Clockwork Avian is a uncommon Artifact Creature — Bird card from Masters Edition IV (ME4), collector number 190.
Flying This creature enters with four +1/+0 counters on it. At end of combat, if this creature attacked or blocked this combat, remove a +1/+0 counter from it. {X}, {T}: Put up to X +1/+0 counters on this creature. This ability can't cause the total number of +1/+0 counters on this creature to be greater than four. Activate only during your upkeep.