BBC: Climate change is to blame for a drop in the number of some birds that visit Britain each winter, the RSPB says. The charity said many wildfowl no longer needed to migrate as far as the UK from places like Greenland and Siberia because of warmer winters. Numbers of seven regular visitors, including the shelduck, mallard and turnstone, are declining, it warned. But the overall number of waterbirds wintering in the UK has doubled since the late 1970s, a report adds. …