I have been shooting crows for over 60 years.
The first time you call them, they will just swarm in. Sometimes they send a single scout and you have to get him first.
You can usually call them again but after they figure you out, you cannot call them again to the same location even using different calls. Even 10 years later it does no good to try again.
I learned that somewhere in the South as a teenager. Spot on. The ONLY crow I ever killed, I ran out of the back a house and around to the front as fast as I could go in a house we were living in when I saw them in the front yard and managed to kill one as he took off.
My buddy Bill And I used to hunt crows by jump shooting them when they were on the move. Crows never seemed to fly very high. So the game was to figure out where they were going to go next and then pick an ambush spot. Gullies, ditches, dips, wood lots, anywhere that offered cover. Bill used a 30 inch Parker FxF and I used a model 12, both in 12 ga. Bill did this trick where he reversed two shells in his left hand, he was right-handed, he’d fire twice, hit the open lever and snap the barrels down and pop in those two shells and snap the barrels closed. He could get off four shots in the same time I could get off five. That was nine rounds pretty quick like. Most we ever got was three crows in one jump. By the end of two years all the crows within a five mile radius were pretty leery of us.