Globe and Mail: Feeding the birds is the most innocuous of pastimes, but it could have a unintended effect: changing the course of evolution. Researchers have discovered that the enthusiasm of many Britons for feeding birds in winter and the gradual warming of the British Isles due to climate change have helped change the appearance of the blackcap, a warbler as commonly recognized in European gardens as robins are in North America. The differences have been modest, involving a slightly …