The App Store found in iTunes is only for iPhone/iPod/iPad apps. Mac apps can be found on the. Angry Birds is available for Mac for. You can also play for free online at.
Download Angry Birds Friends (free For Mac Free
Note that iPhone and iPad apps are not linked to desktop Mac apps, so when you buy an app for an iPhone or iPad, it does not come with a Mac version and there is no guarantee that a Mac version is even available. Sometimes apps are available on both the iOS (iPhone/iPad) App Store and the separate Mac App Store, as is the case for Angry Birds.