BUTTERFLY WALKING - ITS HISTORY AND ORGANISATION
Readers of this, who have followed a good number of the walks, will probably soon notice a particularly interesting species. It can usually be seen between April and September and between 11.00 a.m. and 3.30 p.m. Its behaviour is a good key to its identification. It walks at a slow but steady rate with a clear sense of purpose, its eyes fixed on the ground ahead, and slightly to either side. Normally it pauses every so often to write things down on a clipboard, though it must be admitted that there is a rare subspecies which carries a small tape recorder and can be seen speaking into it as it ambles along. If stopped and engaged in polite conversation it is usually friendly, but can become tense if there appear to be clouds threatening to obscure the sun. It is a waste of time looking for this species on wet or cold days. It has spread quite quickly in the UK and is rumoured to be extending its range into British Commonwealth countries, and has recently begun to invade the EC via the Netherlands. This species is generally called the "Butterfly Walker", but it is on occasions referred to as a "Transect Walker" or a "Pollard Walker". This page will attempt to explain how and why this strange ritual of making walks to count butterflies has arisen and how the rules for carrying out walks work.Of course it is perfectly possible to just enjoy the walks on this website without bothering to investigate further; in the same way many people enjoy walking old Neolithic trackways or Roman roads without worrying much about the people who built them or their motives. However all the walks described are more than just pleasant routes which give walkers a chance to experience magnificent scenery and see interesting species; they all have a serious scientific purpose and this page aims to explain what that is.The first butterfly transect walk in Britain could be said to have taken place with a count around the rides of Monks Wood by Jeremy Thomas and Ernest Pollard in May 1973. The total count amounted to four Peacocks, one Speckled Wood and one Green-veined White. Of course, this was no more the beginning than Stephenson's Rocket was the start of the Steam Engine. The idea was planned at a gathering in Ernie Pollard's office at Monks Wood, the headquarters of the Institute of Terrestrial Ecology. Besides Ernie Pollard, whose name is often given to the walks, the planners were D.O. Elias, the Warden of Monks Wood, M.J. Skelton, working in the Biological Records Centre, and J.A. Thomas, at that time studying the Black Hairstreak in Monks Wood itself. The four planners naturally did not produce their ideas out of nothing. During the 1960's and 1970's Norman Moore, best known to natural history enthusiasts as the joint author of the Collins New Naturalist Series number 41 on Dragonflies, had made regular counts of butterflies along the edge of Monks Wood and his scheme was very much in the minds of the four planners. As is so often the case with the history of ideas, other workers, unknown at that particular time to the planners, had also been developing similar schemes. In particular, Ekholm had been using transect counts to monitor butterfly numbers in southern Finland for over twenty years.Like many of the best ideas in history, transect walking was devised to solve an immediate practical problem but later turned out to have much wider uses than could originally have been guessed. The original programme at Monks Wood was to find a method, which was relatively simple to use and which could record changes in numbers of butterflies on that particular Nature Reserve. Up until then the most favoured method was called "capture, mark, recapture". This involved catching a large number of a particular species of butterfly in one area, marking them with a small spot of paint and, on a later occasion, catching another sample. The proportion of marked individuals in the second catch could then be used to estimate the size of the population. However, although this method can produce fascinating information on numbers, births and death rates of butterflies, it is extremely demanding in terms of time and labour, and may alter the behaviour of the butterflies captured and so their chance of recapture. The idea of measuring fluctuations of butterfly numbers by walking a route and making regular counts of each species was clearly much less time consuming but would it be accurate? Careful trials carried out at Monks Wood comparing both methods showed a very high level of correlation and that, as long as the rules for doing the walks were obeyed, it made little difference, who was doing the walk. In fact the butterfly walks, though not of much use for measuring actual population sizes of different butterfly species, were probably much better for estimating changes in population size.Further pilot trials were