96 Wildfowl Barnacle Geese in the west of Scotland, 1957-1967 HUGH BOYD Introduction Such an approach was clearly useless for Twenty years ago it appeared to most of reliable assessment of population changes. the few people with substantial know­ The only practicable alternative appeared ledge that the Barnacle Goose Branta leu- to be an inspection of the islands from the copsis had decreased considerably as a air, a somewhat costly method about wintering bird in Scotland. That belief which litde was known in Britain. led to a successful attempt to have the After some preliminary exercises in the Barnacle Goose excluded from the list of techniques of aerial observation in 1956, birds that might be shot under the Protec­ a first survey of the Hebrides was made tion of Birds Act, 1954, effective on 1st in 1957 (Boyd and Radford 1958). A January 1955. On 18th November 1955 second aerial survey of British Barnacle the Secretary of State for Scotland issued Geese, including those in Ireland as well an Order which allowed the geese to be as in Scotland, was conducted in 1959 as shot in the months of December and part of an international assessment of the January on ‘ those islands which are entire population of the species (Boyd situated within any of the counties of 1960). Subsequent surveys were made in Argyll, Inverness and Ross and Cromarty 1961, 1962, 1965 and 1966. This paper and which lie off the mainland of the said has the limited objectives of making the counties and to the west of longitude 5 results of the aerial surveys generally degrees west Only those Barnacle Geese available, using them to find how the frequenting islands off the coast of Suther­ Hebridean stock of Barnacle Geese has land and those wintering on the Solway fared during the last decade and investi­ Firth continued to enjoy total legal pro­ gating whether the lack of total legal tection after November 1955. This dis­ protection has had the serious conse­ appointing and potentially dangerous quences that were feared. decision made it urgent to obtain detailed Boyd (1960) inferred from the re­ information on the numbers of Barnacle coveries of ringed geese that there were Geese in different pans of Scotland and three populations of Barnacle Geese which to follow their changes over the years. mixed very little. Those breeding in No attempt at a census had been made Siberia winter in Germany and Holland; before 1955, because the geese were those from Spitsbergen winter on the widely scattered through the Hebridean Solway Firth; and those breeding in east islands, many difficult of access and no Greenland winter in the Hebrides and longer permanently inhabited by man. Ireland. Later ringing, and comparisons The only estimates of population size of the proportions of first-winter birds in were derived from adding together infor­ different flocks, have confirmed this pic­ mation, much of it second-hand, obtained ture, although there is a puzzling dis­ in a haphazard way by a variety of crepancy between the numbers wintering recorders over an indeterminate period. in Germany and Holland (some 20,000 in Barnacle Geese 97 recent years) and the few small breeding There are several hundred islands in colonies known on southern Novaya the Hebrides. Before embarking on the Zemlya and Vaygach Island (Uspenski first aerial survey it was possible, after 1965). Jennov (1963) reviewing the breed­ talking to people with local knowledge ing distribution in east Greenland, con­ and searching for published records, to cluded that the Barnacle Geese occurring prepare lists of islands where Barnacle there were more than enough to account Geese had or had not been seen. There for the numbers reported from Ireland remained a formidable number lacking and north-west Scotland, and supposed records, so that all the surveys involved that the excess might be fortifying the ‘ exploration ’ as well as journeys to known continental stock. That seems unlikely haunts. Rather reassuringly, the number because 1,236 Barnacle Geese had been of newly-discovered haunts was quite ringed in Holland by the end of 1966 and small and nearly all the islands found un­ 2,396 in Greenland between 1955 and suitable on the early surveys continued 1964: 97 recoveries of Dutch-ringed and to lack geese. over 140 of Greenland-ringed geese have Though in principle all the islands in been reported without providing any the Hebrides likely to hold Barnacle evidence of movement between Greenland Geese can be inspected from the air, there and Holland. There is a single sight are many practical difficulties in arranging record of a Barnacle Goose, colour- comprehensive itineraries. Searching has marked in east Greenland in July 1963, to be carried out at low altitudes and slow in the Groningen province of Holland