When I needed to go in to take a den cold with out hearing them I would first go to the watering holes and walk around them looking for their tracks taking note of what side they were on then hit the draws on that side to look for more tracks . I looked for tracks in the road going to the watering holes any sandy blowouts , trails into and out of draws , along creeks ect. Tracking is an essential tool for your kit you can tell the male from the female or if you have two males running together or two females and a male . Their foot prints are like ours not the same close but different . When coyote have pups they have to travel back and forth to feed them so you will notice heavy traffic closer to the den tracks coming and going on the same trails or the bottom of the draws . I have seen green grass beaten down in a path about 3" wide going to the den . A dry pair can be a fit to get stopped from killing as they will have a territory but don't need to go back to the same place all the time . They don't always howl or answer a howl , they may not even howl to a siren . Some ranchers use sirens to get their cows to come to the feed , so then the coyote get used to it and don't respond . I have had coyote come into it and not howl .