Movements of Tits in Europe in 1959 and After by Stanley Cramp
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Movements of tits in Europe in 1959 and after By Stanley Cramp INTRODUCTION AN EARLIER PAPER (Cramp, Pettet and Sharrock 1963) described the irruptions of Great, Blue and Coal Tits (Parus major, caerukm and ater) into the British Isles in the autumn of 1957 and showed that these formed part of considerable movements of all three species over large areas of western and central Europe, Although the Coal Tit was known to be an irruption species in some parts of Europe, it had not been generally realised that Great and Blue Tits, normally continued... 237 BRITISH BIRDS sedentary birds, also move considerable distances at times of peak population. The examination of earlier observations showed that such movements had occurred on a large scale at irregular intervals (in the British Isles the previous irruption of any size had been in 1949) and had probably varied in extent and nature in different years. There were again indications of irruption movements during the autumn of 1959, and, as before, appeals for relevant observations were made in ornithological journals and on the B.B.C In the event, the irruptions into the British Isles proved to be on a much smaller scale than in 1957, but over considerable areas of Europe they were much larger. In 1957 there was strong evidence that the irruptions were due to the high numbers of tits surviving in the previous mild winter, and in 1959 also tit numbers appear to have been unusually high, due both to a mild winter in many countries and to a good summer which resulted in a high fledging success. Census figures for two areas in England and one in Holland show, however, that numbers of Blue and Great Tits were again very high in the 1961 breeding season, reaching record levels in two of the areas, yet the irruption movements which might have been expected in these countries in autumn did not occur on any large scale. Some possible reasons for this are examined. MOVEMENTS IN THE BRITISH ISLES In 1957 movements and increases of Blue, Great and, to a much smaller extent, Coal Tits were noted in the British Isles after the breed ing season, and they were followed by an influx of all three species on the east and south coasts of England from mid-September onwards. The pattern was similar in 1959, but on a smaller scale, especially among the native populations. From mid-June, but mainly in July and August, small numbers of tits, mostly Blue, were seen at observa tories on the south and east coasts of England where they are not normally present in the breeding season; inland, increased numbers of Blue and Great Tits were trapped at Godalming (Surrey) in August, while the first wanderers appeared in central London at the end of the month. The first sign of any movement into the country was at Dungeness (Kent) on 4th September, when two Continental Coal Tits were trapped. In the late evening of the 14th another appeared and there were eight more on the 15th; then on four days from 23 rd September to the end of the month small numbers (six to fifteen) were reported, and all trapped or observed closely were believed to belong to the Continental race. Numbers of this species at other observatories were small: Sandwich Bay (Kent) reported some Continental birds on 16th September; there were two only at Gibraltar Point, on 28th; singles were identified at Cley on various days from the nth (with three on 238 TIT MOVEMENTS IN EUROPE IN I959 AND AFTER the 24th); at least three different Continental birds were recorded at Portland (Dorset) from the 14th; and, further west, a single Coal Tit was seen at St. Agnes (Scilly Isles) from the 19th to the zist. Some may have moved inland, for in central London, where the species breeds only occasionally, three were seen in the gardens of Lambeth Palace on the 7th and seven on the 9th, when there were also twelve in Regent's Park. Small numbers were seen in these two places later in the month and during the third week of September a few were noted at Broomfield (Kent). Much further north, some were observed at Grune Point (Cumberland) between 13th and 26th September, but it seems unlikely that these can have been connected with the small irruption in the south. In the first half of September, a few Blue and Great Tits were recorded at various observatories, but it seems probable that these and others on the coast were, like those in August, wandering local birds. The first large increases were of Blue Tits—on 17th September at Gibraltar Point (12); on the 19th at Sandwich Bay (20) with 25 on the 20th and 50 on the 30th; on the 20th at Selsey Bill (Sussex); on the 24th at Dungeness (ten, rising to 30 on the 26th), Portland (11, with 23 on 25th and 38 on 26th) and Spurn (12, with ten on 28th). At Pevensey Marsh (Sussex) there was a big increase of Blue Tits on the 24th and 25 th, with considerable numbers a few miles inland on the 26th. Radar observations showed a moderate passage of birds then between west and north-west across the Straits of Dover from the Pas de Calais area, most continuing inland on reaching the Kent and Sussex coasts; that night there was again a north-west movement, and J. L. F. Parslow (in liti.) considers it possible that both may have involved tits. In the last week of September a moderate westerly movement of Blue Tits was observed at Cley (Norfolk). Inland records, however, were comparatively few and restricted mainly to south-east England. There were moderate movements at Broomfield in the third week of September and in central London numbers increased, reaching a maximum of 21 on the 23 rd in the built- up area and of 22 on the 22nd in Regent's Park. In north-east England, Blue Tits were seen on the coast at Redcar and Filey (York shire), where there was a southerly movement on the 24th, and in the town centres of Redcar and Middlesbrough (Yorkshire). Movements of Great Tits in September were on a smaller scale, with ten at Sandwich Bay on the 20th (and 20 on the 30th), and a maximum of 25 at Dungeness on the 26th; there were only very small numbers at Portland, Gibraltar and Spurn, and none at Cley. Inland reports were correspondingly few, with a small passage at Broomfield, odd birds in central London and an increase at Nuneaton (Warwickshire). In October Coal Tit movements appeared to have died out at most 239 BRITISH BIRDS observatories after the first few days, though two were seen at Flam- borough (Yorkshire) on 10th October, and small numbers occurred at Cley until the 22nd and at Folkestone (Kent) until the 19th. In the Isles of Scilly four birds of the Continental race were identified on 3rd October and one on the 7th, while there was one at Cape Clear Island, off the coast of southern Ireland, on the 6th and again on the 1 ith. Williamson (1959) stated that in the early days of October high pressure over the Continent, giving east to south-east winds over western France, led to a drift-invasion at these two observatories at this time. Blue Tit numbers at Gibraltar Point were small in October, after a peak of 40 on the 2nd, and at Spurn also, though the species was numerous at Tetney Marsh (Lincolnshire) on the 10th. At Cley the moderate westerly movement ceased after 4th October. There was a little more activity on the south coast of England, for although Dungeness had only one small peak (15 on the 6th), Sandwich Bay reported more than ten on 1st, 9th and 14th October, and Portland over twenty on 3rd October and twenty on the 13th. On the 5th about two hundred Blue Tits, with some twenty Great, were seen on the Sussex coast near Pevensey Bay, Eighty or more were recorded at Warden (Kent) on the nth, about 50 at Pevensey on the 13th and a small passage at St. Margaret's Bay (Kent) as late as the 23rd. Inland, moderate numbers occurred in central London throughout the month and there was some increase at St. Albans (Hertfordshire) on the 20th. In early November small increases in Blue Tit numbers were observed at places on the Kent coast and in central London, and there was five-fold increase at this time at Malham Tarn, well inland in Yorkshire, which lasted well into the month. Records of Great Tit movements in October were few. Spurn had small numbers, with a peak of about ten on the 10th and 1 ith, but Gibraltar Point had none after the 2nd and Sandwich Bay none after the 1 st. Some occurred at Dungeness and Portland (maximum 12 on the 13 th), and 30 were seen at Pevensey on the 13 th. Except for slight increases in central London there were no inland reports of this species on the move. In 1957 there was an increase of all three species of tit at many west coast observatories some days after the invasion of the east and south coasts of England, suggesting that many, perhaps with some British birds, had moved north and west across the country. There was little evidence of this in 1959. Only odd Blue Tits were seen on single days at some west coast observatories—Hilbre, Calf of Man and Skokholm (though they were said to be in every gulley on the south coast of Pembrokeshire on the 13th)—and none was reported at Bardsey or the Irish observatories of Great Saltee, Copeland and Tory Island.