I find in my area that coyote vocals works great all year long. Take a listen to the foxpro podcast recently with Torry Cook and Jon Collins. Pups are out learning to hunt this time of year and they are familiar with coyote vocals. I almost always start a stand off with some type of lone howl but I do mix in pup vocals as well as pup & adult fights.A thing to keep in mind is at this time of the year there are lots of very young coyotes on the ground. Using (adult) coyote vocals can scare them off. I like using pup howls to locate.
This past Friday at the first stand we killed 5, a male and female double, 3-4 minutes later a lone female and 3 minutes later 2 pups came in. Started the stand with MFK boone lone howl and within the first 5 seconds of the howl the pack lit up. 2-3 howls later the pair came out. I do not wait long between sounds. 30-45 seconds usually.
I would say more importantly this time of year is hunting where you know dogs are and getting in close if possible. They are still in the general area of their den site. 2 weeks ago I had a landowner send me trail cam pics of an adult and 2 pups. I went in with an hour left of light exactly where the camera was, lone howled once and they sounded off. 5 minutes later I had 2 pups down, one with a shotgun.