Saw a tv documentary a number of years ago that showed birds doing aeros, aparently just for the fun of it.
Also saw a crow do a barrel roll and looking really pissed off afterwards when it got caught in the vortex of a rotating 757.
They certainly fly at night as a late bird of unknown manufacture can vouch after denting my radome at 500ft on the approach.
I reckon that they all do an IR at a very early age otherwise how could they fly in controlled airspace?