You got it! She's a Nuthatch. Wait! What are the Chickadees doing?
If you look very closely there is a bit of a bird visible in the lower right of the cavity. What is she doing in there?
Look at that! She appears to have a beak full of pulverized wood. They have been excavating.
Wood Chip Beak takes off and the mate shows up.
The mate pops into the cavity and is doing something upside down. Then she pops out...
And the mate pops back and peers into the cavity.
And goes in head down, tail up.
Then flies back out with more debris. The mate returns and disappears into the cavity.
The she pops out with even more debris.
Chickadee returns and leans in for several minutes.
He backs out a little and keeps at whatever he is doing.
Then further in again. I suspect more excavation is going on.
Yup. We've seen this excavation position before.
In the meantime, the mate is sitting in the neighbors pine tree with something besides wood debris in her beak.
When I look back whatever it was is no longer in her beak.
She gives me a look, marches down the branch...
Gives me another look...