Mark Sturtevant wrote:
Robin eggs that I see are sky blue. But I don't know if there is variation.
As for the lack of a nest, there is egg robbery where a bigger bird (like a crow) will carry off an egg, but it can be hounded into dropping it by the parents.
Thank you very much Mark. I appreciate the information. One source I checked showed nothing about this being a robin egg. But then I checked another site and it said it was definitely a robin egg. It also pointed out as you did about other birds carrying off eggs and/or the mother getting rid of it if she suspects the egg is not going to hatch, no idea how she might know except mothers of course know EVERYTHING.