Finlands Rovio, the maker of the Angry Birds mobile game, said it has hired Pekka Rantala from beverage maker Hartwall to take over as its new chief executive by the beginning of next year. Current CEO Mikael Hed, son of board chairman Kaj Hed, will join the companys board of directors as well as take on the role of chairman at Rovios animation studios. After scoring a global breakthrough with Angry Birds in which players use a slingshot to attack pigs who steal birds eggs, Rovio has expanded the brand into an animated TV series and merchandising of toys and clothing. Rovio said several years ago it could go public in Hong Kong or New York, but has later said it was not planning an initial public offering any time soon.