Coming this Fall! http://news.softpedia.com/news/Angry-Birds-Stella-Launches-in-the-Fall-Introduces-Five-New-Bird-Types-426600.shtml "Rovio says that when the game launches in the fall, it will be accompanied by both new toys and a cartoon series. The studio promises that it will offer more details about the new mechanics and the story in the coming months." http://www.eurogamer.net/articles/2014-02-13-rovio-announces-angry-birds-stella "There will be plenty of fun and adventure, but the bunch of passionate pals will also have to deal with some serious issues in order to protect their friendship and the environment they live in. Luckily, Stella and her friends are good at finding creative solutions!"
I wish they would release a bird that allows a time-travel aspect, like the prince of persia games allowed, so you could rewind a shot. I'd love to have a mighty eagle-type power up, or a special IAP bird that you pay/earn the use of.