In the 90's in the Dakotas before mange took out the majority of the fox, this is virtually all we did. We called the first stand in the morning and last one in the evening and stalked all the rest of the day. It was one of the most enjoyable ways to hunt. The reds are slowly making a comeback and we get a few coyote stalks in a year as well, but it isn't like it used to be.
A fox is by far the easier target to sneak up on as with a coyote, you need very good snow conditions, hopefully some obstruction to hide your approach, and a bit of luck. Always be careful of the animal's slighest movements as if you see movement they are probably looking at you. If you see movement, stop, because if you stand totally still for long enough, many times they will put their heads back down and go back to sleep as their eyesight is sensitive to movement. If they tuck back in, this will allow you to get into a shooting position or continue your sneek.
Great pictures. Coyotes and fox are very pedictable as you have shown. When spotting we used to pull up to the top of a hill, you could virtually look over a whole section and pretty much know if there was a bedded animal exactly where he would be. Spot and stalk is a great way to hunt.
As you have said, wind and sunshine are the primary factors as they will always be laying out of the wind soaking up sunshine whenever possible during the winter months. If they have to choose between the two, wind almost always wins. This is the reason why a bright sunny day in the winter time with a Northerly wind was always great stalking because fox and coyotes could be out of the wind and soaking up sunshine at the same time. I have stalked both fox and coyote at temps below -20 but as long as the sun was shining and they were out of the wind, they were nice and cozy.
