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Timing of the autumn migration of Black-throated Diver (Gavia arctica) in Ukraine. - V.N. Grishchenko. - Avifauna of Ukraine. 11. 2025. - Data for the period 1960–2025 were analyzed. The Black-throated Diver in Ukraine is a wintering and summering species, not only near the sea coast, but also in inland waters. Therefore, it is impossible to accurately distinguish the period of autumn migration, its boundaries are blurred. The time frame can be approximately determined using frequency diagrams. Reports of the first migrants may appear as early as August or early September, but the regular autumn migration of divers begins only in the third ten days of September. From the end of September, migration intensifies, the number of first registered birds steadily increases and reaches its maximum at the end of the second and beginning of the third ten-day period of October. Then their frequency decreases rapidly, in the first ten-day of November the beginning of migration is rarely noted, and for the second one there are only single observations of the first migrants. Regional differences in the timing of the beginning of autumn migration of Black-throated Diver in Ukraine are related to the spatial distribution of migrants. Their intensive passage goes down the Dnipro river. The earliest average dates in the northern part of Ukraine are in Kyiv region. Further south, a band of earlier migration onset is distinguished in regions along the Dnipro. Moreover, the birds «cut» the bend of the river and fly straight to the sea. Therefore, in Dnipropetrovsk region, the timing of their appearance is relatively late. The first migrating divers are also seen quite early on the lakes of Volyn. The early dates of the beginning of autumn migration are also in southern Ukraine, but here it is already largely associated with the movements of summering birds. In all regions, the average dates for the start of the autumn migration of Black-throated Diver fall on the second and third ten-days of October, the earliest ones – mostly on the second half of September and the first ten-day of October, the latest ones – on the third ten-day of October and the first half of November. The period of ending of the passage lasts from the end of October to the second ten-day of December. In most regions, the average dates of the last departure fall on the third ten-day of November, rarely – on the second half of the second ten-day, the earliest – on the end of October and the first half of November, the latest – on December. Changes in the timing of start and end of the autumn migration were not discovered. [Ukrainian].