part of series of 4 - expert commentary: "They are all Ravens. They are indulging in a behaviour which is common at this timeof year - parallel flying.
Each pair flies along often quite slowly and close together and mirror each others movements - it reinforces the pair bond. It's actually well know in humans also - mirroring, not parallel flying - and serves the same purpose, particularly early in courtship!
Often 2 neighbouring pairs will come together and fly alongside each other, perhaps just for social reasons (they are very sociable birds) or for fun (Ravens are known to play) and sometimes antagonistically."