Newly discovered threat to migrating birds

[aeshna5]

In an article I've just received from Birdguides is the discovery of a newly discovered danger to nocturnal migrating birds in Europe. It comes in the form of a flying mammal- the scarce Giant Noctule Bat, Nyctalus lasiopterus, whch is found around the mediterranean basin, particularly around major migration hotspots.

Feathers had been found in the faeces of this species, though some scientists argued that this wasn't proof that the bats had preyed on migrating birds. Then a team of Spanish scientists did some isotope studies which did demonsrate seasonal predation, with birds been taken in spring + autumn, with insects dominating in summer. Birds were a more important food item in the autumn than spring, as many more + inexperienced juveniles would be flying.

Some tropical species are known to take frogs + other small vertebrates, but this discovery was unexpected. Fascinating stuff!

[Wild-Woman]

Originally Posted by aeshna5

In an article I've just received from Birdguides is the discovery of a newly discovered danger to nocturnal migrating birds in Europe. It comes in the form of a flying mammal- the scarce Giant Noctule Bat, Nyctalus lasiopterus, whch is found around the mediterranean basin, particularly around major migration hotspots.

Feathers had been found in the faeces of this species, though some scientists argued that this wasn't proof that the bats had preyed on migrating birds. Then a team of Spanish scientists did some isotope studies which did demonsrate seasonal predation, with birds been taken in spring + autumn, with insects dominating in summer. Birds were a more important food item in the autumn than spring, as many more + inexperienced juveniles would be flying.

Some tropical species are known to take frogs + other small vertebrates, but this discovery was unexpected. Fascinating stuff!

I would imagine that this is normal predation and so hopefully wouldn't upset the migratory balance??

[Blackdog]

There is another piece published here: Google Image Result for http://www.swissinfo.org/xobix_media/images/sri/2007/sriimg20070214_7527043_0.jpg

You would certainly see these flying around at twighlight! 747 Jumbo bats

[henrya]

Originally Posted by Wild-Woman

I would imagine that this is normal predation and so hopefully wouldn't upset the migratory balance??

Greater Noctules are quite rare - the chances of them affecting bird populations are pretty close to zero!

henrya

[badgerwatcher]

How extraordinary. I've never heard of these. So are we talking about rat or squirrel size?
Surely they would be at risk of their wings being torn by birds claws?

[henrya]

Originally Posted by badgerwatcher

How extraordinary. I've never heard of these. So are we talking about rat or squirrel size?
Surely they would be at risk of their wings being torn by birds claws?

They are not a British species, and pretty rare in Europe, so it's not surprising few have heard of them. Maybe small rat size. One of the links seemed to imply that they caught birds in flight - I'm not sure if this has been observed. The earlier paper said the droppings containing feather remains had been found in bat (or bird) boxes so perhaps they grab roosting birds? I think the next stage of the research is to find exactly how the bats catch and eat the birds.

henrya

[aeshna5]

Originally Posted by Wild-Woman

I would imagine that this is normal predation and so hopefully wouldn't upset the migratory balance??

Yes it would be normal predation + as these bats are pretty rare, effect on population would be close to zero; but it's the fact we've only recently become aware of this.