it has been my experience that lone howling to coyotes will most times NOT get a responce and group howling WILL get a responce almost every time.i use these two types of howling for two different reasons.group howling i use for locating packs in different areas,i use a tape for this.now this may also get them to come in becouse they think a pack has enterd there territory.but most times they will responed vocaly to let the intruding pack know that there tresspassing.they tend to not want a physical confrontaion with another pack becouse this can get deadly.they would rather try to intimadate the tresspassers vocaly.lone howling will make them come in but most times silently.when you howl by yourself you must be on your toes becouse if there is a pack with in hearing distance they will most likely be coming in to kick the intruder out or kill the intruder.this holds exspecialy true when you do a deeper toned male call.but be ready for they will come in spread out and quite possibly all around you.if its mating season and you do higher pitched female call you may get the alfa male to come in becouse he's lookin for some more lovin if ya know what i mean.this may also attract a young wondering male(a loner)becouse he's always lookin for some companionship.when using a howler to call in coyotes its important that you also know how to do the challange bark howl.this call is accualy easyer to do then the lone howl.any of the how to tapes or video's will show you how to make this call.if you spark the interest of a pack or even a loner male he may challange you vocaly.you must be able to snap right back with your own volcal challange.if your succsessfull in challanging him he will be coming to kick your butt so be ready and don't move a mussel.when that coyote poped out you needed to make a distress call.this creates the illusion that a stray coyote has enterd his domane and killed some of his food.after the distress call,follow up with another howl.its at this time when you have seen a coyote take notice to your calling with howles that you may get a callange bark howl.