You need 55th lvl and evolve it on "Improved kookaburra".
If you wanna level it fast, you need same level as kooka.
Just make new nuker, take it on 25th lvl and until you hit 52 on nuker, she will have 55th level.
Hmm, holy fuck lvl 55 we need 1 month for up this xD Actually kooka take 0,30-0,40% exp each mob, is more fast if i create new char just for up pet?
Cause if i need make all class quest again, i think we need alot of days just for lvl kooka :/
Thanks and sorry for me english