carried out in 1974-5 using the Wardens of Nature Reserves and it soon became clear that the data made available was of great value to Nature Reserves. Because each count was divided into sections the Wardens could very quickly gain useful knowledge about the distribution of each species and when several years' totals became available they could tell whether the species was doing well.So in 1976 Ernie Pollard took the decision to set up a much wider scheme for the whole of Britain consisting of over 34 sites. Over the following years the numbers of sites increased to reach 80 in 1980. Finance came from the Institute of Terrestrial Ecology and the Nature Conservancy Council. The data was collected from the Wardens at the end of each year and fed into a computer at Monks Wood. In the following year a summary of the results was made available for the recorders and after 10 years the Nature Conservancy Council published the findings up to that point, in their Research and Survey in Nature Conservation Series Number 2 "Monitoring the Abundance of Butterflies 1976-85". It was now apparent that the scheme was doing much more than had originally been anticipated. From the individual Reserves' point of view they now had a valuable instrument for measuring how well they were conserving their butterflies. If everyone else's Chalkhill Blues were increasing and theirs were not, they could then be alerted into finding out why. From the national point of view the data being collected would clearly pick up any adverse trends in butterfly numbers much more quickly than the earlier Lepidoptera Recording Scheme, which had set out in 1976 to map the distribution of butterflies in Great Britain. The presence or absence of a species in a particular kilometre square on the map says nothing about the strength of the colony; by the next time surveying for the map had taken place, the colony could have disappeared. The arguments in favour of developing the transect walk recording scheme were strengthened by the revelations of the mapping scheme. Destruction of habitat was clearly confining rarer species to isolated pockets or Nature Reserves. The transect walks could reveal much more quickly when and if hitherto commoner species were about to go the same way. They could also help to ascertain how long the rarer species could remain in isolation and retain their viability as breeding colonies.Further developments on a global scale took the arguments in favour of developing the scheme beyond merely protecting British butterflies. The debate triggered off by Rachel Carson's "Silent Spring" in the 1960's posed the question of whether the world was facing an environmental pollution problem on such a scale that the species of man could be under threat. The butterfly counting scheme could act as a very useful early warning system. Butterflies and moths were an important part of the food chain, which led right up to Homo Sapiens itself. Lack's famous research on Robins for example revealed the necessity for a diet of about 1,000 caterpillars per day. If there were catastrophic drops in butterfly numbers then the warning bells could be rung more vigorously and there might still be time to act. By the 1980's yet another global scale development strengthened the case for the scheme at a vital time when government finance for projects which failed to prove clear short term practical benefits was being ruthlessly cut. The related but separate concepts of global warming and ozone depletion were born. Estimates of an increase in global temperatures from 1 to 4 degrees centigrade as a result of the "greenhouse effect" by the year 2050 were made. For Britain one scenario estimated a rise in mean temperature of around 3° Celsius and a change in mean rainfall of +/- 20%. Warnings of rising sea levels as polar ice caps melted were made. With a large proportion of their country either close to, or below, sea level the Netherlands Government in 1989 encouraged the establishment of a Butterfly Monitoring scheme similar to that of Monks Wood. In the same year the British system was extended further by the addition of another 25 transects to bring the total up to 95. The publication of "Monitoring Butterflies for Ecology and Conservation" by E. Pollard and T.J. Yates in 1993 showed the project to be alive, well and beginning to show results. Dorset became involved in this nationwide scheme of counting butterflies in three stages. Dorset counts were set up right from the start of the Monks Wood scheme. In 1976 walks were begun on Studland Heath National Nature Reserve and on Ballard Down near Swanage. In the following year another walk was started at the Radipole Lake RSPB Reserve near Weymouth. In all three Reserves the walks were carried out by professionals, either as in the case of Studland and Radipole by the Wardens or their assistants or, as in the case of Ballard