"I'll bet when our prehistoric ancestors first dug for tubers and planted seeds in Europe, one of these little robins appeared within a couple of days. Other animals must have done the same job for them before human beings did. Once, not so long ago, wild pig were common all over Europe, and they're great diggers and rootlers. So maybe the robin's boldness and friendliness with other kinds of animals started in prehistory, even before human beings arrived in Europe."