Hummingbird nest

Most likely a Anna's but unless you see the bird it could be a Allen's. Anna's will be green on the back and sides and the Allen's would be a copper color on the sides and partial green on the back. Females will be more difficult to tell without the male.

they are so small I've never seen one but I've heard they are the size of a walnut cut in half, the concave part of the nest can only fit a penny, and that the birds make it out of spider wed lichen and feathers.

Please consider adding this spotting to the Animal Architecture mission at http://www.projectnoah.org/missions/8082378