Ruby-crowned Kinglet's yellow feet

Today my birding activity was confined to my backyard. I set up my WingScapes Birdcam aimed at the suet feeder mostly to try to catch the Townsend's Warbler in the act. I didn't know until this evening when I downloaded the captured images that a Ruby-crowned Kinglet had also stopped in. Unfortunately, he was photographed when he was inside the Starling-proof cage, but I still like the photo because you can see both his red crown stripe and his yellow feet, which are difficult to see when you are trying to watch through binoculars a flitting, hyperactive bird in a shadowy, leafy thicket.