SUFFOLK NATURALISTS' SOCIETY CONFERENCE, 29TH OCTOBER 1994 BREEDING BIRDS OF EAST ANGLIA The Annual Conference was held on Saturday 29th October 1994, at Ipswich School Conference Centre. The conference was sponsored by Anglian Water, together with the British Trust for Ornithology, English Nature, Forest Enterprise, Ipswich Borough Council and Suffolk Wildlife Trust. A synopsis of the papers presented at the conference is given below.
DIGGING FOR BITTERNS - RE-SHAPING MINSMERE'S SCRAPE Geoff Welch As a British breeding bird, the Bittern has had a very chequered history. In the 17th century its range extended throughout England, Wales and southern Scotland and at this time shooting parties in the Fens would bag 20-30 birds in a morning and roast Bittern was the Fenman's traditional Sunday lunch! However, persecution and habitat loss through drainage reduced numbers and by the mid-1800s Bitterns were restricted to the Norfolk Broads. The last nest was found in 1868 and the last young bird killed in 1886. Birds continued to be recorded as passage or winter visitors but breeding was not proved again until 1911, at Hickling Broad. Thanks to enthusiastic protection, numbers began to increase, to reach a peak of around 70 pairs by the late 1960s, but since then there has been a steady decline to just 16 booming males in 1994. Research The RSPB has been aware of, and concerned by, this decline for some time, and in the early 1980s it carried out a great deal of work on its reedbed reserves, opening up ditch systems to provide more feeding edge. However, it was not until 1988 that a detailed investigation into the species' ecology and habitat requirements was started. One of the greatest problems proved to be how to study a bird which is hardly ever seen! This was tackled in two ways — radio tracking and 'voice fingerprinting'. By fitting small radio transmitters to the legs of three birds at the RSPB's Leighton Moss reserve in Lancashire, it was shown that male Bitterns move around a reedbed far more than was originally thought, and may have several booming sites within their territory. The latter fact is very significant, as in the past Bitterns were censused by mapping boom sites — but i f males are highly mobile there is a real risk of over-estimating the number of males present. Radio tracking also revealed that rather than feeding along ditch edges, Bitterns frequently feed a few metres in from the ditch, in the reedbed. But this is only possible when water levels in the ditches and reedbed are high enough for fish, eels and frogs to swim out of the ditches and through the reeds where the Bitterns can catch them. Basically, Bitterns need really wet reedbeds! Linking in with the radio tracking, the RSPB, working closely with Nottingham University, has found that the boom of each male is individually recognisable i f good quality tape recordings are used to produce a visual representation of the boom, known as a sonogram. Given recordings of all the booming birds, an accurate assessment of the number of males can be made and an annual census of booming males by this technique now forms a major part of the ongoing study of the species. What is not yet clear is whether all males keep the same boom pattern from year to 7
year. I f they do, this will provide valuable information on site fidelity and any movements between breeding sites. Linked to the direct study of the species, the RSPB has also been examining various environmental and physical characteristics of reedbeds currently and historically occupied by Bitterns. Characteristics studied have included prey availability (by electro-fishing), relative areas of scrub, reed and open water on each site, water depth, length of ditch/pool edge and an assessment of reed quality and stem density. Habitat Management Based on the findings of the research, size of reedbed and site wetness come out as very important and much of the current work taking place on reserves is aimed at these. In Suffolk, the majority of the coastal reedbeds, especially Bittern at Minsmere and Walberswick, were formed during the Second World War when areas of grazing marsh were flooded as an anti-invasion measure. At Minsmere most management in the 1970s and 1980s focused on scrub removal, but the problem of accumulating leaf litter, which was making parts of the reedbed too dry for Bitterns, was not tackled until 1991. The problem has been tackled in two ways. The first has been to set up an experimental seven year rotational cutting programme over a quarter of the main