Angry Birds creator Rovio turned down a takeover offer by social games giant Zynga worth $2 billion, reports Bloomberg.

The article details Zynga's acquisition and merger practices, with "sources familiar with the matter" revealing the Angry Birds firm wasn't interested.

There's no mention of when the offer was made, but rumours of a potential takeover bid emerged in November 2011.

Rovio's latest, Angry Birds Space, achieved 10 million downloads in just three days.