Many common species of birds are in decline worldwide because of deforestation, the rapid growth of industrial-scale agriculture and fishing, the spread of invasive bird species, and hunting, according to a new report from the U.K.-based conservation group, Birdlife International. In its report “State of the World’s Birds,” the group said that in the past quarter-century, nearly half of Europe’s most common birds — including turtle doves, grey partridges, and corn buntings — had declined, some by as much as 80 percent. Numbers of twenty common American birds, including the bobwhite quail, have dropped by more than 50 percent in the past 40 years, and in Asia species such as white-rumped vultures — which once numbered in the millions — are nearly extinct. Industrial-scale fishing fleets, which use countless baited hooks on long lines, have sharply reduced the number of some seabirds, including albatrosses, the report said. “Birds provide an accurate and easy to read environmental barometer, allowing us to see clearly the pressures our current way of life are putting on the world’s biodiversity,” said Mike Rands, Birdlife’s CEO.