‘Odd box’ mystery visitor

I put the odd box up yesterday… here it is ‘in situ’.

I left the the computer monitoring the odd box today. When I played it back, I was suprised to see this head look in…….

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I think this is a nuthatch…  would welcome any other ideas. I have nuthatches visiting my feeders regularly and on checking in my bird book, it said they do nest in nestboxes….. that would be brilliant!