Here are my thoughts on the different options.
#1 Take the shot at 542 yards. Even though I think I could have hit him I didn't every really consider this option for two reasons. Most importantly the gun/bullet combination wasn't a good choice to be shooting at a coyote at this distance. Second and almost as important, I really like calling them in more than shooting them.
#2 Try to stalk closer for a shot without calling. I think this could have worked but I would rather call in a coyote than stalk a coyote.
#3 Start immediately calling as I was planning to before I saw this coyote. This would have likely worked but I was concerned the coyote saw/heard me moving into my stand. I was skylined temporarily moving into the stand and the gravel I was walking on was noisy.I was hoping if it did, it would forget about it after napping for a few minutes before I started to call.
#5 Move stand locations before starting to call. I think this could have worked too but it would have been risky. Besides having the sun in my face, I was really happy about everything else with my stand location. Moving forward or to the right would result in a lot of noise because of the steep gravel hillside I was on. It would have also left me wide open exposed with the sun glaring on me. Moving forward would have given me a better view of the Creosote brush that the coyote was likely to disappear in when I started calling and put me in reasonable rifle range if the coyote decided to not come in but I thought the risk of spooking the coyote while moving forward wasn't worth the benefit.
Backing up and circling to the right would have been less noisy but there is still a chance the coyote would spot or hear me. I was actually surprised that it didn't seem aware of me already.
Overall I'm happy with the decision I made on this stand. I've been in this scenario a couple other times where the coyotes decided to run the other way when I started calling. I think I could have called this one into less than 20 yards but after missing a couple in this area and having a few others get away without getting a shot, I wasn't going to pass on non moving broadside coyote at 54 yards.
