资源环境科技发展态势分析平台

Danny Green / naturepl.com

By Andy Coghlan

1469 bird species are threatened with extinction, warns a global report. That is around one-eighth of the 10,966 known species.

Farming is the biggest single threat. 74 per cent of the threatened birds – 1091 species – are in trouble because of expansion and intensification of farming. This is true of tropical species in South America and farmland birds in Europe such as skylarks, lapwings and corn buntings.

The 2018 State of the World’s Birds report was released on Monday by BirdLife International at a conference on bird migration.

It reveals that farms now occupy six times more of Earth’s land surface than they did 300 years ago, rising from 6 to 38 per cent between 1700 and today.

Falling birds

“It’s being driven by changing human consumption patterns, especially an increasing switch to a high-meat diet,” says lead author Tris Allinson of Birdlife International. “Today, two-and-a-half times more people are overweight than undernourished, and average daily protein consumption is a third higher than needed.”

The growth of agriculture is destroying birds’ habitat. In the tropics, the problem is that farms are spreading out onto ever more land “to grow things like cocoa, sugar, soya, coffee and palm oil that’s driving the loss of habitat,” says Allinson. “In the developed world, it’s the intensification that’s the problem.”

This loss of habitat is even putting pressure on relatively common species, like turtle doves in Europe and Asia and grey parrots in Africa. “The trend we’re really noticing is seeing more familiar, widespread species in trouble,” says Allinson.

The loss of land is being compounded by other disruptive human activities, like logging and draining of wetlands. “Logging is often the precursor to turning over land to farmers,” says Allinson.

A rescue plan

Hunting is also putting pressure on 517 threatened species. For example, the yellow-breasted bunting was classed as “least concern” 15 years ago but is now “critically endangered”. Thousands are illegally caught, killed and eaten as delicacies in Asia, especially China. Every year an estimated 12 to 38 million migratory songbirds, such as blackcaps, meet the same end in the Mediterranean.

Climate change is a threat to 485 species. They include snowy owls, which are classed as “vulnerable”: their snowy habitat is shrinking because the Arctic tundra is warming rapidly.

Allinson says we can save many of the threatened birds. “We do know how to restore degraded ecosystems, and we can farm more sustainably,” he says. “The solutions are there.”