Nuthatch home improvements

We spotted this nuthatch, busy working on a nest hole in an old oak tree, when we were out walking in Teesdale last week.

Nuthatches usually nest on tree holes, selecting one that has a slightly larger opening than they need and then partially blocking up the hole with mud. We watched it make several trips down to the edge of the river Tees to collect the necessary building material but ....

.... it also came back with water and then seemed to regurgitate it as it entered the nest - you can see droplets hanging from its beak in this rather blurred photo. I suspect that what it was doing was softening the mud that was lining the entrance but had dried in the sun, because then ....

..... it entered the nest hole and then squeezed out again through the muddy aperture ....

..... using its body to mould the perfect size of entrance hole.