Letter: Woodpeckers, gannets, and head injury.
D000222:Adaptation, Physiological; D000818:Animals; D001717:Birds / Q000033:anatomy & histology*; D001924:Brain Concussion / Q000517:prevention & control; D006259:Craniocerebral Trauma; D006260:Head Protective Devices; D006801:Humans; D012886:Skull / Q000033:anatomy & histology*