reedbed at Minsmere. Each winter several small blocks of reed, scattered throughout the reedbed and measuring up to 0.5 hectare, are cut. The reed is cut using a brushcutter or Iseki mower, and is then raked up and burnt. Each area is then re-raked to remove as much of the leaf litter as possible, and the rakings are piled around the edges of each block to provide invertebrate habitat. A narrow fringe of reed around each block is left uncut, and this provides some screening whilst also linking the cut area to the surrounding reedbed. The process in effect creates a series of small, shallow pools within the reedbed which are gradually encroached by reed. They appear to be providing ideal feeding areas for Bitterns as reserve staff and visitors have observed birds using the managed blocks. However, in some areas litter is so dense that management by cutting is not sufficient — and then the second, more drastic method is employed. At both North Warren and Minsmere contractors are being used to dig out up to 25 hectares of dry reedbed at each site over a period of five years. Ground levels are being lowered by up to 60 cm and the resulting spoil is being used to create new banks to improve water control. As with the cutting, reed will gradually recolonise each area, but 8
where the reedbed was dry and the reed old, thin and stunted, growth will now be young, vigorous and tall, with the ground below very wet providing prime habitat for one of this country's rarest breeding birds. With one third of the British Bittern population breeding in Suffolk, hopefully these efforts will not prove to be too late. Geoff Welch, RSPB, Minsmere, Westleton, Saxmundham IP 17 3BY M A N A G E M E N T AND B I R D S I N W O O D L A N D N A T U R E R E S E R V E S : FROM COPPICE T O NATURAL FOREST. Dr Robert J Fuller Woodland supports more species of breeding birds than any other vegetation type in Britain, yet surprisingly few woodland species are nationally rare (Fuller 1995). Perhaps it is partly for this reason that woodland has become increasingly regarded as a relatively low priority habitat for bird conservation. Nonetheless, woodland birds have great appeal and managers of woodland nature reserves frequently aim to treat their woods in ways that enhance bird populations. There can, however, be few woodland nature reserves in lowland England that are managed purely for birds. The aims of conservation management within the majority of woodland reserves are to encourage a diversity of wildlife of which birds are a part. Substantial numbers of ancient woods have been acquired as nature reserves over the past 20 years. The demand for information about how best to manage these sites has grown accordingly because it is widely assumed that management is necessary to maintain an interesting and diverse wildlife. Habitat management will always be a cornerstone of nature conservation within woodland but I suggest that there is room for a more critical approach. Too seldom are the reasons for intervention clearly defined and it is not always appreciated that there are interesting and valid alternatives to traditional management systems. Birds provide several useful examples in developing these ideas. Coppicing: advantages and problems Coppicing is the most widely practised form of conservation management in woods. One justification is that the patchiness of a coppiced wood benefits a large number of species. In Bradfield Woods, for example, a range of bird species is sustained by the various growth stages (Fuller & Henderson 1992). Recently cut coppice is colonised by birds such as Whitethroat aftd Dunnock. As the coppice thickens these give way to Willow Warblers, Garden Warblers, Blackcaps and Nightingales. From an ornithological viewpoint the most striking feature of well managed coppice is the extremely high breeding densities of these summer visitors. Soon after canopyclosure (typically at 6-8 years of growth) these migrant species disappear, to be replaced by Robins and several species of tits. Provided that new areas of coppice are cut regularly, coppicing can sustain habitats for a large number of birds and other species within a wood. For coppicing to succeed, however, the density of large standard trees must not be too high, otherwise the shade will suppress the coppice regrowth to the detriment of breeding Nightingales and warblers. Even where coppicing is carried out correctly there are increasing difficulties of achieving good regeneration. Numbers of deer especially Roe Deer and Muntjac, are rising in lowland England and their impact on coppice can be devastating. At Bradfield Woods, for example, Roe Deer became a serious problem in the late 1980s when it was realised that without action the future of coppicing at this historic site was in jeopardy. A two-fold approach was taken by the Suffolk Wildlife Trust which 9
