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.

Mu Yanling, Sky Dancer

+2: Until your next turn, up to one target creature gets -2/-0 and loses flying.
−3: Create a 4/4 blue Elemental Bird creature token with flying.
−8: You get an emblem with "Islands you control have '{T}: Draw a card.'"

Duskrider Falcon

Zinnia, Valley's Voice

Flying
Zinnia, Valley's Voice gets +X/+0, where X is the number of other creatures you control with base power 1.
Creature spells you cast have offspring {2}. (You may pay an additional {2} as you cast a creature spell. If you do, when that creature enters, create a 1/1 token copy of it.)

Speakeasy Server

Flying
When Speakeasy Server enters, you gain 1 life for each other creature you control.

River Hoopoe

Flying
{3}{G}{U}: You gain 2 life and draw a card.

Love Song of Night and Day

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You and target opponent each draw two cards.
II — Create a 1/1 white Bird creature token with flying.
III — Put a +1/+1 counter on each of up to two target creatures.

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.

Strix Serenade

Counter target artifact, creature, or planeswalker spell. Its controller creates a 2/2 blue Bird creature token with flying.

Nesting Dovehawk

Flying
At the beginning of combat on your turn, populate. (Create a token that's a copy of a creature token you control.)
Whenever a creature token you control enters, put a +1/+1 counter on Nesting Dovehawk.

Salvation Swan

Flash
Flying
Whenever Salvation Swan or another Bird you control enters, exile up to one target creature you control without flying. Return it to the battlefield under its owner's control with a flying counter on it at the beginning of the next end step.

Cloudchaser Eagle

Flying
When Cloudchaser Eagle enters, destroy target enchantment.

Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature you control with flying enters, Watcher of the Spheres gets +1/+1 until end of turn.

Evolving Wilds

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

Owlbear

Trample
Keen Senses — When Owlbear enters, draw a card.

Judge's Familiar

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

Storm Crow

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

Seaside Haven

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

Hunting Moa

Echo {2}{G} (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 Hunting Moa enters or dies, put a +1/+1 counter on target creature.

Carrier Pigeons

Flying
When Carrier Pigeons enters, draw a card at the beginning of the next turn's upkeep.

Whippoorwill

{G}{G}, {T}: Target creature can't be regenerated this turn. Damage that would be dealt to that creature this turn can't be prevented or dealt instead to another permanent or player. When the creature dies this turn, exile the creature.

Raven of Fell Omens

Flying
Whenever you commit a crime, each opponent loses 1 life and you gain 1 life. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

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.)

Supply-Line Cranes

Flying
When Supply-Line Cranes enters, put a +1/+1 counter on target creature.

Derevi, Empyrial Tactician

Flying
When Derevi, Empyrial Tactician enters and whenever a creature you control deals combat damage to a player, you may tap or untap target permanent.
{1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.

Swan Song

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

Dazzling Denial

Counter target spell unless its controller pays {2}. If you control a Bird, counter that spell unless its controller pays {4} instead.

Birds of Paradise

Heron of Hope

Flying
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: Heron of Hope gains lifelink until end of turn.

Monastery Flock

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

The Goose Mother

Flying
The Goose Mother enters with X +1/+1 counters on it.
When The Goose Mother enters, create half X Food tokens, rounded up.
Whenever The Goose Mother attacks, you may sacrifice a Food. If you do, draw a card.

Island

Nimble Larcenist

Flying
When Nimble Larcenist enters, target opponent reveals their hand. You choose an artifact, instant, or sorcery card from it and exile that card.

Welkin Tern

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

Dukhara Peafowl

{U}: Dukhara Peafowl gains flying until end of turn.

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.

Dragonstalker

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters tapped unless you control two or more basic lands.

Shrike Force

Disenchant

Celestial Messenger

Flash (You may cast this card any time you could cast an instant.)
Flying
Celestial Messenger gets +1/+1 as long as you control a Yanling planeswalker.

Aven Gagglemaster

Flying
When Aven Gagglemaster enters, you gain 2 life for each creature you control with flying.

Finch Formation

Offspring {3} (You may pay an additional {3} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Flying
When this creature enters, target creature you control gains flying until end of turn.

Ithilien Kingfisher

Flying
When Ithilien Kingfisher dies, draw a card.

The Raven's Warning

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 1/1 blue Bird creature token with flying. You gain 2 life.
II — Whenever one or more creatures you control with flying deal combat damage to a player this turn, look at that player's hand and draw a card.
III — You may put a card you own from outside the game on top of your library.

Animal Sanctuary

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

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.

Dawnfeather Eagle

Flying
When Dawnfeather Eagle enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Yorion, Sky Nomad

Companion — Your starting deck contains at least twenty cards more than the minimum deck size. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flying
When Yorion enters, exile any number of other nonland permanents you own and control. Return those cards to the battlefield at the beginning of the next end step.

Favorable Winds

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

Eagle of Deliverance

Flying
When Eagle of Deliverance enters, put an indestructible counter on another target creature you control. Draw a card if that creature's power is 2 or less.

