Azorius Keyrune

{T}: Add {W} or {U}.
{W}{U}: Azorius Keyrune becomes a 2/2 white and blue Bird artifact creature with flying until end of turn.

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Migratory Route

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.)

Thunderclap Wyvern

Flash (You may cast this spell any time you could cast an instant.)
Flying
Other creatures you control with flying get +1/+1.

Seaside Haven

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

Kangee, Aerie Keeper

Kicker {X}{2} (You may pay an additional {X}{2} as you cast this spell.)
Flying
When Kangee, Aerie Keeper enters, if it was kicked, put X feather counters on it.
Other Bird creatures get +1/+1 for each feather counter on Kangee, Aerie Keeper.

Pride of the Clouds

Flying
Pride of the Clouds gets +1/+1 for each other creature on the battlefield with flying.
Forecast — {2}{W}{U}, Reveal Pride of the Clouds from your hand: Create a 1/1 white and blue Bird creature token with flying. (Activate only during your upkeep and only once each turn.)

Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

Celestial Gatekeeper

Flying
When Celestial Gatekeeper dies, exile it, then return up to two target Bird and/or Cleric permanent cards from your graveyard to the battlefield.

Soraya the Falconer

Bird creatures get +1/+1.
{1}{W}: Target Bird creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Serra Aviary

Tide Skimmer

Flying
Whenever you attack with two or more creatures with flying, draw a card.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Gravitational Shift

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.

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.

Eyes in the Skies

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.)

Island

Jubilant Skybonder

Flying
Creatures you control with flying have "Spells your opponents cast that target this creature cost {2} more to cast."

Serra the Benevolent

+2: Creatures you control with flying get +1/+1 until end of turn.
−3: Create a 4/4 white Angel creature token with flying and vigilance.
−6: You get an emblem with "If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead."

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Ordered Migration

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

Seller of Songbirds

When Seller of Songbirds enters, create a 1/1 white Bird creature token with flying.

Soul of Migration

Flying
When Soul of Migration enters, create two 1/1 white Bird creature tokens with flying.
Evoke {3}{W} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Siani, Eye of the Storm

Flying
Whenever Siani, Eye of the Storm attacks, scry X, where X is the number of attacking creatures with flying.
Partner (You can have two commanders if both have partner.)

Keeper of the Nine Gales

Flying
{T}, Tap two untapped Birds you control: Return target permanent to its owner's hand.

Kangee, Sky Warden

Flying, vigilance
Whenever Kangee, Sky Warden attacks, attacking creatures with flying get +2/+0 until end of turn.
Whenever Kangee blocks, blocking creatures with flying get +0/+2 until end of turn.

Plains

Spirit of the Spires

Flying
Other creatures you control with flying get +0/+1.

Scour the Desert

Exile target creature card from your graveyard. Create X 1/1 white Bird creature tokens with flying, where X is the exiled card's toughness.

Emeria Angel

Flying
Landfall — Whenever a land you control enters, you may create a 1/1 white Bird creature token with flying.

Inniaz, the Gale Force

Flying
{2}{W/U}: Attacking creatures with flying get +1/+1 until end of turn. ({W/U} can be paid with either {W} or {U}.)
Whenever three or more creatures you control with flying attack, each player gains control of a nonland permanent of your choice controlled by the player to their right.

Airborne Aid

Draw a card for each Bird on the battlefield.

Crookclaw Elder

Flying
Tap two untapped Birds you control: Draw a card.
Tap two untapped Wizards you control: Target creature gains flying until end of turn.

Rise of Eagles

Create two 2/2 blue Bird enchantment creature tokens with flying. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Wingmate Roc

Flying
Raid — When Wingmate Roc enters, if you attacked this turn, create a 3/4 white Bird creature token with flying.
Whenever Wingmate Roc attacks, you gain 1 life for each attacking creature.

Windstorm Drake

Flying
Other creatures you control with flying get +1/+0.

Falconer Adept

Whenever Falconer Adept attacks, create a 1/1 white Bird creature token with flying that's tapped and attacking.

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Steel-Plume Marshal

Flying
Whenever Steel-Plume Marshal attacks, other attacking creatures you control with flying get +2/+2 until end of turn.

Murmuring Mystic

Whenever you cast an instant or sorcery spell, create a 1/1 blue Bird Illusion creature token with flying.

Ominous Roost

When Ominous Roost enters and whenever you cast a spell from your graveyard, create a 1/1 blue Bird creature token with flying and "This creature can block only creatures with flying."

Aven Brigadier

Flying
Other Bird creatures get +1/+1.
Other Soldier creatures get +1/+1.

Sprite Noble

Flying
Other creatures you control with flying get +0/+1.
{T}: Other creatures you control with flying get +1/+0 until end of turn.

Alrund's Epiphany

Create two 1/1 blue Bird creature tokens with flying. Take an extra turn after this one. Exile Alrund's Epiphany.
Foretell {4}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Kangee's Lieutenant

Flying
Whenever Kangee's Lieutenant attacks, attacking creatures with flying get +1/+1 until end of turn.
Encore {5}{W} ({5}{W}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Battle Screech

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.)

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Favorable Winds

Creatures you control with flying get +1/+1.

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Mu Yanling, Celestial Wind

+1: Until your next turn, up to one target creature gets -5/-0.
−3: Return up to two target creatures to their owners' hands.
−7: Creatures you control with flying get +5/+5 until end of turn.

Rally of Wings

Untap all creatures you control. Creatures you control with flying get +2/+2 until end of turn.