Black Kites on a flyway between Western Siberia and the Indian Subcontinent

Abstract

The Black Kite (Milvus migrans) is one of the most widespread raptors in the world. The Palaearctic is populated by two migrating subspecies, Milvus migrans migrans and Milvus migrans lineatus, in the western and eastern part of this realm, respectively. There is a large intergradation zone of M. m. migrans/M. m. lineatus in-between. Although the migration routes of M. m. migrans from Europe to Sub-Saharan Africa and the Middle East are well known, detailed information about migration routes of Black Kites from intergradation zone are missing. Using satellite telemetry we are able to fill this gap in our knowledge of these birds. We tagged with GPS/SMS/GPRS telemetry loggers 13 and 6 Black Kite pulli in lowland around Biysk (Altai Krai, Russia) and in mountains around Kosh-Agach (Altai Republic, Russia), respectively. After fledging, Black Kites from both subpopulations stayed in a small, non-overlapping areas and then migrated to southern Asia through narrow corridors. Black Kites originating from Biysk migrated through the Western Circum-Himalayan Corridor. Black Kites originating from Kosh-Agach used the Trans-Himalayan Corridor crossing the Himalayas in altitudes of up to 6256 m asl. The average total distance travelled of Black Kites from both subpopulations was 9166 km without any significant differences between these subpopulations. Timing of both spring and autumn migration did not vary along different age groups. Black Kites from both subpopulations wintered in low elevations of Pakistan and India. Birds wintered on average for 190 days, and the mean area of individual home ranges in winter was 4704 km2. During the breeding period, birds dwelled in south-western Siberia, where they spent on average 125 days with an average home range size 3537 km2. We found that ontogenetic shifts in migratory behaviour of Black Kites from Eastern Russia differ from those in population/subspecies in Europe. Black Kites crossing the Himalayas fly and, moreover, stay for hours resting at night in the environment of mountains at altitudes over 5000 m.

Autumn migration of black‐necked crane (Grus nigricollis) on the Qinghai‐Tibetan and Yunnan‐Guizhou plateaus

“…The species demonstrated dispersed breeding and concentrated wintering behaviors (Archibald et al, 2020), such that the breeding colonies were scattered around their wintering areas, resulting in diverse migration orientations towards their wintering area (e.g., MYTR). Additionally, black‐necked cranes, being highly dependent on highland wetland ecosystems, could better tolerate the extreme wintering conditions in the highlands compared to other migratory birds crossing the Himalayas (Bishop et al, 2015; Li et al, 2020; Literák et al, 2022; Mi et al, 2022).…”

“…At present, high-altitude migration studies focuses more on famous migration patterns such as the trans-Himalayas (Bishop et al, 2015;Li et al, 2020;Literák et al, 2022;Mi et al, 2022), but studies on the migration patterns of endemic migratory birds on the Qinghai-Tibetan Plateau are scarce.…”

“…Over time, migratory birds on the plateau have developed unique migration patterns to adapt to this environment (Natarajan et al, 2018; Pan et al, 2017; Parr et al, 2019; Qu et al, 2013). At present, high‐altitude migration studies focuses more on famous migration patterns such as the trans‐Himalayas (Bishop et al, 2015; Li et al, 2020; Literák et al, 2022; Mi et al, 2022), but studies on the migration patterns of endemic migratory birds on the Qinghai‐Tibetan Plateau are scarce.…”

Soaring over open waters: horizontal winds provide lift to soaring migrants in weak thermal conditions

“…Wind is an important environmental factor affecting birds’ migratory route selection and overall performance during migration and barrier crossings [ 1 – 4 ]. Especially for soaring birds, the ability to benefit from variable airflow dynamics is crucial due to the higher energetic costs of powered flight [ 5 ].…”

“…Moreover, the occurrence of thermals that can provide energy-free lifts is considered to be relatively low at sea [ 12 ]. In recent studies, the temperature difference between surface and air (∆T) has been used as a proxy for the occurrence of thermals [ 1 , 13 ]. Positive ΔT values correspond to a warmer surface than the air temperature, where a warmer surface heats the air that is pushed up by colder and denser air, creating an uplift.…”