It's because Mage is essentially easier to kill at level 56.
Remember that bird was pretty OP during Sewer Cap.
And the huge thing is,
MAGE DOES NOT DODGE AT 56!!!!!!
OMG!

With bird, all you have to do is manage to dodge one or two times from mage's skills, or be able to kill fast enough.
A critical arrow hits around 150-300 on a Glyph Mage, a non-critical hits somewhere from 40-170.
I have been able to beat Glyph mages with my bird in Sewer Gear as well.
In the end, it all comes down to luck, since Dodge is pure luck.