The air stored inside the rachises of Decidueye's feathers insulates the Pokémon against Hisui's extreme cold. This is firm proof that evolution can be influenced by environment.
Decidueye is a Grass/Ghost-type Pokémon. It takes double damage from Fire, Ice, Flying, Ghost and Dark, resists Water, Electric, Grass and Ground, and is immune to Normal and Fighting. Its base stats add up to 530: the highest is Attack (107) and the lowest is Speed (70).
It is the third stage of its evolution line, along with Rowlet and Dartrix. Its ability is Overgrow, and its Hidden Ability is Long Reach. It is in the Flying egg group and can breed with 74 species. In Scarlet and Violet it learns 19 moves by level-up and 71 by TM. Its Hisuian Decidueye form has its own page.
FORMS WITH THEIR OWN PAGE
BASE STATS
ABILITIES
Powers up Grass-type moves when the Pokémon's HP is low.
The Pokémon uses its moves without making contact with the target.