Evolutionin action

摘要

As children we learn about evolution from thrilling images of fossilised feathered lizards and early humans, illustrating how species split and changed over millions of years. These grand stories mean that we often think evolution operates over geological timescales, but in fact it can be fast - taking place under our noses.Enter the blackcap. Like most warblers in Britain, this migratory species does not generally visit gardens, frequenting woodland, hedgerows and scrub, and flies south for winter, normally to the Mediterranean. But roughly 40 years ago people started noticing increasing numbers of blackcaps in the UK at the wrong time of year. Even more surprisingly, these wintering birds were often seen in gardens.