I just wanted to use this as a platform to show this off, a proper write up of the method will come later (having too much fun just playing for now at the #gafesummit (NZ North Island!).
As an update to this post, (much later than it should have been...) this was created by choosing a background image, in this case, 90 Mile Beach at Ahipara. Then I found an image of a seagull, making sure to do a Google search for the .gif filetype. This is then added to the slide, and he whole thing is copied.
With the new slide, move the gif image a tiny bit in the direction you want the animation to move. Keep repeating the process until you have the animation you want.
Simple but effective, and something a student could do really well.