I've also had an email from Trey (aka Drowse) who mentions that "on the cover of the Made in Heaven vinyl (the sunrise shot, I believe) there is a wake left by a boat.. or something.. but obviously it's not supposed to be there :) ".
I don't have my copy of MIH with me so I've made do with the versions on the Official Queen Web Page, and it's quite visible. So obviously my theory about the shots being identical is flawed. The birds must be creatures of habit!
(There are another couple of birds too! There's one between Roger's head and the lodge (in the evening shot), and there's a bird - which appears in both sunset and sunrise photos - a little to the right of Freddie's statue.)
As Freddie said, "Ha ha ha ha.. it's magic!"
