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Flock of Chinese Sparrowhawks (Accipiter soloensis) |
The migration of raptors in the East Asian Continental and Oceanic Flyways has been little studied. These flyways are huge and stretch across more than 80 degrees of latitude from northeast Siberia to eastern Indonesia and New Guinea. With hundreds of thousands of raptors migrating along this route, the latter is the world’s major oceanic raptor migration system, and it remains one of the least understood in the world.
At the southern end of the flyways within the vast Indonesian Archipelago, a system of island corridors leads to the heart of the zoogeographic subregion of Wallacea, which is believed to be the main wintering ground for several species of raptors from the eastern Palearctic. Because virtually no studies on raptor migration have been carried out in Wallacea, Natural Research (UK) and Hawk Mountain Sanctuary (USA) are supporting a pilot study on the remote Indonesian island of Sangihe.
 Sangihe is strategically located along a chain of “stepping-stone” islands between Mindanao (Philippines) and Sulawesi (Indonesia), and we suspected it to be a major concentration and passage point to the presumed wintering areas of Wallacea.
Our team made two full season counts, totalling over four months of field effort. In autumn only we recorded more than 230,000 migratory raptors of the following species: Osprey Pandion haliaetus, Grey-faced Buzzard Butastur indicus, Chinese Sparrowhawk Accipiter soloensis, Japanese Sparrowhawk A. gularis, Harriers Circus sp., and Peregrine Falcon Falco peregrinus calidus. Chinese Sparrowhawk comprised approximately 98% of the flight.
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Adult female Chinese Sparrowhawk |
We estimate that at least 400,000 raptors are streaming into Wallacea each autumn from the Continental and Oceanic Flyways combined. The raptor migration into the relatively small land area of eastern Indonesia has been unappreciated. Furthermore, the scarcity of winter records throughout Wallacea suggests either that observer coverage in the region is still very poor, or that a large proportion of the migrants are dispersing into remote and poorly surveyed areas possibly as far as New Guinea, or both. Keep an eye out for our results in peer-reviewed journals where we hope to publish the full details of this important raptor migration.
For further information, please contact Francesco Germi: Francesco@germi.freeserve.co.uk
Photographs copyright: F. Germi
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