway, disused sand/gravel workings? Other post-industrial sites where there is some bare ground or sparsely vegetated areas?

If so, how about going out to have a look for the Wall, now, and again in late July - August. The second generation always seems to be better than the first. They are out now at Devils Dyke and in the Brick Pits around Peterborough, but where else are they? If you find one, or are keen to survey specific sites, please contact Louise.

Louise Bacon

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Black Hairstreak

At our Declining Species Workshop (held after the Branch's 2005 AGM), Robin Field gave a brief mention of the Black Hairstreak.

This is one of Britain's rarest butterflies and therefore the few colonies we have in Cambridgeshire are highly significant. In our branch, it is confined to woods on clay soils in the NW of Cambs and the national distribution stretches a little further north into Northamptonshire and south-west to Oxfordshire. The best known sites we have are Monks Wood and Brampton Wood. It has been recorded sporadically from several other sites, and it has the potential to exist undetected at many others, so the first priority is to survey for it in likely areas.

Black Hairstreak
	As with all the Hairstreaks, one of the problems surveying this species is its elusiveness in the field. The Black Hairstreak is particularly difficult in this respect as it has a very short flight season, around late June, only flies briefly during the middle of the day and then mostly around the tops of dense stands of its foodplant, blackthorn. Furthermore, there are rarely more than a handful of individuals present at good sites.
© Photo: Vince Lea

One possible method of surveying for it is therefore to search for the eggs, which are dormant through the winter on the twigs of blackthorn. Although notoriously hard to find, this aspect of its ecology at least offers several months when the butterfly can be sought, between October and April, and eggs are far more numerous than adults.

Training in egg hunting was offered to attendees of the AGM who signed a contact sheet if interested. Once a few of the committee have learnt the art themselves, there will be a training day for those who expressed interest. This is likely to be in late February, so there is still time to register your interest if you would like to come along. Contact Robin Field (details below) as he is going to Champion this species. It is hoped that trained individuals will go on to search for the eggs in March and again in the autumn and winter 2006-7 if the method appears suitable.

We have some funding to support research into this and the other Hairstreak species.
Take a look at our Hairstreak Project page as well.

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November 2006 Update

At the Branch Members' day following the AGM held on Saturday 4th November 2006, Robin Field gave a short but comprehensive presentation on all the work that has been undetaken to date by the Branch as part of its Hairstreal Project.

Black Hairstreak Satyrium pruni in Cambridgeshire

Helping Hairstreaks funded by ‘Awards for All’ Grant

Introduction

• The Black Hairstreak is one of the UK’s most elusive butterflies found exclusively in Blackthorn Prunus spinosa thickets in a small part of the East Midlands.
• The adults reside in the canopy of trees and dense scrub, feeding on honeydew secreted by aphids and rarely descending. They are at their peak of activity from mid-June to mid-July.
• The species UK BAP status is a ‘Species of Conservation Concern’ as it has seen a steady decline during the twentieth century and is now reduced to around 45 sites.

The 2006 Survey	Black Hairstreak
Egg surveys at Monks Wood and Brampton Wood in Jan/Feb 2006. Habitat survey in late April and early May when Blackthorn in flower. Training session for adult survey at Glapthorn. Adult survey of the main sites once butterfly was known to be on wing. Timed counts at Aversley Wood and Brampton Wood. Field trip at Brampton Wood. Revisiting main sites three times where possible. Visits to other woods suggested as suitable by Thomas (1975) if habitat still remained. Transects at Monks Wood and Bevill’s Wood (normal UKBMS) plus other counts at Monks Wood and Brampton Wood.
	© Photo: Nick Greatorex-Davis

The Results

• Egg survey – none found
• Habitat survey – each wood (except Brampton, Monks & Bevill’s Wood) scored using size, distance, previous records, habitat type and amount of habitat.
• Top scores Castor Hanglands 81/100, Warboys & Wistow 72/100 and Bedford Purlieus 56/100 Adult Surveys.
• Training session at Glapthorn; over 50 observations of Black Hairstreak adults including two mating.
• Field trip at Brampton Wood; over 40 adults seen at 5 different sites across the wood; 91 seen on timed count, over double most ever seen plus adults recorded on 3 other occasions.
• Monks & Bevill’s Wood transects; adults seen on 2 occasions on each transect plus approx 50 seen in Monks Wood in one lunch hour (observer NGD).
• Castor Hanglands; 13 seen at 4 sites, one of which was a new record.
• Bedford Purlieus; 15 seen at 3 sites, first records for 40 years.

