Team learns lessons from death of 'Hope'

Since 2013, when they began a project that uses satellite tracking to trace the migration routes of the white-naped crane's western population, Jia Yifei, a researcher with Beijing Forestry University's Center for East Asian-Australasian Flyway Studies, and his students and research partners have fitted small devices on more than 70 cranes.

"Once fitted with a satellite device, and without any incidents, a crane can provide its migration data to us for four to five years," Jia said. "Then the device becomes dysfunctional and we lose track of the bird."

With so many birds fitted with the devices, tracked and then disappearing, Jia has no specific impression of any individuals, apart from one they named "Hope".

Jia and his colleagues first installed tracking devices on six white-naped cranes in 2013. They named them "Hope" in Chinese, English, Mongolian, Japanese, Korean and Russian, in the expectation they could bring some hope to reversing the decline of the wintering population in China.

One Hope, an adult individual, had a smooth first year with the tracking device. It migrated to Poyang Lake for wintering and returned to its breeding grounds in Mongolia in the spring of 2014.

In the fall of 2014, the researchers found it had returned to Chinese territory, arriving at the Shandian River Basin in Duolun county, Inner Mongolia autonomous region, on Oct 12 and leaving on Oct 26. During the staging period, Jia and his teammates conducted field investigations and took a photo of the bird.

They then returned to Beijing, but Jia kept an eye on Hope's whereabouts.

On Oct 27, 2014, the bird arrived in Yanggu county, Shandong province. "We found that it was flying toward a location in the city, but the signal was lagging, making it difficult to confirm," Jia said. The next day, they confirmed the signal was coming from the city.

At the same time, a manager at a zoo in Yanggu contacted one of Jia's research partners and said local residents had found several white-naped cranes that appeared to have been poisoned. One was fitted with a satellite tracking device.

Jia and his teammates rushed to Yanggu and discovered that the cranes, including Hope, had eaten some winter wheat seeds that had been soaked in pesticide.

It was a common practice in northern China, Jia said. In autumn, winter wheat is planted on the North China Plain. In winter, the seedlings are covered by heavy snow and will grow well the following year. But when farmers sow the seeds, they soak them in chemical pesticides to protect them from pests.

The cranes, however, were clever enough to dig up and eat the winter wheat seeds. As a result, they ended up getting poisoned.

After Jia and his colleagues arrived in Yanggu, they treated the birds by giving them enough water to drink and maintaining their physical condition to aid detoxification.

"After Hope and the other birds recovered, we released them on Nov 11, 2014," Jia said.

Everything was fine with the bird, and in the spring of 2015, Hope had returned to Duolun from Poyang Lake. "We were happy to see the bird again," he said.

But when Hope's signal stopped moving, the researchers located the bird, which had died.

They took the crane back to their laboratory at Beijing Forestry University to discover why it died.

After removing part of its gullet, they found it was filled with crops grown in the area — mainly buckwheat.

The crane's body was relatively strong and bulky, indicating that it had not died of starvation, Jia said, but it did have a slight external injury.

"But we were not sure if it was an injury caused by some animal's attack or if it occurred after its death when other animals scavenged its body," Jia said. "It remains a mystery."

One thing he is sure of is that the staging site of the white-naped cranes in the area is mainly farmland, meaning the birds live close to all kinds of human activities.

"Sometimes it's too close," Jia said. "Even home cats or stray dogs might become a threat to their survival."