From the Malifaux Tactica Wiki:
He's a guy with a bird. How scary can that be? The answer, apparently, is "very scary." With a very long range and the ability to ignore Line of Sight, the Austringer has quickly become a premier Guild Minion.
The Austringer has an average 4" Walk, cannot Charge and beyond Quick Retreat (see below), has no other way of enhancing his own mobility. Fortunately, after the Austringer finds a nice piece of terrain to hide in, his long reach means he'll rarely needs to move anyway.
The Austringer is armed with a Raptor - a Range 12 weapon that ignores cover modifiers and Line of Sight. This means you can sit behind a huge piece of blocking terrain and still attack up to 12" away, ignoring any negative flips from cover that your opponent is trying to use to avoid getting hit.
The Austringer has little direct synergy with any one Master. The closest is Lucius (a Henchman), but in any case, he still makes for a good choice in your average Guild crew, regardless of who's leading.