Down, by research workers from the Institute of Terrestrial Ecology at Furzebrook near Wareham. Studland produced data on heathland species like Silver-studded Blue and Grayling and also on woodland species like Silver-washed Fritillary and White Admiral. Swanage covered downland butterflies like Adonis and Chalkhill Blues and Lulworth Skippers. Radipole proved to be useful for the recording of migrants with Clouded Yellows being recorded in 5 of the first 9 years of the scheme. These walks still continue and Ballard Down has been included in this book though it must be noted that, as it covers mostly privately farmed land, it has been considerably altered.The second stage for Dorset started when the Conservation Officer for the Dorset Trust for Nature Conservation (DTNC, now Dorset Wildlife Trust) wanted to find a clear method for monitoring the butterflies on the recently obtained Fontmell Down Reserve near Shaftesbury. In 1980 two members of the Fontmell Down Management Committee, a teacher (the author) and a night nurse, were joined by two other amateur entomologists, a retired lecturer in English, with a book on Malaysian butterflies to his credit, and a Church of England Chaplain, especially skilled on moths, to plan the walk route and collect the records. The first walk was carried out on April 3rd and recorded one Small Tortoiseshell and two Peacocks. This new walk marked a radical departure. DTNC Reserves had no full-time professional Wardens and were managed (and still are) by committees of amateurs under the guidance at that time of the one full-time professional Conservation Officer. An amateur with another job to do could not possibly spare the time to cope with the full quota of at least 26 walks required by the Monks Wood scheme. Thus was born the concept of the "Dad's Army" butterfly walk, carried out by a number of amateur volunteers and hopefully still reasonably accurate and useful because they followed the rules prescribed. The method seemed to work - the numbers of butterflies counted each week appeared to build up logically to a peak and then gradually diminish with a similar logic no matter which member of the "Dad's Army" had done the count. At the end of the first year the four walkers were slightly amazed to find that the Chalkhill Blue count for 1980 on Fontmell was 1,353, only slightly less than for the Meadow Brown! New walks in the North Dorset area soon followed: Hod Hill in 1982, Jerry's Hole and Sovell Down in 1985. As the number of walks grew, so did the number of walkers. Private sitting rooms burst at the seams with meetings of walkers looking at slides to aid identification, deciding who walked where and when and arguing about whether that butterfly in August could have been a Dingy Skipper. There was the nun who took excellent colour slides and walked in her black habit; the dentist from Pembrokeshire who had already written a guide to the butterflies of that area and who was rumoured to carry out butterfly walks while his patients waited in his surgery for their anaesthetic to take effect! It was in these days that the "market value" of retired walkers was first appreciated. Weekend walkers soon discovered that British Saturdays and Sundays were more often than not too rainy for walks. Telephone lines were frequently jammed by desperate pleas for retired colleagues to do last minute fill-ins.Meanwhile "Dad's Army" walks had spread to South, West and East Dorset. In 1982 a heathland walk at Tadnoll and in 1985 a woodland walk at Powerstock were inaugurated for the DTNC. Also in 1985 a walk on the Royal Army Ordnance base at West Moors got under way and was soon recording huge numbers of Silver-studded Blues. The growth in numbers and expertise of the amateur walkers were at all times encouraged by the professionals at Furzebrook Institute of Terrestrial Ecology who gave generously of their time for lectures and field days. The Dorset Environmental Records Centre, which had been set up in 1976, also gave a large amount of help in arranging field days for identification and study. The publication of "Butterflies of Dorset" by Jeremy Thomas and Nigel Webb in 1984 gave a welcome boost to the confidence of the "Dad's Army" walkers because it made use of some of their count data.The third stage of Dorset's involvement with butterfly walking came in the late 1980's with the formation of the Dorset Branch of Butterfly Conservation. The committee decided at an early stage that the mapping of Dorset's butterflies was being carried out more than adequately by the Dorset Environmental Record Centre. Members were encouraged to send in sightings to the centre in Dorchester but the main Society initiative was to be devoted to running and setting up more transect walks, and making the results available. In this way, while further walks were arranged for the DTNC, new ones were set up for the Woodland