Angry Birds fans are in for a Christmas treat, as Rovio has just released version 1.5 of the iPad Angry Birds HD version - bringing 15 new levels along for the ride.The new levels appear in a new adventur titled "Ham -Em High" that has a distinctively wild-west flavour to it.There's a new golden egg up for grabs as well, and the much anticipated Mighty Eagle has now finally flown in.Available as an in-app purchase, for 59p, the Mighty Eagle will help you when you get stuck on a level. You simply throw in a can of sardines and along comes the Eagle to save the day. A bit like Lord of The Rings, but with sardines. You can only use the Mighty Eagle's help once an hour though."We\u2019d like to take this opportunity to extend our infinite gratitude to friends of our fierce birds everywhere", read a Rovio statement."We thank you sincerely from the bottoms of our fluffy hearts for making Angry Birds the highest rated and best selling game ever on iTunes".Angry Birds HD is in the App Store, priced at \u00a32.99. If you've not played it - then get involved. It's Pocket-lint's Best Game of 2010 don't you know?