Starlings use aromatic herbs to decorate their nests. As science studies the human benefits of aromatherapy, starling research shows the use of herbs helps a chick's immune system. The herbs contain the same essential oils as we use, but in starlings the oil is absorbed through the shell, helping to boost the embryos white blood cells which fight infection. Chicks reared with herbs grow faster and cope better with stress when they leave the nest. Twice as many birds from herbal nests survive their first year. In a dangerous world the smallest variation in fitness makes the difference between life and death.