The first example I want to illustrate is the crows where Dorothy meet Scarecrow. For this scene, I needed to have crows flying in the distance. I chose an image that had a number of birds in flight. For some of them, it looked to me like flight paths.
Every production tries to be different. We are adding Canada geese to our cyclone sequence. There was enough variety in the birds in this image to make it look like one bird was flying. I was able to cycle the frame for each position.
Because the background is also animating, I want to scale the birds into place and add one to blow off screen. Open the image below to see the animation. I can't wait to see how it will look in Keynote.