ISSN 00389144 Scottish Birds the Journal of the Scottish Ornithologists' Club
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VoI.18 No.1 ISSN 00389144 Scottish Birds The Journal of the Scottish Ornithologists' Club Editor: N. Picozzi Assisted by: M.P. Harris, M.A. Ogilvie and S. Wanless Business Editor: The Secretary, S.O.e., 21 Regent Terrace, Edinburgh EH7 5BT. Scottish Birds, the official journal of the Scottish Ornithologists' Club, publishes original material relating to ornithology in Scotland. Papers and notes should be sent to The Editor, Scottish Birds, 21 Regent Terrace, Edinburgh EH7 5BT. One issue of Scottish Birds is published each year, in December. Scottish Birds is issued free to members of the Scottish Ornithologists' Club, who also receive the quarterly newsletter Scottish Bird News and the annual Scottish Bird Report. These are available to non-members at a subscription rate (1990) of £30. The Scottish Ornithologists' Club was formed in 1936 to encourage all aspects of ornithology in Scotland. It has local branches which meet in Aberdeen, Ayr, the Borders, Dumfries, Dundee, Edinburgh, Glasgow, Inverness, New Galloway, Orkney, St Andrews, Stirling, Stranraer and Thurso, each with its own programme of field meetings and winter lectures. The Waters ton Library at the Club's headquarters at 21 Regent Terrace, Edinburgh EH7 5BT is one of the most comprehensive ornithological libraries in Scotland, and is available for reference during office hours (Monday to Friday, 9am to 5pm). A comprehensive stock of Scottish local bird reports is held at the headquarters and may be purchased by mail order. SOC annual membership subscription rates Adult ... .......... ................................. .... ........ .................. ....................... £12 .00 Junior (under 18, or student under 25) ........................ .. .. .................. ........... £5.00 Family (husband & wife, & children under 18) ...................... ................ ....... £18.00 Life Individual ............ ......... .. £240.00 Family ...... ... .. .. ...... .. ............. £360.00 Pensioner Individual .. .. .. ............. £7.00 Family ............................ ........ £10.00 Published by the Scottish Ornithologists' Club, 21 Regent Terrace, Edinburgh EH7 5BT. Printed by Alexander Ritchie & Son Ltd., 163 Bonnington Road, Edinburgh EH6 5RE. Scottish Birds (1990) 16: 1-10 1 East Greenland Barnacle Geese in Scotland, spring 1988 A.D. FOX, M.A. OGILVIE, N. EASTERBEE AND E.M. BIGNAL The East Greenland population of Barnacle Geese, which winters in northern and western Scotland and western Ireland, was censused by combined ground counts and aerial survey in late March 1988. The Scottish component of the population had increased since the last census, in 1983, from 20,820 to 26,950. This 29% increase had taken place solely at the main haunt, Islay (15,245 to 20,292). A 71% increase in Ireland has taken the total population from 26,467 in 1983 to 34,544 in 1988. Protection under the Wildlife and Countryside Act 1981 has been the main reason for the increase. Elsewhere in Scotland the distribution, scattered over 34 different islands, showed some marked changes, in particular a decline in the Outer Hebrides and an increase on the islands off the north and west coasts. These changes are discussed in relation to the amount of sheep grazing and suitable grassland on these islands. Photography was used to verify many of the aerial counts, and revealed an acceptable level of accuracy. Introduction The three populations of Barnacle Geese to the Blasket Islands, in Co. Kerry, south Branta leucopsis breeding in arctic USSR, west Ireland. Although the majority of the Svalbard and East Greenland winter population winters on the island of Islay, respectively on the North Sea coasts of birds have been found at over 100 different Continental Europe, the Solway Firth haunts within this extensive range, all but (Scotland/England) and in north and west a few being offshore islands which are Scotland and western lreland. Extensive mostly uninhabited. marking with individual leg rings and Away from Islay, the only practical conventional metal rings has shown virtual method of determining how many geese are separation of the three populations, with inhabiting this extensive range is to count just a handful of birds in any year moving them from the air. Visiting even a from one to another (Ogilvie & Owen 1984). proportion of the haunts by boat within a Censusing of the three populations is reasonable time would be a major most easily done in winter, the Arctic undertaking. Percival (1988) and Newton & breeding areas being extensive and of Percival (1989) showed from studies of varying accessibility. Wintering populations individually marked geese that there is some on the Continent and on the Solway are movement during the winter between Islay concentrated and regular counts can be and Tiree/Coll, and perhaps other haunts, made. The third population, from East so it is essential that any census is carried Greenland, is highly scattered in winter, out in as short a time as possible. from Orkney in the northeast of Scotland The technique of