British Birds
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Volume 64 Number 9 September 1971 British Birds North American waterfowl in Europe Bertel Bruun INTRODUCTION The natural occurrence of North American birds in Europe is a well- established fact substantiated by recoveries of ringed birds. The transatlantic crossings of waders and passerines have been excellently treated by Nisbet (1959, 1963) and, more recently, by Sharrock (1971). The waterfowl (Anatidae) have received less attention, however, and no attempt has previously been made to summarise their occurrences in Europe in relation to their migrations and distributions in North America. Analysis of the data on waterfowl is greatly complicated by the many escaped birds encountered so much more often in this family than in any other, which might explain the scanty treatment of trans atlantic vagrancy among this otherwise intensively studied group. Counterweights to the complication of escapes are the fairly large size and easy identification of ducks and geese, the many specimens obtained, and the relatively high rate of ringing returns. In this paper the records of Nearctic waterfowl in Europe are briefly discussed in the light of the distributions, migrations and habits of the species and subspecies concerned in North America. All dated records up to and including 1968 have been considered; undated records and any of birds seriously regarded as escapes have generally been excluded. So far as possible, all the records are listed with refer ences, but in some cases, particularly where there are more than ten in any country, they are summarised or tabulated by the months when they were first reported. Because of the establishment of feral popula tions in Britain and Sweden, the Canada Goose Branta canadensis has been omitted, although since about 1954 there have been a number of records of individuals of one or other of the small subspecies in Ireland (chiefly on the Wexford Slobs) and in Scotland (chiefly in the Hebrides) which seem almost certain to include genuine transatlantic 385 386 North American waterfowl in Europe vagrants. Indeed, Merne (1970) has recently listed 38 Irish records involving 75 birds, at least 50 of them different individuals (ignoring the possibility of the same one reappearing in successive years), in every winter since 1954/55 except 1959/60 and 1964/65. Because they were associated with newly arrived Greenland White-fronted Geese Anser albifrons flavirostris, because the small arctic races were regularly involved, and because there was evidence of hybridisation with a Barnacle Goose B. leucopsis and with Snow Geese A. caerulescens, he concluded that 'most, if not all, of the Canada Geese wintering in Ireland are migrants from the north-west rather than vagrants from the east [i.e. Britain].' Britain and Ireland are treated together as a single geographical unit; the sources for these are Witherby et al. (1938-41), Kennedy et al. (1954), Bannerman (1957, 1958), Ruttledge (1966) and British Birds (abbreviated as BB) and the annual Irish Bird Reports (IBR). The Belgian records are taken from Avifaune de Belgique by the Com mission pour l'Avifaune Beige (1967) and the Dutch ones from Avifauna van Nederland by the Commissie voor de Nederlandse Avifauna (1970), as well as from the Belgian and Dutch journals Le Gerfaut, Aves, Ardea and Limosa. Most of the other Continental records are taken from the journals Alauda, L'seau, Nos Oiseaux, Dansk Ornitho- logisk Forenings Tidsskrift (DOFT), Vår Fågelvärld, Sterna and Rivista Italiana di Ornitologia, but those for Finland come from Merikallio (1958). The data for Greenland are from Salomonsen (1967). Informa tion on status in North America has been taken primarily from Snyder (1957), Stewart and Robbins (1958), Kortwright (1960), Bull (1962) and Godfrey (1966). REGULAR TRANSATLANTIC MIGRATION Seven species of waterfowl regularly migrate, or are believed to do so, from breeding grounds in Greenland to wintering grounds in north-west Europe (table 1). Two of the species involved (Pink-footed Goose Anser brachyrhynchus and Barnacle Goose Branta leucopsis) are primarily Palearctic, one (Eider Somateria mollissimd) is Holarctic but with an extensive gap in northern Asia, and the other four are cir- cumpolar or almost circumpolar in their distribution (see Johansen 1956, 1958, Vaurie 1965). It is also worth noting that they all cross the Atlantic between 6o°N and 70°N. The distance between east Greenland and Scotland, passing over Iceland, is about 1,000 miles, the longest stretch of water being the 500 miles from south-east Iceland to the Outer Hebrides. The distance between the southern tip of Greenland and suitable wintering grounds for geese in the mid-Atlantic states of North America is at least 2,000 miles, further even than the distance between west Greenland and Scotland, and again the longest ocean crossing, from Greenland North American waterfowl in Europe 387 Table 1. Breeding and wintering areas of three ducks and four geese which regularly migrate across the Atlantic (or are believed to do so) and evidence for this to the end of 1968 All