Corvinomancer's Call

MindDelve {4}(You may discard 4 cards and draw
3 card to reduce the cost of this spell by {4}.)
When Corvinomancer's Call comes into play or
you cast a non-creature spell and you chose to
have Corvinomancer's Call counter it, create
three 1/1 black Crow tokens with Flying and
the Bird type
If you used Mind Delve to cast Corvinomancer's
Call, this enchantment gains "Bird Creatures you
control gain Hexproof."