American robins (Turdus migratorius) are busily making and sitting on their nests in our cottonwoods. The female robin builds the nest by first forming dead grass, twigs, moss, feathers and other materials into a cup shape. We have horses, so “our” robins incorporate horsehair into their nests. The cup is then reinforced from the outside using mud from earthworm cases creating a strong, secure nest. Finally the female lines the cup with soft materials before laying three to five blue green eggs. This robin is already “sitting” on her nest outside my study window (Lookout CA).