Now with the new team leader images being added to the game, and them giving the option to switch teams, Pokemon Go’s twitter has officially decided to cap on their update and release how exactly the legendary birds will be encountered!
They go on to explain that the leader of your team will tell you about the sighting of the legendary bird Pokemon, later giving you a chance to collect their “Legendary Feathers” However the only way to speak to your leader and deliver the feathers would be to walk toward’s a gym that is owned by your team.
After you collect 3 feathers the legendary bird lands at the gym you delivered your feathers to, initiating a batle that any teammates from your team can actually jump in and help fight. The battle gives candies for the Pokemon used in the fight, so if you use a Scyther you’ll get Scyther candy.
The birds show up at 1500 CP and will not have a way to get candy to ensure they won’t be able to break the game and be unbeatable. ONCE the battle is complete you get one of 3 new Pokeballs called the Team Valor ball , Team Instinct Ball and Team Mystic Ball that give you a 100% catch rate for the Legendary Pokemon you just battled. Birds obviously can only be caught based upon the team you are on.