Lots of possible woodpecker holes next to marshland? Not sure which type.
No identification made yet.
No interactions present.
Could be Redstart. woodpecker, Nuthatch, Starling or a whole host of hole nesting birds.
Wild Flower Society member
...but it would have originally been made by a woodpecker of course. Most likely a great spotted I think, green woodpecker holes look less neat than this, and slightly oval.
Lat/Lng: 50.8, -0.9
OS grid ref: SU7801