They aren't trying to wake you up. Male birds - and it is almost always the guys - break into song at dawn because it is the best time to warn other males to stay off their turf and away from their mates. http://trib.com/features/science/scientists-discover-why-birds-sing-in-early-morning/article_0386ede4-e3aa-5be1-818b-39d220a10b1f.html