Murmuration is a rare Enchantment card from Bloomburrow Commander (BLC), collector number 46. Current market price: $1.93, TCGplayer market prices via Scryfall.
Birds you control get +1/+1 and have vigilance. At the beginning of your end step, for each spell you've cast this turn, create a 1/2 blue Bird creature token with flying named Storm Crow.