Who might live here?

I went out to the meadow area today as the grounds team were planting a new tree and wanted me to confirm where it needed to go.  The new tree is currently very small and I hope it will grow quickly and that the local children will not break it.  While out, I noticed this hole in a tree which is still alive, I had never noticed it before.  I tried to take a photo inside and it just looked wet. I will keep an eye on it and see if anything moves in.

Working at home today and I did not get much done, not sure why.  Had a busy evening cooking, doing a bit of house work and sorting out some paperwork.  Off to do a bit of Yoga now before a shower and bed.

Not many steps 8,700 but am going to do a bit of Yoga now which will add a bit more activity.