Supplementing wild populations

Ducks lay large clutches and often re-lay if the first clutch is lost. The eggs of most species are easy to hatch in incubators, under hens or foster ducks, and the survival of ducklings is excellent under captive conditions. In the wild the weather, food shortage and competition take their toll and the brood is reduced from 8–12 at hatching to 2–4 at fledging. It would, therefore, be easy to increase the number of fledged young produced, by taking the first clutch of eggs (allowing the female to re-lay again), hatching and rearing them artificially, and releasing them onto the breeding area or similar habitat. This has been practised for centuries in Britain and intensively for decades in North America, with the aims of:

1. a) increasing the number of ducks available for autumn and winter shooting and

2. b) supplementing wild populations for future breeding seasons.

3. An additional aim of the WAGBI scheme in Britain (249) was

4. c) to encourage a responsible attitude to harvesting and an interest in conservation in every wildfowler.

Mallard originating from game-farm stock are not likely to behave like wild birds in either tameness or flying ability, so eggs taken from wild birds are preferable. If eggs are taken early the duck will re-lay and there will be a minimum loss to the wild birds. In North America young ducks are usually released at 6 weeks of age, two or three weeks before fledging, these doing better than older or younger ducklings (82). Nevertheless, losses of birds liberated in unprotected places are up to 30% between release and fledging (194).

Knowledge of the origins and movements of wildfowl is essential if they are to be effectively managed or conserved. The Wildfowl Inquiry Committee was initially responsible for coordinating and stimulating efforts (591). By 1937 the ringing scheme had been transferred to the management of the BTO and all subsequent rings bore the address of the British Museum (Natural History).

The Wildfowl Trust was making a substantial contribution to the ringing effort soon after its establishment in 1946, and in 1954 responsibility for wildfowl ringing was transferred from the Wildfowl Inquiry Committee to the Trust. Table 1 gives the number of wildfowl ringed by the Trust and in Britain as a whole, to the end of 1981. Apart from the Mute Swan, the subject of a large number of local population studies, the Trust has been responsible for the vast majority of geese and swans ringed. Expeditions to the Arctic breeding grounds of Barnacle and Pink-footed Geese have added considerably to the total ringed by the Wildfowl Trust. The majority of ringed ducks have been marked at the Trust's trapping stations, but a few species have been the subject of special studies elsewhere. For example, most of the Eiders and many of the Shelducks have been marked in connection with population studies on the Ythan Estuary, Aberdeen, and the Goosanders have largely been caught by a ringing group in Northumberland (337).

The majority of marked birds have been ringed in the last two decades, largely as a result of new trapping stations coming into operation and new methods of catching yielding greater numbers of certain species.

Lesser White-fronted Goose Anser erythropus

A smaller, close relative of the Whitefront, this species breeds across northern Europe and Asia from Norway to eastern Siberia. It is an upland breeder and migrates through central Europe to winter around the Black and Caspian Seas and south-western Asia. Stragglers to Britain are almost always seen with European Whitefronts; up to 1982 there had been just over 100 records, well over half of these at the New Grounds on the upper Severn Estuary, where it was first recorded in 1945. Before then there had been only 2 sightings, the first in 1886. The largest number present in any one year was 4 at the New Grounds in 1979-80. Probable hybrids with the Whitefront are sometimes reported.

Snow Goose

Anser caerulescens

A numerous species of North America, the Lesser Snow Goose A. c. caerulescens has a blue and a white phase; the Greater Snow Goose A. c. atlanticus has only the white form. Both races, and both phases of the Lesser Snow, occur almost annually in Scotland and occasionally in England, usually with flocks of other geese. The species is, however, commonly kept in captivity in a fully-winged state and it is impossible nowadays to establish which birds are wild. Those accompanying Whitefronts from west Greenland are more likely to be so; a group of 18 seen in the Netherlands in 1980 contained a single adult ringed in southern Hudson Bay.

History and organisation

The Wildfowl Count network was set up in 1947 by the International Wildfowl Inquiry Committee and a Central Organiser was appointed. The aim was to cover as many waters as possible once in each winter month, September – March. The network was made up of volunteer observers and coverage was inevitably incomplete, but special efforts were made to obtain regular counts from the most important sites. The Wildfowl Trust took responsibility for the counts in 1954 and the Organiser (G.L. Atkinson-Willes) moved to Slimbridge. By this time the number of waters counted had risen to more than 500 and about 700 volunteer counters were involved. By the early 1960s more than 2,000 waters had been covered at some time although the average number of counts received was 5–600 in each month.

