Having achieved the first objective of gaining a better understanding of the ecological requirements of the butterfly and having laid the basis of good management within the Grafton Wood SSSI, it was time to begin the next chapter of discovery. Just how widespread was the Brown Hairstreak in east Worcestershire? It was time to find out. During the winter of 1993/4 a survey was carried out, with financial support from English Nature, of hedgerows and woodland within the triangle of Grafton Wood, Hill Wood and Quartern Ash Wood. This proved in many ways a depressing experience. Hedgerows generally had been subject to rigorous trimming which had often reduced the height of the hedges to only a fraction of their pre-cut size. In some instances, there was evidence of whole hedge removal while, in other cases, hedges had been reduced to just a few inches from the ground. Nevertheless, eggs were found and by the end of the survey we were able to report that presence of the butterfly was confirmed in no fewer than 16 1km squares suggesting a wider distribution in the county than had been previously assumed. Furthermore, the survey suggested that the potential range of the butterfly was considerably greater but that generally unsympathetic hedgerow management was proving a major constraint.

In order to address this issue, the decision was taken the following year to try approaching local farmers to encourage them to join the Hedgerow Incentive Scheme which had been recently launched as part of Countryside Stewardship. The scheme offered payments to landowners for the restoration and sympathetic management of hedgerows. In practice, the financial incentives offered proved unattractive to farmers and, although some useful contacts were made and a number of landowners expressed interest in the Brown Hairstreak, none were persuaded to enter the scheme. A useful by-product of this work, however, was the preparation of a glossy leaflet which was aimed at promoting awareness of the Brown Hairstreak butterfly and providing management advice. The leaflets were provided to MAFF and also FWAG officers for local distribution and have since been reprinted.

Over the years, as time allowed, we continued to build up our knowledge of the distribution of the butterfly and by the beginning of 2004 we had recorded the butterfly in 37 1km squares (see map). Grafton Wood was still very much the centre of the butterfly’s distribution but, by now, we had found eggs as far north as Bradley Green, Naunton Beauchamp to the south, Inkberrow in the east and Earls Common to the west. In fact, 2004 proved to be quite a year of advancement for the Brown Hairstreak in Worcestershire. The appointment of Butterfly Conservation’s first regional staff the previous year had led to renewed efforts to engage with landowners and the local community in general. Contact with DEFRA, who had now taken on responsibility for the revised Countryside Stewardship scheme, proved invaluable and, for the first time, there was a means by which our egg data could be fed directly into management prescriptions on farmland. DEFRA staff agreed to consult Butterfly Conservation on all farm agreements and input our data onto their own GIS system. A joint training event attracted over 40 farmers who learned firsthand about the requirements of the Brown Hairstreak and Countryside Stewardship. Parallel to this, a successful application to the Lottery’s Awards for All scheme meant that a concerted effort could be made to involve the local community. New display boards were ordered and an interpretation panel was erected at the entrance to Grafton Wood nature reserve. Perhaps most significantly, a local Brown Hairstreak champion scheme was launched whereby local residents were invited to become involved in recording the butterfly and planting blackthorn on their own land. A regular email newsletter was started to keep people in touch with the latest sightings and a number of public events and activities were arranged. All of this was translated into increased recording effort so that by Spring 2005 the number of 1 km squares in which eggs had been discovered had grown to 54.

This upsurge in recording has continued during this current winter (2005-2006) and the number of known squares has now incredibly topped the hundred mark. For the first time, an egg has been discovered across the border into Warwickshire (the first record there for over thirty years) and eggs have been found in Trench Wood which is the first confirmed record of breeding at this site in over a hundred years! 

