Autumn Observations on the Bosphorus and Dardanelles.

Summary. Migration was studied in the Bosphorus‐Dardanelles area between 11 September and 1 October 1956. On most days observations were made at two or more places Daily counts of migration of soaring birds are given. Honey Buzzards Pernis apivorus crossed the Bosphorus on a front up to ten miles wide, and not more than a fifth or a tenth of the total could be seen from any one point. Some other species passed in narrower streams Different species of birds of prey passed to a large extent by different routes Moderate cross‐winds deflected the streams of soaring‐birds (especially eagles Aquila spp.) downwind Diurnal migrant passerines passed in large numbers through the western half of the area; the migration was on a broad front and often inconspicuous. In the Bosphorus area passerine migration was frequently towards the northwest Very large, fluctuating numbers of night‐migrants were seen along the Bosphorus, but fewer in the Dardanelles area It is thought that European Turkey is an important area of concentration for some northern passerine species Some water birds were seen following the Bosphorus southwards The apparent changes in the abundance of some of the migrant species over the centuries are discussed in an appendix