Ooops, My bad. I guess I'm used to hearing crazy stuff coming from the Dino-Asteroid people I didn't even question it when I read it wrong.
Some owls burrow. Other birds live in caves.
Owls weren't around until the Miocene
But what about Parrots?
Also if the all terriestial birds were wiped out leaving just the cave dwelling birds to later evolve and fill the non-cave niches of modern birds why didn't more bats also diversify into the non-cave niches since they were "Open"?
It is a lot easier for small animals (birds, mammals, lizards, etc.) to find themselves in sheltered and protected areas during firestorms and other such than it would be for multi-tonne critters. I can see birds surviving just by being in fortuitous and unexposed areas.