THE AUTUMN MIGRATION OF SOARING BIRDS AT THE BOSPHORUS

The migration of soaring birds was observed at Küçük Çamlica at the southern end of the Bosphorus between 14 July and 8 November 1966. Simultaneous watches were also carried out at other points on the Bosphorus on a number of dates. The largest movements of birds of prey occurred on days of light northeasterly winds, the largest movements of storks on days of light winds with a southerly component. On most days the stream of migrants appeared to be concentrated over the southern end of the Bosphorus. Migration frequently occurred right throughout the day, though the peak period was usually not spread over more than three hours. Figures are given for the daily times of migration of the commonest soaring birds. Daily counts of soaring birds (storks, raptors and Cranes) migrating over the Bosphorus at Küçük Çamlica are given. The main species found migrating were (with total number recorded in brackets) White Stork Ciconia ciconia (207,145), Black Stork C. nigra (6,194), Honey Buzzard Pernis upivorus (8,997), Buzzard Buteo buteo (12,949), "Spotted" Eagle Aquila clanga/pomarina (4,309) and sparrowhawk Accipiter nisus / brevipes (5,224). The autumn migration of 1966 is discussed in detail in a systematic list. Buzzards B. buteo were recorded in large numbers for the first time at the Bosphorus, and were the commonest bird of prey. Cranes Grus grus were also recorded for the first time. Comparison is made between our results and those of previous workers, though differences of coverage rule out any firm conclusions.