Pat the Birdy is an achievement in Plants vs. Zombies 2 which requires the player to hit a Seagull Zombie with butter. It is worth 10 points on Game Center for iOS devices and 1,000 XP on Google Play Games for Android devices. To earn this achievement, the player has to plant a Kernel-pult and let it lob butter at a Seagull Zombie.
The name of this achievement may be a reference to a former American musician named Patrick Schneeweis, who was also known by his nickname "Pat the Bunny".
An easy way to get this achievement is to delay a Seagull Zombie with a defensive plant, such as a Wall-nut, Tall-nut, Infi-nut, a stalling plant like Stallia or Stunion, though keep in mind that Iceberg Lettuce will not work. Be patient as the Kernel-pult in question may or may not lob any butter at all. In this sense, two or more of them may be better for getting the achievement. Be careful not to let any other zombie get in the way of the Kernel-pult. The safest and the easiest option is to use Plant Food on a Kernel-pult as soon as you see a Seagull Zombie.