Trust at Duncliffe (1986) and Fifehead (1987), the Forestry Commission at Stubhampton Bottom (1985), the National Trust at Clubmens Down (1991), Badbury Rings (1992) and Pamphill (1992), Dorset County Council at Durlston (1989), and various private owners at Lydlinch (1987) and Wimborne St Giles (1994). The original four walkers on Fontmell had multiplied to well over one hundred and meetings in private sitting rooms had given way to gatherings in public halls. The Tadnoll group had meanwhile developed the technique of storing the results on computer. A network of computer operators was set up, linked to a master computer. The data from the original historical three professional walks as well as seven other walks, which had been set up like the one on the RSPB Reserve at Garston Wood, were invited to send in their records. Each year a summary of the Dorset transects was sent to the owners of the land and a report was published with the Butterfly Conservation Society's newsletter, picking out the key developments in the year. The whole scheme acquired a final booster when in 1989 Fontmell Down and Tadnoll were asked to contribute their records to the central scheme at Monks Wood. The list of transect walks in operation at present is shown below and a map of general distribution is here.
In 1994 discussions for further improvements were underway. In order to meet the growing number of requests for data the computer system needed to be improved and time and money for putting in the backlog of records from previous years was required. Requests, for information about particular species like the Grizzled Skipper and Dark Green Fritillary, for indexes to act as comparisons for other sites being monitored, for records to update the book on Butterflies of Dorset, and to help new road schemes to avoid sensitive areas, were mounting up and made this urgent. The original "Dad's Army" walk at Fontmell had been backed up by local weather figures. By using these in conjunction with the walk data interesting correlations between particular butterfly species and weather were emerging. An ambitious scheme for linking other walks to nearby weather stations was being planned. It had always been obvious that day flying moths ought also to be part of the count on walks. Lists were made of the moths most likely to be seen and plans were discussed for including them in the counts.So how can those who have tried out some of the walks on this website, found them interesting, and been persuaded by some of the arguments earlier in this chapter that their aims are worthwhile, get involved in this new folk movement? The first step is to choose the area, which is to be walked in, and the particular walks to be involved with. This can be done quite easily if some of the walks have been sampled. The table above shows the walks arranged in the four regions of Dorset. The map shows the locations of all the walks available. The next step is to get in touch with the Records Officer for the Dorset Branch of Butterfly Conservation, or check the Events Page, and find out when the Start of Season Planning Meeting for the area you are interested in is to be held. If you belong to Dorset Butterfly Conservation the dates of these meetings are shown in the Newsletter. Different areas of Dorset are organised in different ways. The method used in Shaftesbury by the North Dorset walkers is a common model. When you enter the hall where the meeting is held you will be confronted by a scene, which slightly resembles a market or the old London Stock Exchange. There are a large number of stalls at which different butterfly walks are "for sale". The "buyers" are moving around the stalls trying to buy in the weeks they want to walk. It should be explained that butterfly walkers have their own calendars just like Christians, Jews and Muslims. Readers who remember their school history may recall all the problems which arose when the Roman Christians quarrelled with the Celtic Christians about the date of Easter; or the inconvenience of being given two dates for the Russian Revolution - February or March 1917 - not for once because historians disagreed about when it was, but because it depended whose calendar you were using - Roman or Greek Orthodox! The butterfly walkers' calendar is shown below and it can be seen that it begins on April 1st and ends on September 29th. If you want to do a walk on May 7th this is called Week 6. This is because on average butterflies are most in evidence between April and September and it is statistically convenient to analyse the records into the 26 weeks of the walking season.
| WALKING PLAN FOR THE YEAR The plan below shows the period of time during which transect walking takes place. Note how each walking week begins on whichever day of the week April 1 happens to fall; the walking week does not automatically start on each Saturday or Sunday.
