The way we caught the birds in the DLC is the way almost every Pokémon should be caught in PLA. They all should have unique mechanics/quest. Like Wimpod running away in SM or Falinks running into holes.

Chimchar for example should be able to climb trees in order to escape and the player must follow. Bird Pokémon should be able to fly up in the air if startled and can only be brought down via bait or only caught if the player is stealthy enough. Water Pokémon should be able to dive and the player follow them. Diglett should be able to dig underground and disappear. Etc.

Since PLA will no doubt have a reduced dex there's no excuse not to make every Pokémon unique in its capture