Franklin's Gull in Hampshire: a species new to Britain and Ireland D. F. Billett and P.J. Grant Plates 50-51 At 16.40 on 21st February 1970 J. T. Smith and D.F.B. were at the southern tip of Farlington Marshes, Hampshire, when a small, dark- winged gull approached low along the shore and settled immediately in front of them about 100 yards away. They were able to watch it for about ten minutes before it circled and flew off. During this time it made several short flights of a yard or two when harassed by Black-headed Gulls Larus ridibundus near-by. Several features suggested that it was something unusual. It was slightly smaller than the Black- headed Gulls and its mantle was rather dark grey. Its bill was short, stout and blackish; its dark red legs were also short and this accen­ tuated a hunched appearance. The bird had an incomplete black hood and was presumably acquiring summer plumage. In flight its tail appeared pale grey down the centre, contrasting with a pure white rump. Most startling of all, however, was its wing pattern in flight: a rather small black tip, with a white terminal spot or spots, separ­ ated from the dark grey of the remainder by a broad white area across the primaries which joined a continuous white border along the trailing edge. Both observers had previously seen the first-winter Laughing Gull L. atricilla which stayed in the Weymouth area of Dorset from 17th February to 6th October 1969 (Brit. Birds, 63: 279, plate 50) and at first they thought that this might be an adult or near-adult of that species. These suspicions were quickly dispelled, however, when they both remarked on the evident structural differences of the bird at Farlington. The Laughing Gull had been nearer in size to a Common Gull .L. canus, certainly larger than a Black-headed, and because of its long legs had stood higher than either species. Its bill, too, had been noticeably long and stout. Unless there was an improbably great variation in structural features of Laughing Gulls, they were certain that this must be a different species. The conditions for observation and comparison with other gulls were ideal and the observers were con­ fident that they would be able to make an identification from the appropriate literature. Albrektsson and Lindberg (1967) briefly described the field-characters of the adult Franklin's Gull L. pipixcan

310 Franklin's Gull in Hampshire 311 and this appeared to fit precisely; more detailed works of reference, particularly Dwight (1925), confirmed this identification and it was possible to determine the age as second-winter or older. This was the first record of the species in Britain and, indeed, anywhere in the Old World. The Franklin's Gull was not located again until 1st March, but it was then seen regularly in the area of Farlington Marshes until 16th May. News of its presence soon spread and Farlington quickly became an essential destination for birdwatchers from all over Britain: during the following weeks many hundreds must have gone there, including P.J.G. who was able to make very detailed sketches and notes. The bird seemed to establish a regular pattern of movement during the daytime: with other local gulls it would visit a marsh lagoon during the early morning, then move a short distance inland to a feeding area of playing fields, rough pasture and adjacent factory sites, and in the evening again visit the lagoon where it would bathe and preen before flying off in a south-westerly direction. Where it roosted was never discovered.

IDENTIFICATION J. B. and S. Bottomley's excellent photographs (plates 50-51), which were taken on 19th March, should be compared with their shots of the first-year Laughing Gull in Dorset (Brit. Birds, 63: plate 50) and with those of adult and immature Laughing Gulls by Allan D. Cruickshank and Peter Lindberg (Brit. Birds, 60: plates 17-19). The smaller size and shorter bill and legs of the Franklin's have already been referred to: these structural differences would be particularly important in the separation of immatures, which are more difficult to distinguish on plumage features alone. The adults of the two species have more striking distinctions. The pale grey centre to the otherwise white tail, just visible in plate 50, is not shared by adult Laughing Gulls and, indeed, is unique among adult gulls, but by far the best feature for separating the adults in the field is the upperwing pattern. The dark grey of the Laughing Gull's inner wing shades evenly to the black wing tips, and the only white areas are a prominent white line along the trailing edge and some small white terminal spots on the primaries, the latter often missing in worn plumage. In Franklin's Gull the white trailing edge to the wing leads into a white band extending across the primaries and separating the black wing tips from the dark grey of the inner wing; this distinctive pattern can be seen in plates 50 and 51. Dr Kenneth C. Parkes of the Carnegie Museum, Pittsburgh, Pennsylvania, has however stated (in litt. to P.J.G.) that a good series of skins of breeding Franklin's Gulls from Saskatchewan shows that the actual extents of the white area across the primaries and of the black on the wing tip are extremely variable and that this 312 Franklin's Gull in Hampshire apparently has no correlation with age among individuals in their second summer and older. He has also noted that the white terminal spots on the primaries, though usually more extensive in this species than in the Laughing Gull, are subject to substantial wear in spring. This latter point is of interest because, when discovered in February, the Franklin's Gull at Farlington clearly showed white tips to the outer primaries and, although these were still present at least until 8th March, they had disappeared by the 19th when the photographs were taken. This alteration in the wing pattern through wear continued and by 16th May even the black ends to the wings had almost com­ pletely vanished, apart from a very small tip to one primary on each side. The wings, as noted in the field, were rounded at the tip and rather broad, like those of a Common Gull, but the flight action appeared weak and rather faltering, with quick beats and angled wings rather reminiscent of a Kittiwake Rissa tridactyla. It has been suggested that this action may have been purely the result of sickness or the abraded state of the wings rather than a true field-character of the species.

