What could be in the towers? Sure there are two Houses roomed in them, but there are a lot more towers!
I think that there would be, somewhere in one of the towers, an aviary. A large, spacious place kept magically heated, where birds of all kinds (even owls) could stay and live and thrive. This aviary could house what some would call 'mundane' (but I feel that all birds are rather magical) as well as many of the more magical species. This room would be a sanctuary for birds who are unable to live in the wild, for various reasons such as muggle 'household pets' let out into the wild in a climate totally unsuitable for them and they'd die within a few days or for damage to their body (or their mate is damaged and they have chosen to stay with their mate). A sanctuary for birds who, if they heal, and so choose, can be taken to a place of their choice and let loose.
The birds who eat smaller birds, though, would be told strictly they may not eat their neighbors.