Distant silhouette

Photo taken this lunchtime from my bedroom / office window, with great difficulty, on a phone through binoculars. It’s actually a pretty clear silhouette (if you zoom in far enough). I was taken by the long tail, which was bobbing in a wagtail sort of way. I have recently seen grey wagtails on the river nearby. This bird seems all dark (but the sun was behind it so hard to be sure). Would a grey wagtail be perched up on a telephone line?