Mammals do not have diversity interms of flying species...

[AstusAleator]

1st - as someone has already stated (yet I'm entirely not against re-stating) there is an amazing diversity of bats. Bats are incredible, period.

2nd - I wonder if there was a time when flying bugs preyed on birds...? That would be SWEET.

[MrMistery]

Astus, remember there is a tarantula that is documented to prey on chickens. It would be no surprise to me if some big bugs collectively hunt birds nowadays...

[AstusAleator]

Very good point. I'm just envisioning a huge flying insect swooping down and snatching a flying bird out of the air... kind of a reverse of what normally happens.

[MichaelXY]

Astus, remember there is a tarantula that is documented to prey on chickens. It would be no surprise to me if some big bugs collectively hunt birds nowadays...

I had to read it for myself. Holy Crawly...
http://www.blueplanetbiomes.org/goliath ... spider.htm

[MrMistery]

Also remember Japan has the Japanese giant hornet, that reaches 17 centimeters in size. In canada i saw fireflies that reached similar sizes. I am not saying an insect could necessarily take a bird 1:1, but insects usually find power in numbers, so why not hunt birds like that?