Angry Birds in US retail, UK parks push LONDON (Reuters) - Angry Birds maker Rovio is teaming up with a major U.S. retail chain to sell its merchandise, and plans to open themed activity parks in Britain, as it continues to expand beyond mobile games to establish a Disney-style brand, it said on Tuesday. Peter Vesterbacka, marketing chief of the Finnish start-up behind the world's most downloaded game, told Reuters that Rovio saw itself as an entertainment brand, not just a games company. Angry Birds, in which the player uses a slingshot to catapult birds to destroy green pigs hidden in fortresses, has been downloaded more than 700 million times, and is the fastest-growing game on Facebook. Rovio raised its profile hugely last year by hitching a game to the hit animated movie Rio, made by News Corp's 20th Century Fox, even burying a clue to the game in the movie studio's Super Bowl ad. The company's value has been estimated in recent media reports at up to $9 billion, little more than two years after it first released Angry Birds for the iPhone. "It's as good a guess as any," said Vesterbacka, comparing Rovio to Facebook games maker Zynga, which went public in December and has a market value of $9.6 billion. Now Rovio has signed up a top U.S. retailer to put its branded toys, books and T-shirts in dedicated areas of thousands of stores nationwide, timed to coincide with the launch of its new Angry Birds Space game this week. The company also plans to open branded retail stores in China soon. Rovio did not want to name the U.S. retailer ahead of the official announcement but said it would be bigger than an existing partnership with bookseller Barnes & Noble, where visitors to the stores can pick up game credits for free. Rovio also said it planned to launch themed activity parks in Britain, which was its original breakthrough market for the Angry Birds game, as its first expansion outside Finland. Its next targets will be in Asia. The parks, which will be built in partnership with Finnish playground equipment maker Lappset, will feature Angry Birds-inspired swings, sandpits, climbing towers, slides and outdoor arcade games. More like adventure playgrounds than Disney's massive theme parks, they will mostly be in cities and towns or attached to existing large theme parks. "We can't afford to invest billions into theme parks," said Vesterbacka. We are a tiny company from a tiny country. Rovio has about 300 staff, up from 50 a year ago, and has had to move out of central Helsinki to new, bigger headquarters next to mobile phone maker Nokia. Editing by David Holmes, Gary Hill