I've been tending nest boxes in Oklahoma and West Virginia for nearly 40 years. An observation from Oklahoma in the early 1980s came to mind.
A pair of Eastern Bluebirds had built a nest in a box in late March. Before any eggs were laid, a Bewick's Wren built its nest on top of the bluebird nest. And then a Carolina Chickadee built its nest atop the wren nest. Finally, the bluebirds returned and took control. They fledged a brood of four chicks.
Also in Oklahoma I once found a cowbird egg in a Bewick's Wren nest in a nest box.
These were all one-time events. To see unusual things, spend lots of time in the field.
Scott Shalaway, Ph.D. 2222 Fish Ridge Road Cameron, WV 26033 304-686-2630
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