Dozens of what were once numbered among the world's most common birds have suffered disastrous slumps in numbers in the past half century, a report has concluded.
Population crashes of birds such as cuckoos and nightingales in Britain have been matched by equally sharp falls in the numbers of species well known in other parts of the world.
While in Britain and parts of Europe familiar species such as the turtle dove and corn bunting have declined dramatically, in North America the northern bobwhite has done so.
In Asia the same fate has befallen the white-rumped vulture, and in the Middle East the Eurasian eagle owl is also vanishing.
The findings are in a report called State of the World's Birds, published Monday at a world conference in Buenos Aires held by BirdLife International, an alliance of conservation groups.
"Many of these birds have been a familiar part of our everyday lives, and people who would not necessarily have noticed other environmental indicators have seen their numbers slipping away, and are wondering why," said Dr Mike Rands, chief executive of BirdLife.