Sunbird Effigy

Flying, vigilance, haste
Sunbird Effigy's power and toughness are each equal to the number of colors among the exiled cards used to craft it.
{T}: For each color among the exiled cards used to craft Sunbird Effigy, add one mana of that color.

Sunbird Standard

{T}: Add one mana of any color.
Craft with one or more {5} ({5}, Exile this artifact, Exile one or more other permanents you control and/or cards from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Sunbird Standard // Sunbird Effigy

Shabraz, the Skyshark

Partner with Brallin, Skyshark Rider
Flying
Whenever you draw a card, put a +1/+1 counter on Shabraz, the Skyshark and you gain 1 life.
{W/U}: Target Human gains flying until end of turn.

Dreamtail Heron

Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, draw a card.

Plumecreed Escort

Flash
Flying
When Plumecreed Escort enters, target creature you control gains hexproof until end of turn.

Knightfisher

Flying
Whenever another nontoken Bird you control enters, create a 1/1 blue Fish creature token.

Kykar, Wind's Fury

Flying
Whenever you cast a noncreature spell, create a 1/1 white Spirit creature token with flying.
Sacrifice a Spirit: Add {R}.

Mist Raven

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

Darba

At the beginning of your upkeep, sacrifice Darba unless you pay {G}{G}.

Zodiac Rooster

Plainswalk (This creature can't be blocked as long as defending player controls a Plains.)

Soaring Show-Off

Flying
When Soaring Show-Off enters, each player draws a card.

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.

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Windbrisk Heights enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Plains

Mystic Familiar

Flying
Threshold — As long as seven or more cards are in your graveyard, Mystic Familiar gets +1/+1 and has protection from black.

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

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.)

Battlefield Raptor

Murmuration

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.

Lilypad Village

{T}: Add {C}.
{T}: Add {U}. Spend this mana only to cast a creature spell.
{U}, {T}: Surveil 2. Activate only if a Bird, Frog, Otter, or Rat entered the battlefield under your control this turn.

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Terramorphic Expanse

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

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.)

Clockwork Condor

Flying
Clockwork Condor enters with three +1/+1 counters on it.
Whenever Clockwork Condor attacks or blocks, remove a +1/+1 counter from it at end of combat.

Bird Maiden

Dream Thrush

Flying
{T}: Target land becomes the basic land type of your choice until end of turn.

Resilient Roadrunner

Haste, protection from Coyotes
{3}: Resilient Roadrunner can't be blocked this turn except by creatures with haste.

Sky Crier

Flying, lifelink
{3}{W}: You and target opponent each draw a card.

Gilded Goose

Flying
When Gilded Goose enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Reflections of Littjara

As Reflections of Littjara enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

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.)

Mercurial Kite

Flying
Whenever Mercurial Kite deals combat damage to a creature, tap that creature. That creature doesn't untap during its controller's next untap step.

Beacon Hawk

Flying
Whenever Beacon Hawk deals combat damage to a player, you may untap target creature.
{W}: Beacon Hawk gets +0/+1 until end of turn.

Swans of Bryn Argoll

Flying
If a source would deal damage to Swans of Bryn Argoll, prevent that damage. The source's controller draws cards equal to the damage prevented this way.

Aven Brigadier

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

Souvenir Snatcher

Mutate {5}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, gain control of target noncreature artifact.

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.)

Artificer's Assistant

Flying
Whenever you cast a historic spell, scry 1. (Artifacts, legendaries, and Sagas are historic. To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Kingfisher

Flying
When Kingfisher dies, draw a card.

Lofty Denial

Counter target spell unless its controller pays {1}. If you control a creature with flying, counter that spell unless its controller pays {4} instead.

Thieving Magpie

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Thieving Magpie deals damage to an opponent, draw a card.

Empyrean Eagle

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

Yanling's Harbinger

Flying
When Yanling's Harbinger enters, you may search your library and/or graveyard for a card named Mu Yanling, Celestial Wind, reveal it, and put it into your hand. If you search your library this way, shuffle.

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Wake of Vultures

Flying
{1}{B}, Sacrifice a creature: Regenerate Wake of Vultures.

Liberated Livestock

When Liberated Livestock dies, create a 1/1 white Cat creature token with lifelink, a 1/1 white Bird creature token with flying, and a 2/4 white Ox creature token. For each of those tokens, you may put an Aura card from your hand and/or graveyard onto the battlefield attached to it.

Wing Shards

Target player sacrifices an attacking creature.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Tempest Owl

Kicker {4}{U} (You may pay an additional {4}{U} as you cast this spell.)
Flying
When Tempest Owl enters, if it was kicked, tap up to three target permanents.

Coveted Peacock

Flying
Whenever Coveted Peacock attacks, you may goad target creature defending player controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Pilfering Hawk

Flying
{S}, {T}: Draw a card, then discard a card. ({S} can be paid with one mana from a snow source.)

Commander Eesha

Fire-Omen Crane

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Fire-Omen Crane attacks, it deals 1 damage to target creature an opponent controls.