Very interesting read!
When you look at the yellow circles of coyote territories, this might, maybe, possibly, explain coyotes coming, or not coming, to a call.
For example, if you are set up in the middle of a territory, you might only get one or two coyotes to show up;
however, if you are on the edge of 2 territories, it might explain why you have multiple coyotes coming from different directions.
I believe that is why they howl, not to say 'Good morning or afternoon' to other coyotes, but to find out who survived the day/night. If no coyote howls from an area for a day or two, it might be ripe for a territory takeover.
You Colorado guys might know Andrick Ponds SWA, a 711 Acre property. From about 1992 until about 2007, when John Andrick sold to Colorado DOW, I was just about the only guy he let out to coyote hunt. It was my honey-hole.
Mot of the times I went, I would kill 2-3 coyotes, and I would go twice a month, October thru April. This property had such good small game habitat, that there was never a vacancy of coyotes. And, it seemed that the replacement coyotes would have very similar territories to the coyotes I just killed.
AS the old saying goes, 'Nature abhors a vacuum'.