Young starlings fly further in life if they grow up in a drug-filled environment, intoxicating new research suggests. Nests of fresh herbs boost the immune systems and body weight of fledglings. Birds forming their feathers near fragrant herbs fly the nest stronger and better prepared for the big bad world. Male starlings weave fresh herbs into the dry leaves and twigs that their future brood will call 'home'. On the surface this flashy feathering looks like a rather unsophisticated come-on, but some biologists believe that there is more to the males' actions than meets the eye.
Herbs contain chemicals that protect the clutch from parasites, they argue.
Seasoning the nest is the act of a concerned father, trying to keep bacteria and mites at bay. They find no evidence that herbs commonly woven into nests directly affect common parasites. Instead, they suggest that volatile compounds from the herbs somehow stimulate nestlings' immune systems. They call this their 'drug hypothesis'. Plant extracts can trigger reactions against infection and swell the ranks of the body's natural killer cells.