This is how I would do it. Shoot the two shoots. For the 2nd shoot hold on the sky for a while before the camera pans down. Or for extra points pan the camera up hold and then pan down to end shot. Then take the first shoot and mask out the sky using the roof of the house as a guide. The shot is so short you can manually do the mask with keyframes or use Mocha which rocks at making tracking masks. If you did the static then pan down use motion tracking so the image moves with the roof. If you did the camera move then you should be done. Add in the fake birds for good measure. Not sure if this helps but best of luck.