Many birds have pigment glands that deposit colors on their eggs as they pass through the mother's oviduct. In the case of the American robin, the eggs are an eye-catching blue. Normally, a robin will lay three to five eggs per clutch. It takes about two weeks to incubate the eggs. The mother robin will spend most of her time sitting on the nest, but the male bird may occasionally sit on the eggs to give her a break. After hatching, the young robins will remain in the nest for about fifteen days.