Put two 1/1 white Bird creature tokens with flying onto the battlefield.
Flashback - Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)
Threshold - Put three cards from your graveyard on the bottom of your library: Battlefield Scrounger gets +3/+3 until end of turn. Activate this ability only once each turn, and only if seven or more cards are in your graveyard.