Like all detective stories, however, there are still many questions still to be resolved and even aspects of the butterfly’s life cycle are still not properly understood. This includes issues like the butterfly’s use of assembly trees. This is something that we have only just begun to study over the past two years. So far only a few trees have been identified, mostly hedgerow Ash trees but also prominent trees at the edge of woodland, and it is still uncertain whether the same trees are used consistently every year or indeed whether male butterflies remain loyal to the same tree throughout the flight season. There is also the mystery of pupation. Although a number of larvae have been followed over a period of weeks and we have been able to challenge the previously held view that caterpillars are only active around dusk, we have not so far been able to locate pupae. Opinions seem to differ as to the exact pupation site as so few have been found. On the ground within leaf litter or even below the earth seems most likely and it may be that, like the Purple Hairstreak, the pupa is associated with ants’ nests.

Perhaps the most fundamental question, however, is whether what we have seen particularly over the past two years in terms of new records is just a reflection of increased recording effort or represents a genuine expansion of range? It is difficult to be sure and probably the answer is a bit of both. Certainly, the local Brown Hairstreak Champions scheme together with the Vision Mapping project of the Worcestershire Biodiversity Partnership has recruited new recorders who have been trained and encouraged to search for eggs. It is also true that we have looked for eggs in areas where we would not even have considered looking five years ago and, each time we have been successful, it has encouraged us to widen our search area still further. I would like to feel, however, that the good management around the core area of Grafton Wood and nearby woods has helped to build up population numbers in a way that has aided dispersal. As far as the wider countryside is concerned, there is still a long way to go before Hairstreak-friendly hedgerow management becomes the norm but there is no doubt that our partnership with DEFRA particularly on the back of the new agri-environment scheme is bearing fruit and we are seeing increasing numbers of landowners joining the scheme. The new entry level stewardship scheme encourages rotational cutting of hedgerows while higher level stewardship includes specific management prescriptions for Brown Hairstreak which have been developed in association with Butterfly Conservation. This includes trimming each hedge in rotation no more than one year in three, allowing hedges to reach and maintain a minimum height and width of 2 metres, planting up gaps with at least 50% blackthorn and leaving a 2-6m wide margin alongside the hedgerow. Although primarily designed to benefit the Brown Hairstreak there is no doubt that many farmland birds, hedgerow plants and other insects will also gain from these changes.

Another training day in January 2006 held jointly with the Worcestershire Biodiversity Partnership attracted a further 25 local landowners to learn more about the new stewardship schemes. Already one of the farmers attending has been in touch to say he has found Brown Hairstreak eggs on his land and to ask for management advice. All this is excellent news, as is the announcement in the latest Worcestershire Wildlife Trust newsletter that the Forest of Feckenham has been designated as a priority conservation area within the county, which makes it the focus of future conservation action and land acquisition. The butterfly has now been recorded on five Trust reserves, including the new reserve at Humpy Meadows, within the area which is a good start. The Brown Hairstreak is very much the flagship species for this landscape based approach within the Forest of Feckenham as it is principally a farmland species dependent on a network of woodland, with interconnecting well managed hedgerows and herb-rich grasslands, if it is to thrive. There is no doubt that if we can improve its status through better hedgerow and woodland management, there will be benefits for many other forms of wildlife. This is an exciting project with lots of challenges but we have made a good start and Butterfly Conservation will be continuing to work closely with the Wildlife Trust in the months ahead to turn this vision into reality.

Undoubtedly, there are more locations for the Brown Hairstreak to be discovered and we are keen to encourage further recording. It would still, however, be a big surprise if there were modern records outside of a line joining Worcester-Pershore-Evesham-Redditch-Droitwich-Worcester but it would be nice to be proved wrong! Jack Green in his little booklet on Worcestershire’s butterflies lists the 10km squares SO84 and SO94 (both outside the current known range) as holding the butterfly but gives no further detail, although in his subsequent article for the Entomologists Record he refers to eggs being found at “a perimeter dispersal point on a disused airfield”! It is clues like this that help bring out the detective in all of us. If anyone is interested in finding out more, helping with future recording efforts or would like to be kept up to date with the unfolding Brown Hairstreak story via the email newsletter please get in touch.

References