Calleva Atrebatum is certainly worth a short trip, perhaps a longer one if interested in the subject - the entire circuit of the walls still exists, if in varying degrees of crumbling, and the amphitheatre is very atmospheric. It’s also free to park and go round. I’d perhaps not recommend it for younger children - no facilities, shop, play area or anything like that, and they could easily fling themselves off the walls - I’m not sure I spotted any safety railings at all, and the paths are more flint strewn tracks. The Calleva Arms in nearby Silchester will do you a pint and a nice meal.

As to bird life in mid November - pretty disappointing, apart from the above delight!