I realise this is a rubbish photo, but the bird was gone before I could get closer or focus. Never thought anything about it at the time, but just thought it was a Grey Wagtail, as the yellow had caught my eye. Now looking at the photo (rubbish photo), I am thinking Yellow Wagtail, as I'm not seeing any grey in the uppers. Bird also looks rather upright. What do you think?
Photo taken this morning.
Photo taken this morning.