on speeds, and it was necessary to hire the 20th March 1966. The present strength cheapest light aircraft, which, inevitably, of the Hebridean-Irish group seems to be has relatively limited endurance. There consistent with Jennov’s assessment of are very few airfields in the west of Scot­ the situation in Greenland, and other ex­ land and suitable fuel is available on planations must be sought for the dis­ demand at only Prestwick, Ayrshire, and crepancy between the Russian and Dutch Stornoway, Lewis. The weather in the evidence. area is often unsuitable for light aircraft Since it is still uncertain to what extent and cannot be forecast accurately, since the Greenland stock breaks up into sub­ most of the relevant weather systems are populations with distinct wintering areas, arriving from the Atlantic Ocean where counts from Ireland in 1959, 1961, 1962 the recording network is thin. Winds of and 1966 are included here. Only the only moderate strength (15-25 knots) can total numbers are used. The details will make an appreciable difference to the be included in a report on the distribu­ performance of a light aircraft and add tion of Barnacle Geese in Ireland being greatly to the difficulty of manoeuvring at prepared by Mr. D. B. Cabot. low altitudes particularly in the vicinity Inventory methods (Plate IX, facing p. of steep-sided islands. No two surveys 108) were conducted in the same sequence, Conducting an inventory of geese in their but care was taken to keep track of shifts winter quarters poses two problems : of geese from one island to another close finding the geese and counting them. by. There is no evidence of frequent Finding the geese requires that you know long-distance movements between winter where to look and that having reached quarters. The first aerial survey was made the place you can then detect the geese. in February, the second in late November The Hebridean Barnacle Geese are much and early December. Those periods were easier to find from the air than, for ex­ chosen as being times when migratory ample, grey geese in central Scotland, movements were unlikely. The opera­ because they mostly live on small islands tional penalties of very short days, poor and the areas of grass on which they light and a high proportion of days when might be feeding are even smaller. Pro­ flying was not possible were so great that vided there is enough light to see the the later surveys were carried out in time of day when they are looked for is March or April. The greater risk of migra­ unimportant, because ¿ie geese roost and tory shifts in early spring seems to have feed in the same place. On the few parts been unimportant and the increase in of the Scottish mainland used by Barn­ operating efficiency was considerable. acle Geese and on the larger islands, par­ The most obvious gain was in the ticularly Islay, searching is more difficult ability to take photographs of goose flocks because the possible sites are less re­ and so obtain checks upon the counts stricted and the geese fly from roosts, and estimates made by the observer and usually on offshore islands or sandbanks, pilot. One of the great merits of the to grasslands of several types. highly dispersed distribution of Barnacle 98 Wildfowl Geese in the Hebrides is that few of the from place to place in the course of a flocks encountered exceed five hundred survey. birds and many are less than one hun­ Long-distance movements of geese were dred. Thus it is often possible to enum­ unlikely to be substantial enough to erate the birds individually or to estimate vitiate the results, largely because of the by groups of ten. That is important for brief duration of the surveys. The exten­ the opportunities for counting are fleeting. sive replication of counts that would be A likely place for Barnacle Geese is needed was too costly for the limited approached at 400-600 feet above the sea, budget. Indeed routes were laid out to low enough to cause the geese to lift off avoid covering the same ground twice, and the ground but not so low as to make only seven pairs of repeated counts are them scatter in alarm or to make hand­ available. In February 1957 repeat visits ling of the aircraft awkward. The pilot at intervals of between five and ten days attempts to keep the entire group of geese were made to Islay, the Treshnish Isles, clearly visible, preferably to both the Gunna and Gasker (Lewis); and the totals observer and himself, for long enough for the first and second visits were 1,600 to allow a count to be repeated two or and 2,400 respectively. In 1959, visits to three times. The flock is not closely Loch Bee, South Uist, yielded 21 Barn­ pursued because that would alarm the acle Geese on 26th November and 110 birds unduly, which is objectionable in on 3rd December.