involved reduction of the deer population, with the aid of a professional stalker, and the erection of tall, dense brushwood fences around newly cut patches of coppice. This action has successfully reduced damage to the coppiced woods. The increased pressure from deer in Bradfield Woods in the late 1980s may have contributed to the decline of Nightingales from an estimated 17 territories in 1987 to less than ten in 1994. In those areas not protected by robust brushwood fences, heavy deer browsing has inhibited coppice regrowth such that a very open canopy and dense field layer have persisted many years after cutting. This vegetation structure is poor Nightingale habitat; the birds need a dense shrub layer or thicket, combined with patches of bare ground for feeding. It will be interesting to see whether the Nightingale in Bradfield Woods recovers in future years now that all young coppice is being effectively protected from severe browsing. The case for coppicing is especially strong where there has been a recent or continuous history of coppicing, as at Bradfield Woods, or where it has only recently ceased (Fuller & Peterken 1995). Such woods are most likely to have retained those early successional plant and invertebrate species that depend on continuity of management. Where there has been a long break in coppicing it is less probable that a rich community of coppice plants and animals can be restored though the more mobile species, including several warblers, may rapidly colonise. Coppicing is labour intensive and, in addition to the problems of deer, there are substantial difficulties in marketing the products of coppice. Striking a balance in woodland management High forest — woodland managed on longer rotations with the aim of producing timber trees — supports bird communities which are broadly complementary to those of coppice. Notwithstanding the fact that bird communities in individual woods vary enormously in response to many different factors (Fuller 1995), stands dominated by mature broadleaves will hold larger populations of Nuthatches, Treecreepers, tits and woodpeckers than will coppiced stands. Rarely, however, does English high forest support the high densities of summer visitors often found in coppice. It is entirely appropriate that some woodland reserves should be managed as high forest and that others should not be managed at all. Natural temperate woodland is characterised by the presence of massive trees, large amounts of dead wood and treefall gaps of various sizes. Exceedingly few English woods have a structure that could be regarded as remotely natural; even dead wood is scarce in many woods. Nature reserves offer exciting long-term opportunities for allowing more natural structures to develop within English woodland (Fuller & Peterken 1995). Derelict coppice within reserves could form the basis for an expanded area of high forest and creation of a modest number of natural woods. Coppice, scrub, wood-pasture, high forest and natural woodland all have a place in English nature reserves. Each supports complementary communities of birds and other wildlife. Given the large area of protected woodland in lowland England there would seem to be scope for developing an integrated approach to woodlands whereby different woods offered substantial examples of different management systems and woodland habitats. A diversity of woodland treatments is desirable but, in general, this is better achieved through treating different woods in different ways, rather than trying to achieve too much within individual woods. The BTO's work on woodland birds is partly funded by the Joint Nature Conservation Committee (on behalf of English Nature, Scottish Natural Heritage, The Countryside Council for Wales and DoE Northern Ireland). • 10
References Fuller, R J (1995) Birdlife of Woodland and Forest. Cambridge University Press, Cambridge Fuller, R J & Henderson, A C B (1992). Distribution of breeding songbirds in Bradfield Woods, Suffolk, in relation to vegetation and coppice management. Bird Study 39: 73-88. Fuller, R J & Peterken, G F (1995). Woodland and scrub. In Habitat Management for Conservation. Editors: W J Sutherland & D A Hill. Cambridge University Press, Cambridge.
