Cheers for the replies so far and I've just realized something:
A creature of an older world maybe it was, whose kind, lingering in forgotten mountains cold beneath the Moon, outstayed their day, and in hideous eyrie bred this last untimely brood, apt to evil.
In hideous eyrie.. Doesn't that mean a 'hideous eagle nest' ? So maybe they were cross breeds of some ancient creature, like the Bats and the Eagles, and were probably based on pterodactyls as Son of Numenor(Ace avatar btw) said!
Pretty cool eh!!
Dwimmerlaik