Beautiful. Don't often see posts with one in and one out.
I'm curious if these trees are hollow or they dig out a cavity inside the tree. Certainly a feat accomplished by a relatively small bird.
The Great Spotted Woodpecker When it comes to creating a nest hole the woodpecker chisels out a cavity within a tree trunk so a partly rotten tree is useful. It may take up to four weeks for a pair of woodpeckers to dig out a nest hole from scratch but the work is shared equally between male and female. I presume this is the case also for the smaller cousin the Lesser Spotted Woodpecker.