Dr Robert J Fuller, British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU
G O L D E N ORIOLES IN T H E FENS Paul Mason and Martin Raines Golden Orioles started to breed in appreciable numbers in East Anglia in 1967 when two pairs were found in the Bryant and May poplar plantation near Lakenheath in Suffolk. The matchmaking company had embarked on a homegrown wood project which would eventually encompass some 700 acres. The number of breeding birds reached around 14 pairs by 1981, by which time the company changed its policy and sold the land. The new owners embarked on a programme to return the business to agriculture and tree felling proceeded until 1989-90 when an agreement between the owners and the RSPB resulted in 100 acres being left in hybrid poplar production, on a rotational basis. We hope that this will result in two or three pairs of Golden Orioles having a reasonably safe future there. During the tree felling, which was spread over several years, concerned individuals, who had been watching the birds and the subsequent disappearance of the habitat with foreboding, came together and formed a 'Golden Oriole Group'. This body was to study what happened to the displaced birds. Would they disappear to where they originated — thought by now (1994) to be the Low Countries, or would they disperse into smaller poplar plantations in other parts of Suffolk, Norfolk and Cambridgeshire? Thankfully, it was found to be the latter which occurred. It is not known exactly when the birds moved into areas of SW Norfolk, but a breeding pair reached Cambridgeshire in 1982, and the numbers gradually increased until nine sites were identified, though these breeding sites were not all used every year. A large number of breeding sites was* found in Norfolk, and two new ones in West Suffolk. Having located a number of sites and some potential ones, some 30-35 in all, the Group, together with the RSPB, decided to investigate the birds' habitat requirements in more detail. There are several different cultivars of hybrid poplars and it was found that whilst all cultivars are used for foraging, only a few are used for nesting by the Golden Orioles, mainly the early and large leaved cultivars. With the help of a grant from the Environmental Research Foundation, researchers from the University of Oxford assessed invertebrate populations on the various cultivars. The height and orientation of nests were recorded. Nest watches were established to find when the parents were feeding their young and various feeding rotas were noted. Areas of foraging and the distances travelled in doing so were appraised and the minimum number of trees needed was estimated. Behaviour is being studied, partly through photography undertaken by Malcolm Raines and Chris Knights. A ringing programme commenced in 1987 and 50 pulli and one adult have been ringed. It is impossible to ring all pulli as many nests are inaccessible, being as high as 25m and often on flimsy branches. Two recoveries and two controls have resulted; a high rate of return. Evidence is being obtained of the age of breeding females, site fidelity and direction of migration, together with the possible origin of the population. 11
Breeding success is, of course, recorded, showing the number of breeding pairs peaking in two years, (i) 1987, when several were known to fail subsequently because of incessant rain in June, and (ii) 1993, which is believed to have produced record numbers of young. Ironically, the worst season seems to have been 1994, when cold wet weather and violent thunderstorms together caused pairs to desert their nests. In 1994, a grant was received from English Nature to survey Golden Orioles on a national basis, including mapping poplar plantations in the core Fenland Basin breeding area. Volunteers throughout England agreed to keep a watchful eye. Unfortunately, owing to the inclement summer weather, poor results were obtained. The decision has been taken to extend the survey into 1995. As for the future, there is good reason to be optimistic. Since the departure of Bryant and May and its decision to use imported wood, the market for poplar has declined. Present uses are mainly for pallet making, spills for schools and for protective packaging for transporting high-quality specialised bricks. Fresh uses for poplar wood are gradually being found, such as the manufacture of specialised musical instruments and some furniture. New cultivars of hybrid poplar have been produced in Belgium. These are quicker growing, making cultivation more commercially viable, and they have been found to be suitable for more uses, including timber for roof trusses and furniture veneers. As a result of this work higher quality premiums for such wood can be expected. The Golden Oriole Group is investigating which of these cultivars are also good for Golden Orioles. Two members visited Belgium in 1992, and another visit is planned. So far it seems that the birds are using plantations of the new cultivars, so the future is promising. Several landowners have planted new shelter belts of poplars to prevent soil erosion, and in Cambridgeshire a new wood of nine acres is to be planted as an amenity for local people. This is a joint venture between Haddenham Conservation Society, the Woodland Trust and the Cambridgeshire Woodland