Tranquil can have one of two Abilities: Big Pecks, which prevents its Defense from being lowered by moves such as Tail Whip or Screech, or Super Luck, which raises the Critical Hit Ratio of moves, and can also be used simultaneously with Focus Energy and Dire Hit, but is cancelled out by Shell Armor or Lucky Chant.
A third Ability is avalable to Tranquill that come from the Dream World, the Rivalry Ability. This Ability increases its Attack if the foe is of the same gender, but its Attack will decrease if the foe is a Pokémon of the opposite gender.
Tranquill is in the Flying Egg Group, and its Egg takes approximately 3,840 Steps to hatch. It takes Tranquill 1,059,860 Experience Points to reach Level 100.
Tranquill takes on the appearance of a mid-sized pigeon with a differing color scheme when compared to the form that it evolved from. The pink coloring by its beak has now formed a partial mask around its eyes.
Tranquill doesn't have any distinguished features that differentiate between male or female.
Tranquill appears at Route 12, Pinwheel Forest, Lostlorn Forest regardless of the season, and at Routes 6 & 7 and Dragonspiral Tower during the Spring, Summer, and Autumn months in Black and White. In Black 2 and White 2, Tranquill appears at Routes 3, 6, 7, 12, and Victory Road at all times of the year, and at Dragonspiral Tower during every season except Winter.
Tranquill appears at the Cove Area in Cove Town in PokéPark 2: Wonders Beyond. It can be befriended by beating it in a Tag Race.
Trading Card Game
Tranquill is listed as an Uncommon Card in the Black&White and the Emerging Powers sets.
Ash's rival Trip would use a Tranquil in a battle against Ash. It would easily defeat Oshawott and Tepig before being beaten by Pikachu. Trip would also use his Tranquill in the episode A Venipede Stampede.
Ash's Tranquill would appear in both versions of Pokémon Movie 14.
Tranquill's Manga Information is unknown as of writing.
Tranquill is listed in the NFE, or Not Fully Evolved Tier of Competitive Battling as it hasn't reached its final evolved form.
Via Move Tutor (Black2/White2)