They are all corvids.
Often, a flock of ravens is referred to as a “murder” rather than a “flock.” This is because of old English lore, which says that one or more ravens will accompany armies into battle and either fly down from the air to feed on corpses like the vultures in Rome’s Colosseum or they would get ahead of the army by flying over what might be an ambush site like Hannibal before crossing the Alps. If there was no ambush waiting at this location, then there would be none for when they arrive at their destination. For this reason, you may see ravens accompanying armies with banners or flags, and these communities that follow Carrion often call themselves a “murder.”