Oh, there can be quite a difference during different times of the year. Once they get it in their heads to start breeding, vocals work great. When the pups are on the ground, puppy distress calls are killers.
I use the 3 strikes rule. Try a call sequence 3 times. If nothing shows up, change something. It might be the volume, it might be adding or subtracting calls to your sequence, might be how long you are calling, or the order of your sequence. But change ONE thing. Then run 3 more stands. This will allow you to positively identify what is working and what is not and will let you zero in on their pattern. Too often guys make too many changes and can't identify what is/is not working.
Once you lock into their pattern, you are going to rack up more fur.
