To reward those farmers that have signed up to receive FarmVille emails, FarmVille has rewarded them with another Carrier Pigeon.
The Carrier Pigeons are a decorative animal item and have a "fly" function animation.
They were previously gifted by FarmVille to farmers for initially signing up to receive their emails. Not sure if this was a slip-up or intended free gift repeat. Meaning, many farmers may have two Carrier Pigeons. You can choose to sell your Carrier Pigeon for 500 coins.
Note: The Carrier Pigeon is also available in the FarmVille Market for 17 FV$ or farm cash.