migrant Carrion Crow among my Corvids?

We have been having Rooks, Jackdaws and Hooded Crows visit our garden since we moved here, 9 years ago. Rooks and Jackdaws are social birds and go and feed together, after scuots have sourced the best restaurant in the area. Hooded Crows on the other hand are solitary birds; they will wait on a roof, and come in once the action has diminished a little.

The island of Ireland has these members of the Crow (Corvid) family: Rook, Jackdaw, Hooded Crow, Magpie, Jay and Chough.
The Carrion Crow has not reached the SW yet. There might be some in Ulster or on the East Coast, closest to the UK/Europe mainland.

Autumn does bring all kind of migrant to this little corner however and I've seen a notable increase in the Corvids feeding here since late summer/autumn.

What surprises me however, is that Carrion Crows are not known as sociable birds, so what are they doing among a flock of Rook and Jackdaw?
I think that as migrants they mix and mingle with any other flock of Corvids where they can be almost sure of being led to places where food is in a good supply.

Carrion Crow, Corvus corone?




Here you can see the difference in the faces of these two Corvids:
Rook, Corvus frugilega:



As you can see, the two are totally different and one could not be mistaken for the other.