Nice shot! The colors are warm and well balanced. All the right details are in focus and the out of focus background is just perfect! A cool tone in the sky, not too bright, and all warm tones below. Nothing in the background is too distracting to take away too much attention from the bird. I really like the hazy tree branches and their specs of green sprouting from them, makes one think of spring.
The figuration of the photo very nicely fits the 'rule of thirds' and is centered impeccably to feature the bird.
Perfect timing as well, it looks as if any second the bird is going to spread it's wings and fly away!
The only way I think that you could improve this photo is that the bird house is more in focus than the bird itself, seeing the detail in the wood is nice, but can be distracting to the main subject. Making sure your camera focuses on the bird will make sure the eye is drawn directly to it (Which is hard with the bird fluttering around!).