Deck History
I began developing the idea of a mono-flying deck after the release of Mirrodin. It wasn't very good, but back then the options were more limited and I hadn't developed much as a brewer. As I grew, so did the deck, but the focus didn't change: play flying creatures and deal 20 damage in the air.
At some point, I began to exclude the flying kor and leonin and chose to focus on birds. For a while I went pretty deep on the bird flavor (Mmm) to the point where every card had to feature a bird in the art, text, or function. These lists were grindy and control-oriented, often playing around with Stormscape Familiar and Squadron Hawk synergy and the interaction between Supreme Verdict and Soulcatchers' Aerie was the main wincon. Probably my greatest achievement was making Seaside Haven seem OK, but over time I ditched the control gameplan and returned to the much more effective beatdown strategy.
When Shadows over Innistrad released, the new spirits were so powerful that I couldn't ignore them. After much deliberation I ditched the birds theme and dove into the spirits tribe. This has made the deck much more naturally disruptive, and the loss in explosive daamge potential gave way to the ability to protect my board. No longer could one or two well timed removal spells ruin my day.
This latest iteration of the deck is probably another Mausoleum Wanderer printing (a.k.a. another 1-drop flying spirit with upside) away from being very good, but I am confident that this list has game against many Modern decks.
Strategy
This is a zoo deck, plain and simple, and that means the plan is to deal 20 damage as quickly as possible. An ideal curve might be turn one Cloudfin Raptor, turn two Mausoleum Wanderer and attack for one, turn three Selfless Spirit and attack for four, turn four Pride of the Clouds and attack for six, then turn 5 attack for eleven, a total of 21 damage. There is plenty of redundancy on these effects and most games end before turn 6 if not disrupted.
Against some strategies, certain cards are necessary to protect the creature-centric beatdown plan. When playing against control decks and other decks with plenty of removal, Judge's Familiar, Selfless Spirit, and Rattlechains protect our creatures until they can finish the opponent off. Against combo decks, Spell Queller becomes the best card in the deck. As for aggro decks, the plan is to block their creatures while flying over the top, sometimes you can be faster than them as well.
As you've probably noticed, there are no instants or sorceries in the mainboard. This deck is based on the Philosphy of Fire, and a first turn Cloudfin Raptor on average deals more damage than a single Lightning Bolt could, or it demands a response from the opponent. Sure, the ability to bolt a bird (y'know, besides ours) would add some play to the deck, but the creatures are almost all spells themselves. From Siren Stormtamer to Spell Queller, many of the creatures function as spells that also benefit Pride of the Clouds and Favorable Winds.
It's strange to see a U/W zoo deck, especially one that doesn't play to the strengths of blue (ie. counterspells and tempo), but the creatures here are so efficient and come equipped with effects that disrupt interaction, it works surprisingly well.
Card Choices
Cloudfin Raptor - This is quietly one of the best creatures in the deck.
Judge's Familiar -
Siren Stormtamer -
Rattlechains -
Selfless Spirit -
Pride of the Clouds - Here's our Tarmogoyf. It's not unusual to play this as a 5/5. He always evolves Cloudfin Raptor, and multiples can be used to forecast (albeit rarely). When it comes to closing out games quickly, nothing else in the deck comes close. It's just a shame this is a cat, not a bird.
Drogskol Captain -
Favorable Winds - When this deck first began years and years ago, Glorious Anthem was in it. Although I removed it quickly, the enchantment was almost good. One of my first Modern decks was B/W Tokens and that taught me the power of the 2-CMC anthem. Of course, there you also played Lingering Souls and Raise the Alarm, but hey, forget that. This card is really good.
The Sideboard
I know there are no bird cards in the sideboard, it's just something I've had to accept. Sure, I tried to make a sideboard of bird cards, but at some point, after I added the third Keeper of the Nine Gales (because otherwise birds have no way to interact with artifacts), Aven Riftwatcher (because I lost to burn every time), and the forth Morningtide (which is only a bird card because the flavor text quotes one), I just gave up.
