Female leatherback turtles are among the most intrepid creatures in the world, making journeys of up to 10,000 miles after nesting to find food in distant seas. They are known to range from tropical Southeast Asia to the cold waters of Alaska, where jellyfish are abundant.
But traveling that far means encountering threats that can be fatal: fishing nets meant for other species, poachers, pollution and waters warmed by the climate crisis, which force turtles to travel even further to find their prey.
These turtles are just one of hundreds of migratory species – those that make remarkable journeys every year across land, rivers and oceans – that are at risk of extinction due to human interference, according to a landmark report from the UN agency. published on Monday.
Of the 1,189 creatures listed by the Convention on the Conservation of Migratory Species of Wild Animals, or CMS, more than one in five are threatened.
They include species from all types of animal groups – whales, sharks, elephants, wild cats, birds of prey, birds and insects, among others.
About 44% of listed species are experiencing population declines, the report said. Most alarming is the state of the world’s migratory fish: almost all, 97%, of the fish listed are threatened with extinction.
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Migratory species include some of the most iconic animals on the planet, such as elephants. These elephants are grazing after sprinkling sand on their bodies at Kimana Sanctuary in Kimana, Kenya – a mud bath that helps protect them from heat and insect bites.
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Baby sea turtles head out to sea at sunset on Lhoknga Beach, Indonesia, in February 2023.
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Scalloped hammerhead sharks swim near the Galápagos Islands. Almost all of the migratory fish mentioned in the report are threatened with extinction.
The report is the first inventory to assess the status of migratory species and how they are trying to survive in a world dramatically changed by humans. It concluded that the two biggest threats were overexploitation and habitat loss due to human activity, such as the clearing of land for agriculture, roads and infrastructure. These activities also fragment the routes of migratory species, sometimes making it impossible for them to complete their journey.
About 58% of monitored sites recognized as important for migratory species face what CMS considers unsustainable levels of human pressure.
Climate change and pollution are also important threats. Warmer temperatures not only force some species to travel further, but can also cause animals to move at different times of the year. This could mean losing prey or a breeding mate.
A particularly striking example is the narwhal. These mythical-looking sea creatures, famous for their spiral tusks, spend summers in nearly ice-free coastal areas before migrating south to the deeper waters of the Arctic.
However, as oceans warm and the annual expansion of sea ice happens later and later, scientists have found that some narwhals are delaying their journey, risking becoming trapped in sea ice without breathing holes. if flash ice freezes in the fall.
A female narwhal appears in an area of open ocean surrounded by sea ice near west Greenland. As oceans warm and the annual expansion of sea ice is delayed, narwhals are threatened by flash freezes, which can trap them underwater with no open ocean to breathe.
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A colony of gray-headed albatrosses in Elsehul, South Georgia. According to the report, these bird species are threatened mainly due to bycatch in longline fishing.
Global warming can also cause the destruction of habitats such as coral reefs for sea creatures.
Light pollution is also making migration more dangerous for some species, especially birds. At the McCormick Place Lakeside Center, a Chicago building on the shores of Lake Michigan, more than 40,000 dead birds have been recovered since 1978, the report noted, having collided with them after being attracted to the light streaming from their windows.
Some mass whale strandings have been linked to noise pollution, while plastic pollution has been linked to the mortality of albatrosses, large migratory seabirds.
The report illuminates how the creatures that make these often spectacular journeys also play a vital role in maintaining Earth’s delicate ecological balance.
“These animals are, first and foremost, part of the ecosystems where they are found,” CMS Executive Secretary Amy Fraenkel told CNN. “And we have a lot of evidence that shows that if we remove these species, if they decline, it will have impacts on the ecosystems where they are found, and not in a positive way.”
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Migratory bats act as pollinators of more than 500 species of flowering plants, the report states.
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Birds also have cultural importance for some communities. In Asia, for example, the black-necked crane is a sacred symbol in Buddhist culture.
Take bats, for example. It can be difficult to think of them as creatures who make the world a more beautiful place. But those that migrate play a crucial role as pollinators of a huge variety of fruits and flowers – they pollinate more than 500 species of flowering plants, the report says.
Bats disperse seeds, which help maintain healthy forests, and regulate the spread of insects by consuming large quantities of them.
But bats are threatened by deforestation, which destroys their habitat, as well as by hunting – their meat is considered a delicacy in some countries. Noise pollution also distracts bats from searching for food, making them less efficient hunters.
There is good news in the report. There are 14 species that have recorded positive trends, including blue whales and humpbacks. But overall, the picture is alarming.
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Although the population of the iconic humpback whale has increased after centuries of hunting, the report calls for strong conservation efforts worldwide.
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For African wild dogs, climate change is a fundamental threat. Extreme heat causes them to forage for less food and raise fewer young.
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Gazelles with goiter, or black-tailed gazelles, on a hillside in the Gobi Desert in southern Mongolia. Increased road traffic and industrial development restrict their long-range movement.
“Today’s report clearly shows us that unsustainable human activities are endangering the future of migratory species – creatures that not only act as indicators of environmental change, but also play a key role in maintaining function and resilience of our planet’s complex ecosystems,” Inger Andersen, executive director of the United Nations Environment Programme, said in a statement.
The report was launched Monday at a major UN conference on wildlife conservation in Samarkand, Uzbekistan.
Reducing threats to migratory species will require global efforts, experts say, as many animals that make these regular journeys cross international borders, whether on land, sea or in the sky.
“Migratory species have a special role in nature because they do not recognize political boundaries,” said Anurag Agrawal, professor of environmental studies at Cornell University. “Instead, they unite large areas of the planet through their movements. Its conservation therefore requires international cooperation.”