"Nick Maclaren" wrote in message
...
In article ,
Jaques d'Altrades wrote:
The message
from "Sad Sid" . contains these words:

Every evening I sit out on the patio watching the sun drop below the
horizon. As the sun sets the jackdaws gather in huge flocks of several
hundred birds, diving and swooping together until the sun sets. Often I
see
a bat emerge from the eaves of the Manse to flutter about catching
insects
on the wing.
Last night the bat emerged and flew across my garden. A pair of the
jackdaws
swooped - and suddenly the bat was gone!
I have never seen a jackdaw take live prey like this before - is this
usual
behaviour?

Them jackdaw's rooks.

I'd lay odds on any bat when it comes to ærial maoeuvrability versus a
rook.

Not quite any bat - some of the flying foxes (fruit bats) aren't very
agile. But, in the UK, I agree. My guess would be that the bat just
did a jink, and disappeared from sight - while several birds might
well take bats, it seems a little implausible that they would be able
to catch one on the wing. Unless seriously sick, injured or whatever,
of course.

I have certainly seen bats disappear into thin air many times. While
my reactions are good, those of bats are one hell of a lot better!

And the way that they move conflicts with the 'wiring' of our visual
system to make them very hard to see, in a way that doesn't apply to
land mammals and almost all birds. Our visual system has a fairly
high latency, and makes up for that by extrapolating in all sorts of
complicated ways - this makes it possible to follow some very fast
movement, but means that things that move in other ways can simply
vanish from sight.


Nocturnal migrating passerines have been proven (using radar and also faecal
pellet examination) to fall victim to 'on the wing' predation by the greater
noctule bat, in Spain. Apart from that, I understand such 'conflicts' are
considered rare.