Strange Raven behaviour

A friend of mine who ,like me, spends a lot of time counting certain species of bird has been asked by an experienced birder if he could explain some strange behavioural sightings of Ravens in the Yorkshire Dales. Ravens are regular breeders in small numbers in the Dales but sightings like this of up to 12 birds in the air together is a strange one to us. Neither my friend or myself have seen 12 Ravens together in the UK so a couple of sightings like this is both exciting and very strange. We are not sure if they were passing through or a number of families that after breeding have grouped together. I wonder if any Forum members have come across anything like this before if so I would be interested in what circumstances.