So Where Are They Going?

It's deep in March, and I know from long experience that the White Breasted Nuthatches are alost certainly into their first brood nesting cycle. And indeed there's at least one bird working the suet feeder hard. I've been watching it (or them?) for days. But instead of beelining for one of my 11 nest boxes, it's always a course north across the street. I have seen no traffic at any kind recently at the box used by this species last year, except for early visitation a few weeks ago. So where are they going? Is there another box they've found? Or, unlikely as it sounds here, a natural cavity? what turned them off to the box which was so favorable last time? This is the unpredictable nature of songbirds. Even the best ornithologists don't fully understand nest preferences: what little things can be a deal killer at any given point in time. Well, I'll be hoping whatever the nuthatches have works out for them and that they find my cafe a favorite stopping point.