Hunting threatens one of the world's largest bird migrations

Researchers say the study suggests the birds that make up one of the world's largest migration corridors are more vulnerable that previously thought.

"The Asia-Pacific is host to one of the most amazing animal migrations on earth," lead study author Eduardo Gallo-Cajiao, doctoral student at the University of Queensland in Australia, said in a news release.

"Every year, hundreds of thousands of shorebirds, wetland-dependent species, breed across the Arctic and boreal regions, moving south to Southeast Asia, Australia, and New Zealand along a migration corridor known as the East Asian-Australasian Flyway," Gallo-Cajiao said.

At least 61 migratory shorebird species use the East Asian-Australasian Flyway, trekking more than 15,000 miles each year. Unfortunately, the numbers of several of the corridor's signature species have been declining over the last few decades and a few species are close to extinction.

Conservationists and bird researchers have mostly blamed human development -- and the habitat loss and pollution that comes with it -- for the decline, but the latest research, published this week in the journal Biological Conservation, suggests illegal hunting has made things worse.

"The scale and significance of hunting was unknown prior to this study, and it's clear that it's likely contributed to declines of migratory shorebirds in this region," Gallo-Cajiao said.

To gauge the risks facing birds traveling on the East Asian-Australasian Flyway, researchers surveyed hunting records for 46 species in 14 countries across the Asia-Pacific region. The data showed several vulnerable species -- including the spoon-billed sandpiper, of which there are less than 500 left -- face hunting threats on the route along the flyway.

"Our study discovered that other threatened species that have been subject to hunting include the great knot, far eastern curlew, and spotted greenshank," Gallo-Cajiao said.

Researchers hope their study will encourage more robust protections for the most vulnerable species. Because the East Asian-Australasian Flyway spans so many different countries, the protection of vulnerable shorebirds will require increased international cooperation.

"There's no coordinated monitoring of how many shorebirds are taken annually across the region, which makes management really hard," Gallo-Cajiao said. "Internationally coordinated approaches to address hunting are now underway, including through the UN Convention on Migratory Species, but these efforts need to be drastically ramped up to avoid extinctions and maintain healthy wildlife populations.

"Additional ground surveys and an international coordinated monitoring strategy are also urgently needed," Gallo-Cajiao added.