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If you sit back and watch this strange folk ceremony you will notice that the buyers are following basically one of two strategies. Some just join one queue. These are the equivalent of those male butterflies, who hope to find a mate by perching on one spot for most of the day. This group enjoy visiting just one habitat during the year and observing closely how it changes over the seasons, how as the year progresses different species of butterflies and flowers come and go. The other group of people can be seen flitting from queue to queue and are the equivalent of the male butterfly patrollers who fly perpetually in search of mates. These people enjoy visiting lots of different habitats and perhaps have particular species of butterfly they would like to watch. They have probably used a butterfly flight timetable, like the one and worked out that, for example, the Duke of Burgundy flies between weeks 7 and 10, and are hoping to find a blank walk space for Fontmell Down, where they know it can be seen, in at least one of those weeks. Before you join the market you would do well to consider which strategy is the one for you; though remember that you can, like the Speckled Wood, which is a percher on sunny days and a patroller on warm sunless days, combine both! If you put yourself briefly in the place of the sellers, sitting behind their stalls, you will appreciate that their objective is to "sell" all their weeks; if they fail to do so they will have gaps which they will either have to fill themselves or spend many hours on the phone looking, to switch to medical terminology, for a "locum".Suppose you are successful in your market negotiations, you should be given four things. First a supply of blank walk sheets. The walk is divided into numbered sections, which correspond to the numbers on top of the walk sheet. Each section is usually a different habitat - for example woodland, scrub, grassland. Second a map of the walk like the ones in the walk descriptions on this website. Third a copy of the walking rules. Fourth a copy of the previous year's "results" set out by species and weeks. The blank walk sheets with the species listed down the left hand side might bring about a momentary feeling of panic about what you have let yourself in for. You can identify Peacocks but what about the other species? Keep calm and remember that doing a butterfly walk is the easiest way of learning your species that there is, and that butterflies, with only at the most around thirty five species per walk, are by far the simplest group to work on. You will need a good reference book.. If you are walking on only one of the walks, which is the most sensible strategy for beginners, you can start by using the previous year's results to work out what you are likely to see on your first visit. New species come in gradually as the year progresses so you will only have to cope with a few at a time. The Events Calendar in Dorset Butterfly Conservation News lists days on which experts help with identification. Guidance will also probably be given on the more difficult species at the start and end of year meetings. As the last resort there is always the telephone to contact your walk organiser (the "seller" at the "market") who can probably help with a query about what you saw.Before you set out on your first butterfly walk of the year you will find it helpful to join the start of the season guided "tour" which will point out any route difficulties which might not be clear from the map. This concerns especially the precise point at which sections change. You will also need to obtain a simple thermometer, which gives Celsius (°C) readings, and a clipboard, to hold your recording form and map, makes life simpler. At the start of the walk find a bush or other shade for the thermometer and leave it behind to pick up at the end of the walk. Fill in the top part of the recording form, and the date and start time. Begin the walk and make a pencil mark against the appropriate species for each one seen. Some of the butterflies, like the Brimstone, have a diagonal line to enable separate totals for males and females to be entered. As you walk, check that you are following the correct techniques shown in the rules. It is very important that you do not try to count all the butterflies you see but only those within an imaginary box five metres around you. It is usually best to ignore butterflies, which come in from behind unless they are a species you have not yet recorded. This is to avoid double counting. At the end of each section of the walk remember to fill in the time, and the percentage of time when there was sunshine. If the sun casts a shadow it is counted as out. When the whole walk has been completed do not forget to do the following:
- Find your thermometer and enter the reading in the End Temperature column. Many walkers forget their thermometers and it is soon going to reach the stage where a living can be made from picking up lost ones like golf balls!
- Complete the Wind Force column using the Beaufort Wind Scale in Figure 5.
- Add up the pencil marks for each species in each section and fill in the section total clearly.
