#7 I change opacity on Layer one to 80% by using the Opacity Slider on that layer. Then I clicked on the other layer (Background) in the picture to activate it and use levels to darken the bird layer slightly without darkening the sky. This is also a time that you could create a layer mask on the Sky Layer and paint any sky off bird that is showing on it. Then you can save as layered of Flatten Layers to make final adjustments to entire picture (sharpening, NR, etc.).