When I get a pack to howl back at me, I normally either try to howl back just like one of the coyotes you hear or maybe throw them a challenge howl. If neither one of these work then I have had luck with pup distress. If you call for awhile and don't see anything, just sit in silence and wait for 10-15 minutes as they will sometimes just show up to see what all the fuss was about. Hope this helps