Fund. The project was awarded ÂŁ6,000 by Anglian Water under their 'Caring for the Environment Award Scheme 1994'. Planting of three varieties of poplar is planned, with a screen of native fenland trees and suitable understorey. We hope that Golden Orioles will use it in 8-10 years' time. It will then be the only Golden Oriole site legally open to the general public. In other parts of the country the Golden Oriole only breeds sporadically. In the southern counties poplars are largely scorned in favour of mature oak cover with a chestnut coppice understorey. This fact, together with ringing recovery evidence, leads us to believe such birds are from a different population, probably based in Iberia or Western France. Some 150 birds are recorded in most years along our coastlines, but most seem to filter inland or disappear back to the Continental mainland and are therefore regarded as vagrants or migrants. Breeding has occurred, however, in places as far apart as Kent, Somerset, Fife and Yorkshire. The Scottish and Yorkshire birds which bred in poplars might be of Low Countries' origin. Further research will be carried out and the possibility of investigating song patterns is being considered. Regular reports are being sent to English Nature, the Rare Breeding Birds Panel and the RSPB. The Golden Oriole Group is prepared to give other organisations similar, and perhaps more detailed exhibitions than was possible at the Ipswich Conference in 1994. Please contact Malcolm Raines on 01366 377233 or at Mantons Farm, Ten Mile Bank, Downham Market, Norfolk, PE38 0EW. A small charge will be made and the money used to help with the Golden Oriole Group's research costs. Paul Mason, Highfield House, Hillrow, Haddenham, Ely, Cambridgeshire. CB6 3TJ 12
BREEDING BIRDS IN FARMLAND Dr Peter Lack Farmland occupies about 70% of the land surface of Britain and is an important habitat for many birds and other wildlife. It is very varied and, apart from the fields, contains a high diversity of small pieces of many other habitat types such as hedges, woodland, ponds and farm buildings. Management is often heavy, especially on the fields and their immediate surrounds, and the practices adopted can have major effects on the birds and other wildlife, although in some cases there are straightforward and not too costly ways of alleviating some of these. The following does not attempt to cover all the possible aspects of how farming affects the birds which live in the habitat but picks out a few of those topics which we know most about. The populations of many birds in farmland have been declining steadily, especially over the last 20 years or so (Marchant et al 1990), and more so than in any other major habitat type (Gibbons et al 1993). However not all groups are affected to the same degree and seed-eating species such as some finches and buntings seem to be particularly badly hit. Furthermore some recent work has shown that the declines of seed-eaters have been more pronounced in areas where arable farming is predominant compared with areas of predominantly grass and livestock farming (Marchant & Gregory in press). Some of the declines can be related to modern farming practices such as the increased use of pesticides. Despite the British Trust for Ornithology and others working on birds in farmland for some years, there is still much to learn about exactly what each species needs from farmland, and about how the different species actually use the various habitats of which farmland is composed. The remainder of this article summarises some of our current knowledge on crop preferences and on hedges and their management. The preferences of some birds for different field types is quite well known, for example wader species such as Snipe Gallinago gallinago and Redshank Tringa totanus are almost restricted to wet or damp permanent grassland when nesting inland and, as a consequence, their numbers have often declined following drainage (Gibbons et al 1993). Only a few species nest in arable fields and most show some preferences between crop types. Most prefer crops which are sown in the spring to those sown in the autumn, for example Skylark Alauda arvensis and Lapwing Vanellus vanellus, probably because the vegetation is much lower at the stage — when the birds are looking to nest. The latter species has been the subject of several detailed studies. The BTO survey of England and Wales in 1987 showed a very strong preference for spring sown arable fields for nests, but Lapwings also additionally prefer those fields adjacent to areas of grass probably because this latter is the preferred field type for their chicks (Shrubb & Lack 1991). Reed Bunting 13