MOULT At the beginning of March the Franklin's Gull began to show an uneven line to the trailing edge of the midwing, suggesting that it might be undergoing a moult of the outer secondaries, and at the same time two whitish patches appeared on the upper surface near the carpal joint, presumably caused by moult of some of the median coverts. By early April the mantle and wing coverts were in heavy moult. These observations were of particular interest as Franklin's is the only gull (with the possible exception also of Sabine's Gull L. sabini) known to have a complete moult twice yearly, in spring and autumn (others moult the wing and tail feathers once a year only, usually in autumn). No further signs of moult were noted, however, and the bird did not appear actually to renew any wing or tail feathers during its stay, the wings becoming more and more abraded. Incidentally, plate 50 clearly shows that the tip of the upper mandible was damaged; this injury seems to have been sustained after the bird arrived as J.T.S. and D.F.B. clearly noted a hooked tip to the bill when they first saw it on 21 st February.

DISTRIBUTION Franklin's Gull breeds colonially around lakes in the central plains of North America, from Iowa and South Dakota northwards to south­ ern Manitoba, Saskatchewan and Alberta. The choice of breeding site varies for no apparent reason from year to year and the size of a colony can fluctuate dramatically from none at all in one season to several thousands in the next. It is the only species of gull regularly breeding Franklin's Gull in Hampshire 313 in the northern hemisphere and migrating to winter quarters south of the equator. Although a few winter in the Gulf of Mexico and the Caribbean, and on the west coasts of Mexico and Guatemala, the main wintering area is much further south, on the Pacific coast of South America from Peru to southern Chile, On its spring migration north- wards the average arrival dates for various localities are given as: Minnesota, 4th April; Manitoba, 25th April; and Saskatchewan, 3rd May. In autumn the return migration is more erratic, but the first ones usually appear in Chile during September. There are also casual records from Hawaii and the Galapagos Islands in the Pacific, from the West Indies, and from the Atlantic coast of the United States (Bent 1921, Dwight 1925).

ARRIVAL IN BRITAIN Any discussion under this heading can, of course, be no more than speculative. In itself the occurrence of a Franklin's Gull in Britain is remarkable enough, considering its comparative rarity on the Atlantic coast of North America. The fact, however, that the one at Farlington apparently arrived in winter suggests that it had originated from further south, perhaps from the parts of its winter range in the Caribbean or Gulf of Mexico. Also, vagrancy would be more likely at that time of year as a result of the natural tendency of gulls to wander widely during the winter months. It is possibly no more than coin­ cidence that there were strong south-westerly gales along the British south coast in the week preceding the first sighting of the bird at Farlington, although these could well have contributed to its arrival. Another sighting of a Franklin's Gull in Britain 5 5 miles |to the east at Arlington Reservoir, Sussex, on 4th July 1970 (see 'Recent reports' in Brit. Birds, 63: 352, and subsequently accepted by the Rarities Committee) was no less remarkable; it was in fresh adult plumage, with full black wing tips and white terminal spots and, although it seems likely to have been a different individual from the one at Farlington, it is possible that the latter may have completed a wing moult between mid May and July.

REFERENCES ALBREKTSSON, T., and LINDBERG, P. 1967. 'Field-characters of the immature Laughing Gull'. Brit. Birds, 60: 159-160. BENT, A. C. 1921. Ufe Histories of North American Gulls and Terns. U.S. Nat. Mus. Bull. 113. Washington, D.C. DWIGHT, J. 1925. The Gulls (Laridae) of the World; their Plumages, Moults, Variations, Relationships and Distribution. Bull. Amer. Mus. Nat. Hist., 52: 63-401.

D. F. Billett, 61 Southampton Road, Fareham, Hampshire P. J. Grant, 120 Edward Street, London SE14 6DX