[Agema]

It's been about a year since I last did it and it may have changed in a patch, but last time I used it those hawks were excellent siege *defenders*. It's very satisfying when you're in a pinch to buy time tying down a large enemy army for an extended siege.

When your army is on the outside, you should think about draconians. Just leave the Chief recruiting, and shunt the draconian grunts onto other commanders (ideally a flyer) to ferry where they are needed. They've got about 18Str, so they're worth about 4 each for sieging. If you think it's necessary they can also help storm the castle and make life difficult for the defenders. Although they'll probably take casualties, and that somewhat defeats the purpose of building up a substantial number to take walls down quickly.

Having said that, even cheaper would probably be that wallshaker horn.