Appeared to be nesting on a building on Staple Island. Was described by a volunteer as a juvenile Whinchat but looks more like a Rock Pipit to me.
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I'm not sure how well it holds up, but I remember being told that meadow pipits have pale, flesh-coloured legs and rock pipits dark, blackish brown legs and that that was a good way to tell them apart. Maybe it's the light in the photo but the legs look fairly pale, could it be a meadow pipit?
Just like in Willow Warbler and Chiffchaff identification, leg colour is too variable to base an ID upon. This bird is clearly grey toned above, with smudgy, indistinct spots below, both of which (together with the thick legs, which still look quite dark to me) make it a classic Rock Pipit.
You're right that leg colour is useful, but it is only one of the things to look for. As with so many tricky species (like Marsh/Willow Tit, for example), you have to look at a series of different features to arrive at a likely ID.
My Flickr photos...
Thanks for the further detail and advice ophrys, I will keep practicing my pipits! :o)
Lat/Lng: 55.631213333333, -1.6241866666667
OS grid ref: NU237375