When I finally did notice it, I was surprised at how green it is. Having lived in the Midwest, I expect old bones to be bleached white from the sun.
However, after a minute of pondering the torrential downpours of the past 6 weeks, I realized that the color of this skull was a precise indicator of the amount of water in the air. Will take a photo of it again during the dry season for comparison. It should be bleached white after several months of arid weather.