The three legendary birds were introduced in the 2nd pokemon movie and later on added to the gaming series. Their names are Articuno, Moltres and Zapdos. Articuno is an ice type, Moltres is a fire type and Zapdos is an electric type. No one knows of their origin, but in the gaming series, Professor Oak states that Articuno and Moltres combine their powers to cradle the oceans and Zapdos uses his energy to make currents and streams, which is why some fans believe that they are linked to the legendary Pokemon, Lugia. In generation 2 the birds are not in their but can be transferred from generation 1 by using the time capsule. In Emerald if you challenge Pyramid King Brandon and he will have the legendary birds in battle.In Pokemon Mystery Dungeon, each pokemon guards a different mountain. Zapdos has Mt. Thunder, Moltres has Mt. Blaze and Articuno has Frosty Grotto. When you obtain all three, you must have them in your party to talk to Alakazam and go to their friend area and you will have acess to Lugia's domain, the Silver Trench. In Pokemon Platinum, the birds fly around sinnoh. When you talk to professor oak in Eterna city, he later goes to the Eterna gym and gives you the National Pokedex and then talk to him at the Pal Park. They also appear in Pokemon Heart Gold and Soul Silver. Articuno and Zapdos can be found at the same locations as generation 1 while Moltres is with Lugia atop of Mt. Silver. In Pokemon X and Pokemon Y, the birds fly around kalos. The certain starter you obtain will depend on which bird you get. If you choose Chespin, Articuno will appear, with Fenniken,Zapdos will appear and with Froakie Moltres will appear. Unlike before in previous gens, the birds will flee on the first turn so it is smart that you have a master ball with you. After encountering them ten times however (without a master ball) they will retreat to the Sea Spirits Den in Azura Bay and stay there as a stationary legendary Pokemon.