Bat Hawk: Predator of bats
Posted by BESG on 4 October 07, Thursday
Contributed by YC
The Bat Hawk (Macheiramphus alcinus) is a raptor found in the sub-Saharan Africa, Madagascar, Malay Peninsular, Sumatra, Banka, Borneo, Sulawesi and New Guinea. The bird is a rare visitor to Singapore.
This is a fairly large black hawk with a distinct crest (left). It is often not noticed because it is active only at night. During the day it perches quietly, almost horizontally on the branch of a tall tree, seldom leaving, even for a short while. It becomes active at dusk when it goes on the lookout for small bats, swifts, swallows and large insects.
Prey is caught using the hawk’s talons, usually after a high-speed chase, and transferred to the mouth to be swallowed whole while still in the air. As the period available for hunting is short - at dusk until darkness descends and a short period in the early morning – it needs to hunt where prey is plentiful, like at a cave entrance.
The image below, taken by Wilson Yang, clearly shows one Bat Hawk with a few others among the stream of bats emerging from their roost, probably a cave, in Borneo.
Observations made near a cave in Zambia record a foraging Bat Hawk catching, on an average, seven insectivorous bats during six consecutive nights (Black et al., 1979). As the bats flew out of the cave, the hawk intercepted them and either struck. caught or failed to make contact. The feeding bouts lasted 18.3 minutes per night and the success rate was 49%. The time between killing and swallowing of each bat (average weight 56.3 g) was 6.0 seconds.
Another specialist bat predator is the African Harrier-hawk (Polyboroides typus). There are also a number of owls, goshawks, peregrines and kestrels that occasionally catch bats.
Raptors predating on bats are better known than birds predated by bats. However, there have been recent accounts of giant bats snatching birds from the night sky (1, 2).
Image of hawk courtesy of Lim Kim Chye and Yian, that of bats by Wilson Yang. Check out Wilson’s Flickr site.
References:
1. Altringham, J.D. (1996). Bats: Biology and behaviour. Oxford: University Press.
2. Black, H.L., Howard, G. & Stjernstedt, R. (1979). Observations on the feeding behavior of the Bat Hawk (Macheiramphus alcinus). Biotropica 11(1):18-21.
3. Fenton, M. B., Cumming, D. H. M. & Oxley, D. J. (1977). Prey of Bat Hawks and availability of bats. The Condor, 9:495-497.
4. Madoc, G. C. (1956). An introduction to Malayan birds. Malayan Nature Society, Kuala Lumpur. (revised ed.)
5. Richarz, K. & Limbrunner, A. (1993). The world of bats, the flying goblins of the night. T.F.H. Pub., Inc.
6. Wells, D.R. (1999). The birds of the Thai-Malay Peninsular. Vol. I, Non-passerines. Academic Press, London.
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Categories: Feeding-vertebrates, Raptors
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