As an additional cost to cast this spell, discard X cards.

Look at target opponent's hand and choose X cards from it. That player discards those cards.

Flying

When Aphetto Vulture dies, you may put target Zombie card from your graveyard on top of your library.

Flying

When Augury Owl enters the battlefield, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Flying

Sacrifice Aven Augur: Return up to two target creatures to their owners' hands. Activate only during your upkeep.

Flying

When Aven Fateshaper enters the battlefield, look at the top four cards of your library, then put them back in any order.

{4}{U}: Look at the top four cards of your library, then put them back in any order.

Flying

When Aven Surveyor enters the battlefield, choose one --

• Put a +1/+1 counter on Aven Surveyor.

• Return target creature to its owner's hand.

Flying, deathtouch

When Baleful Strix enters the battlefield, draw a card.

Create two 1/1 white Bird creature tokens with flying.

Flashback--Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying, vigilance

Flying (This creature can't be blocked except by creatures with flying or reach.)

Carrion Crow enters the battlefield tapped.

Flying

When Crow of Dark Tidings enters the battlefield or dies, mill two cards. (Put the top two cards of your library into your graveyard.)

Flying

When Death's-Head Buzzard dies, all creatures get -1/-1 until end of turn.

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Create a 1/1 white Bird creature token with flying, then populate. (Create a token that's a copy of a creature token you control.)

Create X 1/1 white Bird Soldier creature tokens with flying, where X is the number of attacking creatures.

({T}: Add {G}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Flying

Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Flying

{B}: Regenerate Kathari Remnant.

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

Create four 1/1 white Bird creature tokens with flying.

Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Flying

When Mist Raven enters the battlefield, return target creature to its owner's hand.

Flying

Whenever another creature dies, you may draw a card. If you do, discard a card.

Domain -- Create a 1/1 blue Bird creature token with flying for each basic land type among lands you control.

Flying

When Owl Familiar enters the battlefield, draw a card, then discard a card.

Flying

When Palace Familiar dies, draw a card.

Flying

When Parasitic Strix enters the battlefield, if you control a black permanent, target player loses 2 life and you gain 2 life.

({T}: Add {W}.)

({T}: Add {W}.)

({T}: Add {W}.)

({T}: Add {W}.)

Flying

{1}: Rainbow Crow becomes the color of your choice until end of turn.

Flying

Echo {2}{U} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

When Raven Familiar enters the battlefield, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Target player discards a card.

Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Flying

Rimefeather Owl's power and toughness are each equal to the number of snow permanents on the battlefield.

{1}{S}: Put an ice counter on target permanent.

Permanents with ice counters on them are snow.

Flying (This creature can't be blocked except by creatures with flying or reach.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Flying

When Sage Owl enters the battlefield, look at the top four cards of your library, then put them back in any order.

{T}: Add {C}.

{W}{U}, {T}, Sacrifice a Bird: Draw a card.

Flying

Morph {3}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

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.

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.

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.

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.

Flying

When Spire Owl enters the battlefield, look at the top four cards of your library, then put them back in any order.

Flying (This creature can't be blocked except by creatures with flying or reach.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

Kicker {4}{U} (You may pay an additional {4}{U} as you cast this spell.)

Flying

When Tempest Owl enters the battlefield, if it was kicked, tap up to three target permanents.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Flying

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Flying

Exploit (When this creature enters the battlefield, you may sacrifice a creature.)

When Vulturous Aven exploits a creature, you draw two cards and you lose 2 life.

Flying

Creature spells with flying you cast cost {1} less to cast.