Search

Three black kite (Milvus migrans migrans) pulli (siblings, BK1, BK2, and BK3) from the same nest in eastern Slovakia were tagged with telemetry (GPS/GSM) loggers on 1 July 2016. BK1 (female), BK2 (male) and BK3 (female) occupied post-fledging areas until 12 August 2016 when they began to migrate southeast. BK1 wintered in Libya, returned to Turkey in the summer, then wintered in Israel. After spending the winter there, it returned to Europe, looped the Baltic Sea and stayed in western Russia throughout the summer. During the autumn, it passed Ukraine and travelled along the Black Sea and wintered in Syria then it moved again to Europe. It used 18 temporary settlement areas (TSA) during its journey until 12 June 2019 when it was roadkilled in Norway. BK2 migrated to the northern tip of the Red Sea and crossed the sea where positions of the bird spatiotemporally coincided with a position of transcontinental cargo ship. It is expected that the bird died whilst on the cargo ship and its body was passively carried on-board and discarded on the west coast of the Red Sea. BK3 reached the northern outpost of the Red Sea in Saudi Arabia. It then continued southeast along the east coast of the Red Sea to Yemen and crossed the Strait of Bab-el-Mandeb to Africa. It wintered mainly in Sudan, Southern Sudan and Uganda, then returned along the west coast of the Red Sea and the east coast of the Mediterranean Sea arriving to the Turkey/Syria border area. Only two TSA were revealed on its route. The migration behaviour among these floaters during natal dispersal was substantially different and covered surprisingly large parts of Europe and North and East Africa.

We characterized the spatiotemporal activities in winter grounds of Red Kites originated from central Europe and wintering in south-eastern Europe. We found not only Red Kites at these places but often also Black Kites Milvus migrans. Birds arrived to winter grounds in Hungary, Croatia, and Greece from 10 July to 12 December (median 22 October) and departed from winter grounds between 14 February and 22 May (median 14 March), thus staying at winter grounds from 121 to 229 days (median 145, mean 161 ± 43 SD, n = 14 cases). We usually found a number of Red Kites wintering together at winter grounds, although some Red Kites wintered alone. We found Black Kites wintering together with Red Kites at the same winter grounds in 6 out of 14 cases. The numbers of Black Kites wintering together with Red Kites were higher than the number of Red Kites at all Greek winter grounds. At winter grounds in Hungary and Croatia, the numbers of Black Kites were lower than the numbers of Red Kites or Black Kites were wholly absent. If we regarded kernel density estimate 80% (area of main foraging and roosting activities) as the best indicator as to the size of home range, we revealed that the size of a home range for birds staying at one place through the entire winter was from 10 to 108 km2 (median 72, mean 60 ± 36 SD, n = 12 cases) and that the size of home range for birds with local shift(s) in winter grounds was from 344 to 620 km2 (median 434, mean 466 ± 115 SD, n = 3 cases) which is substantially larger than the size of home ranges published to date for Red Kites wintering in central and south-western Europe.