An International Wildfowl Count scheme was set up by the International Waterfowl Research Bureau at Slimbridge in the mid 1960s, aiming to cover the whole of the western Palearctic range in January each year, and in some years in November or March. When these counts began, with the first full survey in 1967, there was a major impetus to increase the coverage in Britain even further and Regional Organisers recruited more observers. The usual number of counts made in January (the month with most complete coverage) rose to 1,100–1,300 and in other months to 700–900. By 1982, more than 4,000 waters had been covered at some time since 1960 and in the early 1980s more than 1,100 individual counters were involved.

Having reviewed the considerable progress made in the conservation of wildfowl and their habitats in the 1950s, the First Edition ended on an optimistic note, concluding that science was playing an increasingly important part in the process of conservation. Reviewing the position since then, we are again justifiably pleased with the progress. Two major developments give us particular grounds for optimism. One is the emergence of the International Waterfowl Research Bureau as a major force in international conservation, leading to the establishment of the Ramsar Convention. The commitment of the Nature Conservancy Council and the government to the Convention is illustrated by the fact that the list of sites proposed for designation under Ramsar includes all those wetlands qualifying under the 1% criterion. The other major development in the 1970s was in the contribution made by the voluntary organisations to the conservation of our wetland habitats.

The Wildlife and Countryside Act (1981) increased the number of wildfowl given protection in law and also extended protection to habitats in the case of SSSIs. The NCC has the burden of making this legislation work in practice. There have been setbacks, but we hope that landowners and conservationists can work together to protect our most important sites. An encouraging and extremely important factor is the growth in public interest and involvement in aspects of conservation in recent years.

Our challenge now is to maintain and build on this favourable situation and safeguard our wetlands for the future. Since wildfowlers, voluntary and governmental conservation bodies and many other organisations are working together, we are hopeful that we will succeed.

Aims and criteria

The aims of wildfowl conservation

Wildfowl have long been appreciated by man, as a source of both food and enjoyment, either through sport or sheer appreciation of their beauty, wildness and behaviour. Given the background of pressures and possibilities described in previous chapters, the role of conservation is to ensure a future for wildfowl in a constantly changing environment. Following discussions in the late 1950s between the Nature Conservancy, the Wildfowlers’ Association of Great Britain and Ireland and the Wildfowl Trust, a statement of aims was agreed in 1960. The purpose of wildfowl conservation was stated as (a) to safeguard species from the threat of extinction, and (b) to maintain existing stocks in at least their present strength and in their present distribution.

No species or subspecies was in danger of extinction in Britain in the early 1960s, and since that time changes in numbers have almost invariably been upwards or merely short-term fluctuations as a result of environmental conditions. We must reserve this responsibility as our overriding aim, however, and restate it here.

As we have seen in Part III, the aim of maintaining stocks and distribution has been more than achieved in the last 20 years, indeed several species have increased in number and spread during that time. These increases have been brought about for different reasons. In the case of Dark-bellied Brent and, to a large extent other species of geese, the increases have been a result of a lowering of shooting pressure, helped by favourable breeding seasons, and can be regarded more as a recovery than a real advance.

The data from the National Wildfowl Counts and the International Censuses have been used in many different ways in this book, the aim throughout being to furnish a sound scientific basis for the conservation of both birds and habitat. Their use to examine trends in numbers, to assess British populations and to map wildfowl distribution is described in Part III. Part IV discusses the ways in which counts are used to establish criteria for recognising sites of international importance and for assessing the value of individual areas in the national context.

The survey of wildfowl habitat and distribution which follows is concerned with the wetlands within each district, the populations of wildfowl occurring on them, and the changes which have taken place over the past 20–30 years. Apart from the sections written by the main authors, G.V.T. Matthews wrote “The Warwickshire Avon, middle Severn and Teme Basins”, “East and central England”, “North-west England”, and “Teesdale, Tyneside and the Borders” M. A. Ogilvie wrote “The inner Sol way Firth”, “Inland Dumfries”, “The Stewartry and Wigtown”, “The Clyde Basin” and “South-east Scotland”; M. Smart wrote “The lower Severn Vale”; and G.M. Williams and A. Henderson wrote “North Kent”.

