A new Mega-Evolved Pokemon is now available in Pokemon Go. As a reward for collectively completing two million Mega Raid Battles during the first week of the Mega September event, Mega Pidgeot has begun appearing in the game as a Mega Raid boss.
With Mega Pidgeot's arrival, you can now Mega Evolve your own Pidgeot once you collect enough Pidgeot Mega Energy. You'll earn this energy for defeating Mega Pidgeot in Raids. You'll need to amass 100 energy to Mega Evolve your Pidgeot for the first time, but subsequent transformations will take less energy. Niantic also says it is tweaking Mega Evolutions to give players more ways to earn Mega Energy outside of Mega Raids.