1. Shadows aren't ever blown, only highlights. Rarely do you have pure black pixels in an image, but very easy to have pure white, thus blown highlights.
2. In order to keep both the sky and a bird within the dynamic range of the camera, it is very common to bring up the shadows of the bird. A silhoutte of a bird is quite frankly boring IMO.
3. If you don't want the bird to be shadowed, then you will often have to blow out the sky to get the exposure on the bird correct out of camera.