Niantic has revealed that it has reduced the spawn rate of some of Pokémon GO's more common monsters to increase the chances of players finding other, rarer 'mon.
Pidgeys, Rattatas and Zubats are perhaps the most commonly-found monsters in the game, and players have previously complained that they seem to catch very little else. Server-side changes appear to be mixing things up a little, allowing fans to fill their Pokédex faster, but it's worth noting that the reduced number of Pidgeys could impact one of the game's most reliable means of gaining experience.
In more good news, Pidgeys and Rattatas have also been removed from eggs, which should give players a higher chance of hatching a more desirable 'mon. Eevee will now only hatch from 5km eggs, whereas previously it would sometimes appear in rare 10km ones.
These changes precede a major update to the game which will introduce daily bonuses for repeat play.