The survey has been divided into nine chapters, corresponding to the principal water basins or “faunal regions”. The continued proliferation of man-made waters, often close to watersheds, has rendered the divisions between the regions less distinct than in the First Edition, but this is still considered the most logical system for a review of wildfowl distribution. The regional boundaries are shown in Fig 60 (p.339), and an enlargement of the appropriate part of this map is presented for each region.

Traditionally, wildfowlers have contributed much to our knowledge of wildfowl numbers, distribution and habits, although early information was not as rigidly quantitative as we might have liked. The early writings and reminiscences of shooters, such as Colonel Hawker (254), John Millais (344) and others (285), often provide the only accounts of the abundance of wildfowl against which present numbers and distribution can be judged. Later, wildfowlers began to contribute scientific data on habits and foods which were valuable in the understanding of the requirements of the birds (107, 110). When biologists began studying ecological aspects of wildfowl in detail in the late 1950s and 1960s, wildfowlers became part of the collecting mechanism; information or samples supplied by them still provide a valuable source of scientific information.

Duck production surveys

Whereas geese and swans can be aged by observation in the field and valuable information on production and population dynamics so gained, ducks are only reliably aged in the hand. We have seen that the age ratios of caught ducks give unreliable estimates of the proportion of young in the population (p.18) and considerable efforts have been expended in attempting to collect such information from shot birds. A preliminary key to the sex and age identification of wildfowl from wings only was published in 1964 by the United States Fish and Wildlife Service (117) and this provided a stimulus to a pilot study in Britain in 1965 (246). Wildfowlers were asked to send in a single wing from ducks they shot and these were examined by experts who classified them by species, sex and age (adult or first winter).

Two decades have passed since the publication, in 1963, of the First Edition of Wildfowl in Great Britain (edited by G.L. Atkinson-Willes, published by HMSO) – the first comprehensive survey into wildfowl habitats, stocks and prospects in Britain. Because of sparsity and irregularity of cover it proved impossible to include Ireland, either in the previous volume or in this work, but a separate study was carried out there recently (279).

The aim of the original survey was to provide a basis for conservation planning following the 1954 Protection of Birds Act and the formation by the then Nature Conservancy of the Wildfowl Conservation Committee to advise on wildfowl conservation and exploitation. Prior to this there had been much debate on the status of wildfowl and the effects of shooting, with conflicts arising largely from the lack of objectively gathered information on numbers and distribution. Wildfowl in Great Britain summarised the information collected during 14 years of Wildfowl Counts and provided a basis for future planning.

The volume more than adequately fulfilled its objectives and it continued until recently to provide basic data for cases of both national and local conservation. The last 20 years have, however, seen major changes not only in the habitat and conservation of wildfowl but also, partly as a result of this, in the status of most wildfowl species wintering in Britain. Following numerous requests from individuals and organisations for a new review the Nature Conservancy Council (NCC) and the Wildfowl Trust decided in 1979 that a complete reassessment should be undertaken.

As one who, in his time, has been a wildfowl counter, both in Britain for the Wildfowl Trust and abroad for the International Waterfowl Research Bureau, it is a particular pleasure to welcome the completion of this Domesday Book of the wildfowl and their wetland habitats. Since its predecessor was published in 1963, the range and bulk of data have greatly increased, thanks to the efforts of several thousand dedicated volunteer workers. The Wildfowl Trust, supported by the Nature Conservancy Council, has played the central role in collecting and analysing the data, but their sister organisations, the British Trust for Ornithology and the Royal Society for the Protection of Birds, have been more than supportive, as have been the Naturalists’ Trusts and Ornithological Societies throughout the country. Indeed this is a very British achievement, basically one of free enterprise but underpinned by a, relatively modest, funding from Government sources.

The vulnerability of wetlands to modern technological developments was recognised by the drawing up in 1971 at Ramsar, in Iran, of the Convention on Wetlands of International Importance Especially as Waterfowl Habitat. With 38 countries now adhering to the convention, and more than 300 wetlands covering some 19 million hectares afforded special protection, the international effort has clearly had considerable success. In the United Kingdom 19 wetlands of international importance have been designated for the Ramsar List and our aim is to extend that status to cover the 132 which satisfy the agreed criteria. The data presented in this book are of crucial importance in this task.