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Re: Evidence for bat predation on birds
> Very interesting.... to balance matters, at least one
> tropical eagle species routinely preys on the
> outpouring of bats exiting their caves at twilight, as
> seen on one episode of "Planet Earth".
> --- Guy Leahy <firstname.lastname@example.org> wrote:
Yes indeed. In fact, quite a number of birds of prey feed on bats. Falcons
(including peregrines, merlins, and hobbies) do so regularly, as do some owls.
I would imagine that accipiters would take bats at dusk, as well, though I
cannot recall if this has been officially reported.
There have been some published manuscripts that argue for a substantial
raptorial influence on chiropteran evolution (especially with regard to the
evolution of nocturnality). Fairly recently, Speakman (2001) suggested that
bats were ancestrally diurnal, and driven to nocturnality by the evolution of
raptorial birds. I am not entirely convinced of this hypothesis myself, but it
is notable that Speakman sees raptorial birds as so well equipped to hunt bats
that the entire early chiropteran lineage may have been selected for a
photocycle change. Speakman (2001) is not the first suggestion of its kind,
either. Baker (1962) and Neuweiler (1984) both addressed the importance of
avian predation on bats, as did Fenton et al. (1994).
Baker JK. 1962. The manner and efficiency of raptor depredations on bats.
Condor 64: 500-504
Fenton MB, Reutenbach IL, Smith SE, Swanepoel CM, Grosell J, and Vanjaarsveld
J. 1994. Raptors and bats - threats and opportunities. Animal Behavior 48: 9-18
Neuweiler G. 1984. Foraging, echolocation and audition in bats.
Naturwissenschaften 71: 446-455
Speakman JR. 2001. The evolution of flight and echolocation in bats: another
leap in the dark. Mammal Review. 31: 111-130