No House Wrens (?)

It can be strange to experience the peculiar shifting habits of nesting birds.  Last year, I had serious problems with pesky House Wrens filling the best nest boxes with their stack of twigs, and in one case hogging a bluebird box.  This year: two good boxes put to good use, and no wren nests anywhere I can tell.  They ignored all three of my premier boxes and probably ignored the remaining four.  I am delighted with these results: let my neighbors host the lousy wrens!   But doubt remains...will they eventually return in a later wave?