Conclusion

• 5 definite colonies (Monks, Bevill’s, Brampton Woods, Bedford Purlieus, & Castor Hanglands) plus 1 possible (Warboys & Wistow) ( 4 + 4 in the 1970’s).
• Lost at Orton and Aversley Woods due to lack of suitable habitat.
• Bevill’s Wood recolonised naturally, one of the first every recorded recolonisations.
• 2006 best year for adults since records started.

The Future

• More survey work required at Bedford Purlieus and Castor Hanglands to find extent of colony.
• Establish a monitoring programme for all sites with known colonies.
• Habitat management required at Aversley Wood to try to restore suitable habitat.
• Habitat management required at Warboys & Wistow Woods to try to retain suitable habitat.
• Check remainder of suitable woodlands.

Thanks are due to the following:

• National Lottery ‘Awards for All Grant’ for part funding the work.
• Surveyors – V Perrin, S Hearle, B Dickerson, L Bacon, V Lea, N Greatorex-Davies, A J Roberts & M Anderson.
• Glapthorn Cow Pastures wardens and volunteers for training.

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February 2006 Update

Sharon Hearle, along with 5 members of the committee, conducted two afternoons of fieldwork to locate black hairstreak eggs in the two known largest colonies of this insect. Each search was 3 hours of intensive searching in the areas where most adults were seen over the past couple of years, and no hairstreak eggs were found.

Eggs of two moth species were found, so egg-hunting is not impossible!

We have also consulted people in neigbouring counties and no-one has had any success with eggs outside of the Upper Thames Branch. Therefore, we would like to thank Sharon, Vince, Louise, Tony, Robin and Val for subjecting themselves to several cold hours spent in blackthorn over the past two weeks, and to thank Nick Greatorex-Davies and Barry Dickerson for providing location information.

So, to all of you who volunteered to be trained to find eggs, we would like to say that we do not feel it is worthwhile pursuing this at present, but Robin will be in touch with you all about searching for adults later in the year.

For further details or if you would like to help, please contact:

Robin Field 166 Sherwood Avenue NORTHAMPTON Northamptonshire NN2 8TE Tel: 01604 844927

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Grayling

Val Perrin gave a brief account of the Grayling situation, based on records submitted and known details of the national situation. It is widespread in coastal regions and southern heaths around the UK, but declining in many areas, particularly inland. It has quite cryptic coloration – easily overlooked – but the species status in Essex is unknown; possibly lost. There have been no recent records for Cambridgeshire.

Ecology / habitat

Grayling
	Coastal colonies are found on dunes, saltmarsh, undercliffs, while inland dry heathland, old quarries, former industrial sites (old spoil heaps) are utilised. As with all the ‘Browns’ the larvae feed on grasses. Grayling are known to utilise sheep’s-fescue, other bents and fescues. Larvae feed nocturnally, and overwinter in tussocks. The adults spend less time nectaring than other butterflies. Males are territorial. Colonies can range in size from 50 – 1000’s, but they are rarely seen away from breeding areas. It is a very variable species – several distinct races in GB.
© Photo: Tony Moverley

Last Essex records :

• Grays chalk quarry 2001
• Dengie coast 1998
• Millwood Pit, Grays 1997
Middlewick ranges, Colchester 1991
• (1 or 2 scattered records : Great Easton, Great Oakley)

The most likely chance of finding this species will be on coastal sites in Essex and an intensive effort to find this species would be very welcome.