Looking at its slender silhouette, streamlined for flying from branch to branch, who would have any idea of the migratory exploits of the little black-headed warbler? The secret of its ability to cross wide open spaces in autumn is hidden in the little black beads of the elder tree. They contain phenomenal quantities of nourishing, stimulating, protective and restorative substances that help the bird resist the stress caused by its intense muscular effort. In return, the warbler proves to be the best disseminator of the shrub’s seeds, which it releases in its droppings. A vital pact binds the two partners: never you without me! In My friend the eldertree, discover all the facets of this charming union, of which man is, incidentally, a very ungrateful beneficiary!