The area where I live has a lot of Hooded crows but they do not seem to gather together as much as in other areas. They tend to live in pairs and keep to their own. Lately there has been a strong expansion in the numbers of Corvidae with Jay, Crow and Magpie populations all booming.
Anyway to return to your initial question I have heard a similar thing about Magpies. When they gather in large groups these groups are called parliaments because one of the birds usually appears to be addressing the others gathered around it, like a parliament of old.
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