Peter Berthold (1939) is one of the leading German ornithologists and internationally acclaimed specialist on bird migration. Especially his studies on (the migration of) the blackcap (Sylvia atricapilla) are famous. So is his book ‘Bird migration, a general survey‘. From 1998 till his retirement he was director of the Forschungsstelle für Ornithologie der Max-Planck-Gesellschaft. His list of honours and awards is even longer than his beard.
Professor Berthold has never been observed (adulthood, by professional observers, on the public record) to be beardless.