scientific names are given in the summary on page 407 Species Breeding Wintering Evidence: remarks Eider (northernmost race) North-east Iceland 1 ringing recovery: Greenland probably only small part of population King Eider East Iceland 1 ringing recovery: Greenland probably only small part of population Red-breasted Merganser East Iceland, Britain None: assumed by Greenland and Ireland Salomonsen (1967) Greenland White-front West Britain and 203 ringing recov- Greenland Ireland eries Pink-footed Goose East Britain and 3 ringing recoveries: Greenland Ireland wintering unknown in New World Pale-bellied Brent Goose North Britain and None: assumed by Greenland Ireland Salomonsen (1967) Barnacle Goose East Britain and III ringing recov- Greenland Ireland eries to Labrador, is about 500 miles. Transatlantic migration in these species is therefore only to be expected as it follows the shortest possible route to suitable wintering grounds. For the two primarily Palearctic geese this migratory pattern is further strengthened by the original route of westward spread (Johansen 1956, 1958). Other Greenland waterfowl winter much farther north and long-distance migration is not necessary to their survival; thus for these species it is beneficial to remain on the western side of the Atlantic. VAGRANT NORTH AMERICAN WATERFOWL Black Duck Anas rubripes Of the four records of Black Ducks in Europe to the end of 1968, three were in Ireland and one in England: About 5th February 1954 , Mullinavat, Co. Kilkenny (IBR, 1954; BB, 48: 341) i8th-2ist February 1961 1, North Slob, Co. Wexford (IBR, 1961; BB,54: 324-325) 27th November 1966 , Mayglass, Bridgetown, Co. Wexford (IBR, 1966) 18th-20th March 1967 , Yantlet Creek, Stoke, Kent (BB, 60: 482-483) As the Black Duck is one of the most abundant dabbling ducks in eastern North America (Kortwright 1960, Bull 1962), it is surprising that it has not been reported more often. It is migratory, but only to a limited degree, breeding from the west side of Hudson Bay and 388 North American waterfowl in Europe Labrador south to North Carolina and wintering from as far north as Newfoundland south to the Gulf coast. Those in February and March occurred at about the time when spring migration is just beginning and westerly gales are commonplace. The species has never been recorded in Greenland. Green-winged Teal Anas crecca carolinensis There seem to be 52 dated records (involving 55 individuals) of Green- winged Teal in Britain and Ireland to the end of 1968. Their monthly distribution is shown in table 2. Geographically they are spread rather evenly, with minor concentrations in south-west Ireland and south-west England. On the other hand, there have apparently been only seven records on the Continent: 28th April 1937 , Z.H.-Biesbosch, Netherlands (Limosa, 35: 206) 29th April 1954 , Närke, rebro, Sweden (Salomonsen 1963) 29th March 1961 , Merkem, Oostvlaanderen, Belgium {Gerfaut, 53: 68; Aves, 5: 76) 20th March 1962 , St Jan Steen Z., Netherlands {Limosa, 35: 206) 28th March and 26th , Harchies, Hainaut, Belgium {Gerfaut, 55: 458; Aves, 5: April 1965 75) IIth-14th April 1965 , Wassenaar, Netherlands {Limosa, 40: 17) 27th November 1965 , Monster, Netherlands (Limosa, 40: 17) In addition, one was recorded in Morocco, 100 km south of Casablanca, on 13th April 1959 (Frété 1959). It is surprising that so few have been reported outside Britain and Ireland, but this will undoubtedly change as observation becomes more intensified on the Continent. The Green-winged Teal is a common duck in North America where it under- takes rather extensive migrations: it breeds in the north from Hudson Bay to Alaska and winters in the southern United States, Mexico, northern Central America and the West Indies, including the length of the Atlantic coast north to Massachusetts. It has occurred several times in Greenland: twice in May (probably due to prolonged spring migration) and once in each of the months September to December (Hørring and Salomonsen 1941, Salomonsen 1967 and in litt.). Table 2, Monthly distributions of dated records of ten American ducks in Britain and Ireland to the end of 1968 The number of individuals, where different, is shown in brackets. Some birds have remained over two or more months and in such cases only the first month is taken, Similarly, the Ring-necked Ducks which have reappeared in two or more successive years are entered for the first year only. All scientific names are given in the summary on page 407 Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Black Duck - 2 1 - - - - - - - 1 - Green-winged Teal 7 6 9 10 2 - - - - 6(7) 8(9) 4(5) Blue-winged Teal 3 1 1 3 - - - - 6(7) 4(5) 3 2 American Wigeon 5(6) 4(6) 5 1 1(2) 1 - - 1 4(16) 6 5 American Pintail - - - - - - - - 2 - - - Ring-necked Duck 3 j 3 2 - - - - - - - - Bufflehead 1 2 - - 1 - - - - - - Surf Scoter 4 5(8) 3(4) 1 - 1 - 1 5(6) 9(15) 5(7) 10(11) Black Scoter - - - - - - - - - - 1 1 Hooded Merganser 1 - - - - - I - - - - 2 390 North American waterfowl in Europe Analysis of the European records is complicated by the fact that only drakes in full plumage are distinguishable from European Teal A.