Immanuel Kant's Sparrow
b'The adoption of foreign song elements occurs under natural conditions in various songbird species including the house sparrow Passer domesticus, even though it may go largely unnoticed by humans. House sparrows singing canary song have been known by hobbyists for a long time. My study is the first to analyse the imitative abilities of house sparrows in detail. \\nI used an integrative approach considering features that are particularly important for the degree of vocal learning that can be displayed by a species. These included (1) a genetic predisposition, (2) body condition of the parents, (3) food availability during early ontogeny, (4) social factors, (5) neuronal mechanisms, (6) hormonal states, and (7) body size and morphology of the vocal tract. \\nHouse sparrows singing canary-like songs provide a rich tool for further integrative approaches. I suggest an interpretation combining all the above features under the perspective of female choice. Instead of searching for a \\u201ekey adaptation\\u201c or single explanation for the imitative ability (song learning ability) in passerines, it might be more appropriate to focus on the multiplicity of factors involved in song production that - shaped by different selective forces - promote the highly specific song adaptations.'