Whenever a Bird is put into your graveyard from the battlefield, put a feather counter on Soulcatchers' Aerie. Bird creatures get +1/+1 for each feather counter on Soulcatchers' Aerie.
Near Mint - $0.40
Lightly Played - $0.30
Moderately Played - $0.30
Heavily Played - $0.20
Damaged - $0.20
Near Mint Spanish - $0.40
Lightly Played Spanish - $0.30
Moderately Played Spanish - $0.30
Heavily Played Spanish - $0.20
Damaged Spanish - $0.20