Umpire's ladder?

But what's the game?
A field-sport without a name.

A strange place to see this. No branches lopped from the tree, so I guess that's not its purpose. Nice high perch for bird-watching, maybe? Though not easy to access.

It's been a day of two migraines, each preceded by the usual zigzag lines and briefly impaired vision. A flash of sunlight through the window I think triggered the first. But after a quiet morning, a refreshing walk, and a relaxing soak in the bath, the repeat was a bit of a blow. Now taking my slightly achey head to bed in the hope of a fresh start tomorrow.