counting this 2 AD. Fox et al S8 16 (1) population from the air was pioneered in the the breeding grounds (Fox & Gitay 1990). late 1950s (Boyd 1968) and is now well The relatively small size of the established (see Methods). For reasons of population, its restricted distribution and its cost, however, such surveys have been variability in breeding success, all make the carried out only at about five-year intervals East Greenland Barnacle Goose vulnerable (e.g. Boyd 1968, Ogilvie & Boyd 1975, to hunting as well as to modification or loss Ogilvie 1983a). of habitat. On Islay, where 50 - 700/0 of the total There has been conflict in some parts population winters, ground counts have of Islay between farmers and conservationists been carried out every winter since the concerning the large wintering flocks of mid-1950s, often twice a winter and more Barnacle Geese there. In the late 1970s, an recently monthly (Ogilvie 1983b; Easterbee increase in formerly low levels of shooting & Bignal 1983 -1988, Bignal et 01 1988). brought about a marked reduction in These counts monitor a major segment of numbers (Ogilvie 1983b). In 1981, the the population which, as the aerial surveys Wildlife and Countryside Act gave the have shown, dominates changes in the species full protection. Shooting under population total. Age-ratio counts are also licences issued by the Department of carried out on Islay each autumn to assess Agriculture and Fisheries, Scotland, to breeding success. prevent serious agricultural damage was at Elsewhere, there is a long series of a lower level than before and numbers have ground counts from the principal Irish increased again (see below). In 1983, the haunts of Inishkea, Co. Mayo (Cabot & Royal Society for the Protection of Birds West 1983) and Lissadell, on the mainland purchased a large part of one of the most near Sligo (Irish Bird Reports). Sporadic favoured feeding areas, at Loch Gruinart, counts have taken place at some Scottish and began management specifically for haunts, more regularly in recent years, geese. notably Colonsay, Coli and Tiree, and The 1968 Countryside Act empowers islands in the Orkney group (Scottish Bird the Nature Conservancy Council to offer Reports). These counts have, however, management agreements to owner/occupiers never been sufficient to enable any within Sites of Special Scientific Interest· judgements to be made concerning the (SSSIs). Three SSSIs have been designated status of that part of the population that on Islay as Barnacle Goose sanctuaries and winters away from Islay. farmers within these have management The Barnacle Goose is the subject of agreements which provide payments and, in special conservation measures concerning some years, free fertiliser in return for habitat protection under Article 4 of the maintaining a required area of reseeded EEC Directive on the Conservation of Wild rotational grassland and agreeing not to Birds, which obliges member states to take shoot or deliberately scare the geese. account of "trends and variations in The three SSSIs, which include the population levels" ensuring "their survival RSPB Loch Gruinart Reserve, attract and and reproduction in their area of hold an increasing proportion of the island's distribution". It has long been known that Barnacle Geese (Percival et 01 1988, there are considerable annual variations in Easterbee & Kinnes 1989). These important the breeding success of Arctic nesting geese, changes on the major wintering haunt may which can have a major effect on population be affecting the pattern of numbers and totals. Breeding success variation in the East distribution elsewhere and merit further Greenland Barnacle Geese, as with other investigation. species, is linked to meteorological Several of the traditional wintering conditions on the wintering grounds, as well haunts of Barnacle Geese away from Islay as at staging areas used on migration and also qualify for protection as EEC Special 1990 East Greenland Barnacle Geese in Scotland 3 Protection Areas and "Ramsar" sites of overflown as well as every other island on International Importance. They qualify by which the vegetation looked suitable for virtue of the number of geese present and geese. It is quickly apparent from the air if the proportion these represent of European an island has areas of grass on which the or world populations, providing a need for geese can feed or is covered in rank regular information on these haunts. vegetation or bare rock to which they are Since Barnacle Geese prefer short unlikely to be attracted. Likely-looking grassland swards on which to feed, the areas on the mainland coast, and on the suitability of offshore islands is determined coast of the larger, inhabited islands, such largely by the presence of sheep or cattle. as the Uists, Benbecula and Skye were also Historically, these were taken out to graze covered. through the summer on many of the small, An assessment was made of the number uninhabited islands off the west coast of of sheep or cattle present on each island, Scotland. In recent years, twice-yearly and the proportion of the island that compulsory dipping of sheep may have appeared to be short grassland sward.