- Add up the total numbers for each species and fill in.
- Work out the total percentage of sun time using the section percentages to help.
- Write any additional data on the back of the recording sheet. This could be observations about what butterflies were feeding on; any records of egg laying, comments on weather before or during the walk, evidence of recent management, scrub cutting, grazing.
- Send your record sheet to the walk organiser as soon as possible.
On no account be put off by the apparently complicated rules. They are the minimum necessary to ensure that the walks are comparable no matter who does the walking. The Dorset Branch issues a helpful guide to the rules for walking entitled "Counting Dorset's Butterflies" which can be carried around. People walk because they find it enjoyable and the form filling soon becomes second nature. In Winter the regions put on an end of season meeting which gives walkers a chance to meet, chat about the year's highs and lows, collect the results of the walks and discuss problems of identification. For those who need something to take their minds off the long winter months there are numerous butterfly walk related tasks to keep them occupied. There are computer records to be typed in, reports to the various owners of the land over which the walks pass to be researched, written and distributed, with unending scope for investigation into the mounting body of data that is accumulating. In no time at all it is March and the season is about to begin with another butterfly walkers' "market".Naturally if you are going to devote some time and energy in making butterfly walks you are entitled to enquire what purpose this is serving apart, of course, from keeping you occupied and fit. So far the walks have not been running long enough to answer the "big" questions like, is there really any sign of global warming? One interesting change exposed by the national monitoring system run from Monks Wood is that the range and flight period of the Hedge Brown (Gatekeeper) have both been expanding. One estimate is that it has moved northwards by about fifty kilometres since 1970. Using 35 of the sites with records in the Monks Wood database it was found that since 1976 the mean flight period had lengthened by about five days and that there was also a trend to earlier emergence. It is not thought that this is necessarily evidence of global warming but it does show how the data being collected can be used to pick up changes. There are all sorts of possible future scenarios being discussed. Droughts could put shade loving butterflies like the Speckled Wood and Green-veined White at risk. Rising temperatures could make it possible for butterflies which can only breed at present on short turfed south facing slopes, to move to previously cooler slopes with longer grass. This would show up quite clearly on a Reserve like Fontmell Down where the section counts of Adonis Blue and Silver-spotted Skipper would start to change. Northern butterflies like Large Heath and Mountain Ringlet, might become more and more isolated as areas of upland bogs and mountain grassland become restricted. In southern Europe the Peacock has two broods. Might this start to happen in Britain? Similarly in Scotland the Common Blue has only one brood per year compared to southern England's two. Global warming might begin to show itself if Scottish Common Blues start imitating English ones. Finally there is always the exciting possibility that European butterflies like the Map might begin to establish themselves.However even though it is too soon for the data to throw light on the "big" issues it is already becoming invaluable for solving more local ones. For instance, the sections of the Fontmell Down walk have been classified into four groups: south-facing grassland, north-facing grassland, scrub and longer grass, and wood. The figures shows clearly that Silver-spotted Skippers and Adonis Blues have a definite preference for south-facing grassland; Chalkhill Blues also prefer south-facing grassland, but are more likely to appear on the north-facing slopes. On the other hand Marbled Whites definitely prefer the north-facing slopes and scrubby areas. Dukes of Burgundy have a different preference system and are almost entirely to be found in the scrub with long grass areas. As might be expected, the Speckled Wood is more addicted to the woodland sections. The management committee would be interested to know whether there had been any changes between 1980 and 2000. On the whole things have remained fairly stable but two developments might cause some alarm. Silver-spotted Skippers seem to have lost their slight foothold on north-facing downland, while Speckled Woods seem to be favouring it more. Does this mean that the downland is getting too scrubby? The Duke of Burgundy appears to have retreated altogether from the south-facing down; have there been any management changes which could explain this? The answers to these two questions are not simple; but the data has at least drawn attention