Escaped before I could photograph the belly, but it was yellow.
Found in compost pile.
This bird was found in a coniferous tree in November 2016 at the south rim of the grand canyon along the Bright Angle rim trail; he/she was observing passerbys; this bird has a patch of white under its chin, but the rest of the belly is a drab-gray/white; the head, back, and tail is a brilliant blue; the head has a white stripe above the eyes and a patch of dark gray behind the eyes; the tail is long.
https://www.allaboutbirds.org/guide/Woodhouses_Scrub-Jay/overview