Birds nesting in hedgerows, by contrast, show a rather different pattern of preferences. There are more bird territories adjacent to oilseed rape fields than other crops and Dunnock Prunella modularis, Blackbird Turdus merula and Reed Bunting Emberiza schoeniclus show a particularly strong preference (Lack 1992). Indeed the Dunnock and Reed Bunting have been found nesting actually within rape fields. Several species nesting in hedges do forage in the fields and the reason for the preference for rape fields may be that the ground under that crop is much more open than under cereals, thus allowing more feeding opportunities. This suggestion of access being a critical factor is strengthened by the observation that birds are often seen to use the 'tramlines' left by passes of the tractors as a means of gaining access to all types of crop. Hedges are arguably the most important habitat feature for birds in farmland. However it is essential that the hedges are managed. Unmanaged hedges often quickly become less suitable as they tend to become thin near the base. The 'best' type of hedge is large, tall and wide, contains a variety of shrub species and has a ditch alongside. It appears that the presence of thick vegetation near the base is especially important for many species, but one of the easiest ways to increase the numbers of birds is to have some trees, although it is not clear exactly what many of the birds use the trees for. Even small trees can have a beneficial effect, but not all bird species like them. Blue Tits Parus caeruleus and Blackcaps Sylvia atricapilla for example are much commoner i f trees are present, but Dunnocks and Yellowhammers Emberiza citrinella seem to occur equally commonly whether there are trees in the hedge or not. Management of hedges can be done in several ways. The ideal is not to do any cutting until after any berries have been eaten in the autumn and not too frequently. Regular trimming every year or two with a mechanical flail is the most common
Blue Tit 14
method, but other methods include laying or a severe cut, even what amounts to coppicing, every ten years or so, perhaps with minor trims between. The latter method clearly will make a hedge less attractive in the short term but in the longer term can be beneficial in ensuring a thick base is re-established. Two recent papers (Green et al 1994, Parish et al 1994) spell out much of this in more detail. Overall in farmland it is clear that each bird species has particular requirements of its habitat, and although there are some practices which will benefit a range of species, any management is likely to result in both gains and losses. It is essential to decide on objectives and set out the priorities before any management is done. It is also clear that, until recently, farmland has been relatively neglected as a habitat by conservationists. Changes in agricultural practices can occur very rapidly, often as a result of political decisions not agricultural ones, and can affect very large numbers of birds. It is vital therefore that birds and other wildlife continue to be monitored there, and that we find out more about their food and other requirements. References Gibbons, D W, Reid J B & Chapman R 1993. The New Atlas of Breeding Birds in Britain and Ireland: 1988-1991. T & A D Poyser, London Green, R E, Osborne, P E & Sears, E J 1994. The distribution of passerine birds in hedgerows during the breeding season in relation to characteristics of the hedgerow and adjacent farmland. Journal of Applied Ecology 31: 677-692. Lack, P C 1992 Birds on Lowland Farms. HMSO, London. Marchant, J H, Hudson, R, Carter S P & Whittington, P S 1990. Population Trends in British Birds. British Trust for Ornithology, Tring. Marchant, J H & Gregory, R D (in press) Recent population changes among seed-eating passerines in the United Kingdom. Proc. 12th Int. Conf. of IBCC and EOAC, The Netherlands. Parish, T, Lakhani, K H & Sparks, T H 1994. Modelling the relationship between bird population variables and hedgerow and other field margin attributes. I . Species richness of winter, summer and breeding birds. Journal of Applied Ecology 31: 764-775. Shrubb, M & Lack, P C 1991. The numbers and distribution of Lapwings V. vanellus nesting in England and Wales in 1987. Bird Study 38: 20-37.
Dr Peter Lack, British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU
BIRDS O F P R E Y IN S U F F O L K Derek Moore Marsh Harrier Historically, the Marsh Harrier probably did not breed in East Anglia this century until during the Second World War. It is reasonable to speculate that this species must have been numerous centuries ago when the fens were flooded and considerable suitable habitat existed. Ticehurst, however, in 1932 (A History of the Birds of Suffolk) stated that he could find no evidence of Marsh Harriers breeding in Suffolk for the past 100 years. Since the 1940s the situation has changed. Numbers were reasonably steady at about a dozen nests until 1971 when only one pair was present in the country at Minsmere. The reason for the sudden decline is attributed to organochlorine pesticides rather than losses of habitat. Indeed in Suffolk, reedbeds increased after the Second World War because of deliberate flooding. The withdrawal of harmful pesticides saw a steady increase in Marsh Harriers and this may have coincided with a population explosion in the Netherlands during 15
LU
polder creation. The new habit of females wintering in Britain is perhaps also significant, as well as the increased polygamous behaviour of males. The recent increases mean that probably at least 100 nests occur each year in south-eastern England. Habitat preference is reedbeds with good areas of feeding nearby, i.e. grazing marshes or estuary. Minsmere has had Marsh Harriers breeding in every season for the last 40 years. In Norfolk arable crops are increasingly used, but no records of such habitat use have yet been submitted for Suffolk.
