Migratory birds travel vast distances across continents and oceans while demonstrating amazing feats of endurance. Once a year, a shorebird called the bar-tailed godwit (pictured below) flies more than 10,000 kilometers (6,200 miles) – nonstop – from its nesting site in Alaska to its wintering grounds in New Zealand. Meanwhile, over the course of its lifetime, an Arctic tern will fly the equivalent of the distance to the Moon and back three times. But more than half of the migratory birds across all major flyways have declined over the past three decades. According to new findings published in Science this week, only 9 percent of migratory birds receive adequate protection across their entire range.
Animals who migrate depend on a suite of interconnected sites for breeding, eating, and resting, to refuel along the way. And in each of these locations, they play major roles in processes like predator-prey interactions, biomass transfer, and nutrient transport. Yet we’re still unclear about how well they’re actually protected. So, a team led by Claire Runge from the University of Queensland mapped out the migratory routes of 1,451 species to measure the distribution of protected areas for migratory birds around the world.
"If a species has adequate protection in one part of their range, let’s say one country has all their breeding grounds, but they are missing protection in a different part of their range, let’s say another country has all their stopover sites, this is bad," Runge tells IFLScience. "They can decline or even go extinct, because the whole population uses both these areas at some point in time.”
They found that 91 percent of migratory bird species are inadequately covered by protected areas for at least one part of their migration pathway. For comparison, 55 percent of non-migratory species have inadequate protected area coverage.
Bar-tailed godwits (Limosa lapponica) resting after undertaking one of the longest endurance flights in the world. Dirk Hovorka
Eighteen species aren’t protected in their breeding areas, and two species don’t have any protection along their route at all. What’s worse, less than 3 percent of threatened migratory birds are sufficiently protected across their yearly cycle. For example, less than 4 percent of the distribution of a vulnerable parrot called the red-spectacled amazon occurs within protected areas.
The team also examined 8,283 sites identified as Important Bird and Biodiversity Areas (IBAs) – where migratory birds congregate in high numbers or where populations of threatened migrant species are supported. The IBAs of only 2.9 percent of migratory birds are fully protected across each of their seasonal areas.
Differences in protection levels vary between countries – though those in North Africa and Central Asia appear to offer the least protection. Germany, for example, meets the target for protected area coverage for 98 percent of the migratory birds within its borders, but less than 13 percent of the country’s migrants are adequately protected elsewhere. And it doesn’t seem to be a matter of wealth: Many Central American countries meet the targets for more than 75 percent of their migratory species, which have lower levels of protection in the U.S. and Canada. Better-targeted investment and better coordination among countries, the authors write, are needed to conserve species throughout their migratory cycle.