On one of my morning bird walks, I witnessed a home invasion. It seems that a pair of Violet-Green Swallows had selected a cozy oak tree cavity for their nest. They went in and out, but so did an Acorn Woodpecker, a starling, and a pair of White-breasted Nuthatches. Since I’d frequently seen these swallows in the same tree the year before, I assumed that the tree cavity was theirs. Not so fast..