Soulcatchers' Aerie 
Enchantment
Whenever a Bird is put into your graveyard from the battlefield, put a feather counter on this enchantment. Bird creatures get +1/+1 for each feather counter on this enchantment.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL