Driving parents cuckoo

摘要

Do nestling birds signal their food needs honestly to their parents? A study of begging reed warblers shows that they do, but that parental sensitivites to vocal and visual cues can be exploited by an invading cuckoo chick. The distinction between wants and needs lies at the heart of thinking on how dependent offspring communicate with their parents. Does a newborn send accurate and truthful information about its nutritional requirements, thereby helping its parents to allocate limited resources for the good of the whole brood? Or does it (unwittingly) practise deception, using 'psychological weaponry' as a foil against its parents' physical superiority, and manipulating them into skewing investment towards itself at the expense of its nest-mates?