Hello Spam.
I keep Birmingham Rollers.Small pigeons that have feathered feet and are cute like bantams.
If I remember it right....
Rollers 'roll' forwards in flight.
Tumblers roll sideways in flight.
Tiplers roll backwards in flight.
all to avoid the hawks catching them...They were kept by racing bird keepers as decoys to make a hawk think a smaller bird in a flock was an easy catch...untill they roll just before the hawk grabbed them..
Taken to the degree type Roller or tippler into google and see what they can do...amazing