Disaster.

My latest vist showed traffic to the box was way down and still no activity in the access tube.  I climbed up to investigate.  There were no dead bees in the tube as in days of yore, but when I blew into the clear access tube, it was apparent that the interior end was completely blocked.  Later, I gathered some tools and returned - a straightened coat hanger and a shotgun cleaning rod and brush being the core.  I used a drill and the hanger to rip the foam inside the wall, destroying it's integrity.  Tests indicated that this would not really open a passage, so the cleaning rod followed to grind out the debris and leave a passage the bees could use.  It must have worked.  as I was packing my gear, a half a dozen bees made a noisy transit down the tube to express their displeasure. Fortunately for me they were few and disoriented and did not mount an attack, if anybody followed them I couldn't say.  I hastily reinstalled the transit tube connection to the box and departed the scene, lest they get their bearings and return for a little payback.  Now I am just crossing my fingers and hoping they return to using this opening.  At least there is still a fair amount of activity still in the box, even shut off from direct access to the main colony - perhaps they will mend the rift on their own.  If I have to try to seal their alternate under the soffit, it may well prove to be the undoing of this effort.