Here a cage was torn open as if some monstrous bird had hatched from it.
Both monstrous birds crashed against the side of the pinnacle-like peak.
The children peered out the windows at the monstrous bird.
The trees all around poured the monstrous birds down on them.
Tristan ducked as one monstrous bird flew over his head.
We don't see any right now, but there's also the big blue heron, a monstrous bird in comparison with the others.
(That monstrous bird in particular is not something you would want to be left alone with for long.)
Back among the trees there was a great, curved shell, bright red, like the egg of some monstrous bird.
The shadows rose from it like a flock of monstrous birds.
Yet the same, or another like to it, a flying darkness in the shape of a monstrous bird.