Bluebirds at Green Lakes

Green Lakes SP staff have set out lots of bluebird boxes. Joli and I walked in the upper meadows of the park today and observed many nesting pairs. I believe, though I know it seems unlikely, that in this twin set of boxes there are two pairs of bluebirds, even though usually a second box is only adjacent so that there will still be a box for the bluebirds after the sparrows have occupied the one they want to call home.