Goshawk For such a large bird of prey the Goshawk is incredibly elusive and, as such, may be under-recorded. Mythical stories from the west of Suffolk reached the birding hard core sitting comfortably on the coast back in the early 1970s that these splendid birds might be nesting. This proved to be the truth and this population is still strong today and slowly increasing. Additionally what were at first thought to be winter visitors from the Continent were proved to be breeding on the Suffolk coast. The large Forestry Commission plantations are Marsh Harrier splendid habitat for this species. The origins of this expanding British population are interesting. There is no doubt that many birds were released by falconers presumably to provide a regular supply of wild-bred birds. Thus individuals showing characteristics of different races are often found in small areas. One assumes that some birds from the Continent will have joined the East Anglian population. The situation in Suffolk is difficult to assess accurately. Apart from the now wellknown Breckland birds there is firm evidence of birds nesting on the coast, and strong suspicions of isolated pairs at various sites in the south of the County. Nesting Goshawks are very shy. After early display high above the territory they retreat to thick cover. Sparrowhawk This is another species which declined sharply during the period of organochlorine pesticides. This was particularly marked in lowland Britain where arable farming was concentrated. The Suffolk population reduced to the point where only a handful of pairs still nested. The best chance of seeing this species during the 1960s and 1970s was in winter when Continental immigrants graced the Suffolk countryside. With the abandonment of the harmful chemicals and the sanctuary of forestry pines the Sparrowhawk began a rapid comeback. Today it is possible to see this species daily as you journey around the County. Nesting not only takes place within 16
Sparrowhawk the countryside but also in large urban areas. This species is recorded more than almost any other raptor now. With a recent decline in small passerines, many claims have arisen that the Sparrowhawk is the main culprit. In fact most of the preferred prey species are holding steady or increasing while the decline of some species is much more likely to have been caused by modern intensive agriculture. If you are a cynic like me you will not be surprised that most of the antagonists have a vested interest in shooting game birds. They would dearly love to see a reduction in the population of this species. Kestrel This species is generally assumed to be the most numerous raptor in the County. Indeed, this may be the case, but the Sparrowhawk may be catching up. Recent evidence suggests a small increase in the population of south-east England, but this may not be the case in Suffolk. Current farming practice reduces the habitat for small mammals and a shortage of voles would spell disaster for the Kestrel. The Kestrel is adapted to life in a variety of habitats, including very urban areas where its diet may feature more small birds. It nests in old buildings and purposebuilt nest boxes, as well as more natural sites such as a hole in a tree, or sometimes the old nest of a crow. Hobby There has been a rapid and recent increase of this species throughout Britain, including Suffolk. Pairs of this dashing falcon have been recorded nesting in Suffolk over a number of years and, indeed, may often have been overlooked as a breeding 17
bird. Juveniles seen on the Suffolk coast in August were often in the past considered to be of Continental origin but were probably local. This species is incredibly secretive once incubation begins. I have searched territories thoroughly and never found the birds until the young have hatched. Hobbies do nest in other habitats besides heathland. One pair regularly breeds in south-central Suffolk in an area of arable and ancient woodland on clay soils. Other territories are in river valleys and by coastal lagoons. Old nests of crows are normally utilised. Studies at one heathland site have seen the birds use trees within 800 metres of each other for six successive seasons. They have produced three fledged young in all but two seasons, with one and two in the lean years. Since the October 1987 hurricane the heathland sites are more open and may be more acceptable to this species. There is no doubt in my mind that a co-ordinated search in early August when the fledged young are noisily present would reveal a significant population, maybe as many as 25 pairs. What of the Future? Montagu's Harrier This species bred successfully in Suffolk in 1967 and maybe again in 1981. The recent colonisation of part of Norfolk and welcome success of nine pairs in 1994 offers optimism that this graceful species might return to Suffolk. It has nested both at heathland and reedbed sites in Suffolk. Ironically, the great success of Marsh Harriers in the latter habitat might make it difficult for the smaller