I can't answer this but if I might make a suggestion - try your own howls at a few different locations.  I've had surprisingly good success doing this over the years (about 20% success rate if I had to put a number on it).  Actually got to see wolves on 2 separate occasions doing this at various spots in the park.  

I think the park does the howls when they have a very high rate of probable success but failing that it never hurts to give it a try!

Oh i'm well aware of the lack of success of the official program!  and we've seen that wolf presentation once every couple of years. it would just be neat to be a part of the full deal should it every happen. we've heard them in the past on a couple of backcountry trips with my older two, but never the younger kids. thanks for the Basin Lake suggestion. the east side of the park is not something we've explored a lot as we're coming in from the west side always. but it's on the list. are those roads you see on the maps actually accessible alongside basin lake, travers and the observatory- can you actually drive up those?