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Re: Long, long last gasp. (fwd)



Gautam Majumdar wrote:

> Its not all one way traffic. Some bats also prey on birds.

Indeed - Australian ghost bats occasionally catch small birds as well
(as well as small mammals, including other bats).

Jonh Bois wrote:

>> Of course, flying foxes throw a spanner in the works. They often fly
>> about during the day.

> ...but are primarily nocturnal, right?

Actually they tend to be more crepuscular. I suspect even their eyesight
is not good enough to navigate on really dark nights (ie. overcast with
no moon). Visit a colony during the day and you are almost deafened by
the cacophany. You will always see many animals in flight no matter what
time of the day you visit them.

> One could imagine that flying foxes can assess predator density and become
> more relaxed about this where few predators are about--e.g., the suburbs
> of Q'land cities.

Even wild colonies are quite active during the day - especially since
they must avoid predators like raptors and pythons while they roost.
During the breeding season they have been known to form huge
super-colonies of several million strong (something that tests both the
eardrum and nose of any researcher). Fishing eagles and pythons hardly
make a dent in such numbers though.

They don't just exist in tropical or sub-tropical areas either. Both
Sydney and Melbourne have sizable and permanent populations. In fact
they are so numerous in Melbourne that attempts are being made to
relocate them before they cause too much damage to the Royal Botanic
Gardens (they have a similar problem in Sydney). Every autumn when my
fig tree is in fruit I get visited by huge black shapes in the night - a
few will feed from the tree while several circle the neighbourbood in a
holding pattern waiting for their turn. You don't reaalise how big these
animals are until you've had one fly over your head almost low enough to
touch - a wingspan of a metre or more in some animals.

David Marjanovic wrote:

>> Of course, flying foxes also have incredible eyesight...

> Details please?

Details? Well, they have huge protruding eyes, no echolocation, and
manage to fly about in low-light conditions without plowing into things.
I'm guessing their eyes are better in low-light conditions than mine -
therefore better than most microbats. Do Google search with 'flying fox
eyesight' and you'll get all sorts of results (even some that aren't
anecdotal!).

-- 
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Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
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