to possible changes and the situation can be watched carefully. The figures also suggests a strange contradiction: if Adonis Blues and Silver-spotted Skippers are short grass species, why do quite a large proportion seem to be flying in areas of scrub and long grass? This question can be answered by the notes which careful walkers have added to their reports. Section 5 in August is covered with Marjoram which sucks in butterflies of all shapes, colours and sizes no matter whether their usual haunts are woods or short grass.Imagine you are on the management of the FontmellDown Reserve committee in 1983. The Chalkhill Blue, for which the Reserve was originally purchased, has had a catastrophic drop in numbers. The actual numbers, 1,353 counted in 1980 down to only 40 in 1983. Is the management to blame? A check on the grazing routines shows that nothing different is being done and the grass heights which are measured regularly show no obvious changes. However the Index from the National Monitoring Scheme at Monks Wood indicates that most other sites have been improving since 1981! Of course with hindsight, there was no cause for concern and the numbers at Fontmell began to recover from 1984 and went on in 1992 to move to an even higher peak than 1980 and to keep more or less in line with the National Index. By themselves the walk figures could not solve the problem of why Chalkhill Blue numbers fell and rose in that way, but used in conjunction with the weather data collected from the local station in the village of Fontmell Magna they could provide some clues. Over the 22 years since butterfly walks started the average yearly count works out at 700. The years 1980 and 1989-1994 had above average counts, the years 1981-1988 below average. Weather data collected shows the rainfall in May and June presented in the same way. It is important to understand that the Chalkhill Blue goes through the winter as an egg. In the spring the young caterpillar hatches out and by May and June is feeding up as quickly as possible and changing into a chrysalis. Data seems to show that successive years of higher than average rainfall in May and June reduce the numbers of Chalkhill Blue, which emerge as adult insects waiting to be counted by the walkers. Conversely, lower than average rainfall in 1988-1992 led to an increase in numbers. Further walk and weather figures will show whether this correlation holds but will not explain why the amount of rain is so vital. It may be that the wetter weather retards the growth of caterpillars and makes them more vulnerable to predators or perhaps it encourages the growths of moulds, which raise caterpillar death rates. Further research will be required but without the walk figures, the problem could not be positively formulated in the first place. A final way in which butterfly walk data can be invaluable for the management of Reserves is when discussion begins on possible changes to a part of the area. At Fontmell Down a piece of woodland called Cat's Whisker was created on former downland located on the north-facing slopes in the 1930's. Today it consists of dead or dying Scots Pines, Beeches and many other species like Ash, Sycamore, and Whitebeam, which have forced their way into the gaps in the plantation. The owner of the plantations above Cat's Whisker is in the process of removing all the 1930's woodland and is hoping it can be restored to chalk downland. The Dorset Wildlife Trust have to decide what course to follow. Transect data shows that the Cat's Whisker Section 3 of the butterfly walk has a declining percentage of butterflies counted on the Reserve. This is probably because the trees on either side of the path are growing taller and the shade is increasing. The two butterflies most frequently found in this section are the Speckled Wood and Ringlet. But transect data shows that even they are drawing a smaller percentage of their total count from Section 3. As far as butterflies are concerned the data shows that this section is diminishing in interest but remember that the committee must not just base its decision on butterflies; the Cat's Whisker wood may be of great value to birds, ferns, fungi or any other order. But at least the walk figures give the management something clear to base their actions on.So butterfly counting is fun, keeps the weight down and helps managers of the Reserves to make informed decisions rather than guesses. In the future it will probably help to unravel the mysteries of the short-term fluctuations in the numbers of so many species and help conservationists to spot which of these are beyond their control and which may be countered by changes in management. If global warming does become a reality the walk data should quickly detect it and help to make an accurate record of whatever fascinating changes occur. The only disadvantage is that future generations will lose the chance to beguile the young with nostalgic stories of those vast clouds of butterflies because the precise data will be on record for all to check!