The Ultra Bonus Event is now underway in Pokemon Go, bringing an influx of Gen I Pokemon with it. For a limited time, Pokemon originally found in the Kanto region will appear much more frequently in the wild. That isn't all, however; the three Legendary birds Articuno, Zapdos, and Moltres have all also returned to the game, but for only a few days.

From now until September 20, you'll have another chance to fight the three Legendary birds in Raid Battles. While the three are available, the duration of Raid Battles has been extended to 90 minutes, giving you some extra time to battle and catch them. Niantic also says you'll have a chance of running into Shiny versions of each Legendary.

On top of that, you'll now be able to get your hands on some previously region-exclusive Pokemon. Until September 30, you'll have a chance of hatching Farfetch’d, Kangaskhan, Mr Mime, and Tauros from 7 km Eggs. Each of the aforementioned Pokemon is typically only available in a certain part of the world, making this many players' first opportunity to add them to their collections.

On the same day Articuno, Zapdos, and Moltres leave Raid Battles, another Gen I Legendary, Mewtwo will take their place beginning at 1 PM PT / 4 PM ET. This isn't the Psychic-type's first appearance in Pokemon Go, but it has up until now only been available through the invite-only EX Raids. This marks the first time Mewtwo will be available in regular Raid Battles, making it much easier to finally capture one. It will appear in Raid Battles until October 23.

While not part of the Ultra Bonus Event, players still have only a few more days to capture a different Legendary Pokemon, Regirock, which is also scheduled to leave the game on September 20. Pokemon Go's next Community Day event will take place not long afterwards, on Saturday, September 22. This time, the featured Pokemon will be Chikorita, one of the three starters from Pokemon Gold and Silver.

Source: GameSpot