Hmmm flying in formation like that sounds more like waterfowl. Could it be cormorants? Are you by the shore or near a large body of water? They can be all black like crows and the begging sound of the double crested cormorant does sound kind of seagull-y?
If they’re fish crows though, that’s cool, they’re rarer than the carrion crows we’re more used to. In any case I’m glad if I could be of help and I hope you continue to enjoy listening to and watching birds!