Nature World: Bird populations across Europe are on the decline, and have been for the last 30 years, according to researchers, with the majority of losses coming from the continent's most common species. Approximately 421 individual birds have perished in recent decades, 90 percent of them among the most common and widespread species, including house sparrows, skylarks, grey partridges and starlings. "It is very worrying that the most common species of bird are declining rapidly because it is this group of...