As you can see, most of the Mages' Guild's guards can actually do some magic themselves ... that's probably not too surprising.
The Guild's guard isn't just made up of mages who want to protect their friends, though. Some are just normal people doing a guard job, sometimes friends or family of guild members, sometimes just mercenaries who were looking for work. Take a look at Thomas for example, the human male on the left in the last panel - he can't do magic for shit and is thus only relying on his sword. But even the ones who can do magic have to spend a lot of time on their guard duties and physical training and don't have that much of it left to work on their magic skills. In the end most of them make do with some basic telekinesis in combat, much less than what someone like Katharina could do (once she manages to shake off that paralizing fear of being killed).
So you end up with a lot of differend levels of magic ability in your troups, more than in most other armies. Their battle strategies have to be planned accordingly. The group here is lead by Lt. Kemyran Kari Gren Tshe, the Drak lady talking to Katharina in panel 2. She seems to already have a good fighting plan how to deal with those big bad birds ...
... let's see how well it holds up, shall we?