Montagu's. Buzzard We normally associate the Buzzard with rolling wooded country of the west and north. In the Netherlands and Belgium, Buzzards nest in habitat similar to that in East Anglia, yet this species has been unable to get established here, although it is possible that Buzzards have bred undetected in recent years. I cannot help thinking that i f those with game interests took a more positive attitude then this bird could flourish here. Honey Buzzard Rumours are rife that this species has nested recently in Suffolk. It may be true and, given that this species has bred regularly in small numbers in Norfolk in the last decade or so, there is always the possibility. Indeed, there are ancient records which suggest that this species has bred in the past. Although one of the commonest raptors in the World this species has a small but patchy distribution in Britain. This bird cannot tolerate disturbance when nesting and it is believed that some nests are unreported. Honey Buzzards may be increasing. Keep looking! And now for two flippant suggestions . . . Osprey The great increase in Ospreys nesting in Scotland in recent years means that many more pass through southern Britain on migration. In some areas birds have lingered throughout the summer, notably two birds together at Lackford recently. There has been much success in the USA and Germany from erecting artificial nest sites. Indeed many of the pairs now breeding in Scotland are using artificial sites. Should we have a go and put up some artificial nest sites in the hope that one day a pair might stay? 18
Peregrine This species last bred in Suffolk in the tower of Corton Church in the early nineteenth century. Severely hit in the pesticide era, this species has now recovered dramatically. Peregrines are once again annual in Suffolk on passage and in winter, and recently up to two have used the Orwell Bridge as a roosting and plucking site. A carefully placed nest box might do the trick! Continual persecution Despite strict and total protection under the law our birds of prey are still persecuted in this country. They still suffer from the attentions of egg collectors and falconers. Sadly, some shooting estates still ignore the current legislation and destroy these beautiful birds. The success of many of the raptor species in itself leads some to cry for their control. The Sparrowhawk for example. Recently I heard a Suffolk farmer renowned for his good conservation record suggest that there were now too many Marsh Harriers for their own good. I was horrified to see a car sticker in Wales recently which bore the slogan "Half a million songbirds killed by hawks each year — bring back the death penalty". Some serious but misguided people have suggested to me that we should organise a cull of Sparrowhawks. What messages would we send to the rest of the European Community i f we did? Some of us have been fighting hard to persuade French, Italians, Maltese and Cypriots to stop shooting birds of prey on migration. What would they think of us? Derek Moore, Suffolk Wildlife Trust, Brooke House, The Green, Ashbocking, near Ipswich, Suffolk IP6 9JY
THE BTO ATLAS — R E C E N T TRENDS Dr David Gibbons David Gibbons' presentation was based on previously published material available as follows:Gibbons, D W (1991) The New Atlas of Breeding Birds in Britain and Ireland — An overview. SittaS: 11-18. Gibbons, D W (1993) The New Atlas of Breeding Birds — An overview of Methods and Results. British Wildlife 4: 360-366. Gibbons, D W, Reid, J B & Chapman, R A (1993) The New Atlas of Breeding Birds in Britain and Ireland: 1988-1991. T & A D Poyser.
Dr David Gibbons, British Trust for Ornithology, The Nunnery, Thetford, Norfolk. IP24 2PU
T H E STONE C U R L E W IN E A S T ANGLIA Dr Rhys Green Rhys Green's presentation was based on previously published material available as follows:Green, R E & Bowden, C G R (1986) Field characters for ageing and sexing Stone Curlews. British Birds 79: 419-422. Green, R E (1988) Stone Curlew conservation. RSPB Conservation Review 2: 30-33 Green, R E & Tyler, G A (1989) Determination of the diet of the Stone Curlew Burhinus oedicnemus by faecal analysis. Journal of Zoology, London. 217: 311-320. 19
Green, R E (1993) Stone Curlew. In D W Gibbons, J B Reid & R A Chapman, The New Atlas of Breeding Birds in Britain and Ireland: 1988-1991. T & A D Poyser, London. Green, R E & Griffiths, C H (1994) Use of preferred nesting habitat by Stone Curlews Burhinus oedicnemus in relation to vegetation structure. Journal of Zoology, London 233: 457-471. Green, R E (1995). Monitoring of Stone Curlew numbers and breeding success. In Carter, S P (Ed) Britain's birds in 1991-1992: the conservation and monitoring review. BTO & JNCC, Thetford. Green, R E & Taylor, C R (in press) Changes in Stone Curlew distribution and abundance and vegetation height on chalk grassland at Porton Down, Wiltshire. Bird Study.
Dr Rhys Green, RSPB, The Lodge, Sandy, Bedfordshire. SGI 9 2DL
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