This is one of my favorite Labyrinth images. What I like about this one is the left two thirds of the photograph is the same doorway photographed from two different angles. That is what made the indistinguishable blending of the two frames possible.
I never even saw the bird in the sky until I got home and looked at a full size image on my computer. Even then I thought it was a defect on the sensor. Then I looked again. Everything in photography is a combination of skill and luck. Skill got me in the right place at the right time. The bird flying through the frame in the right place was serendipity.