iPhone, iPad and iPod touch users have a sick obsession. No, not their tendency to adore their iOS devices a bit more than might be considered healthy — they love birds. Right now, the top five paid apps in Apple’s App Store all revolve around fat little birds being hurled across the screen. Some are being thrown at things and others try to avoid things, but all of them have one thing in common beyond the fact that they’re fowl: these games are as casual as casual games can be. As companies begin to focus on more immersive mobile gaming, one can’t help but wonder if the bulk of mobile gamers are ready for the transition to a more sophisticated brand of gaming. It could just be that they’re happier watching birds glide across the screen atop different backgrounds over, and over, and over again.