YAKUTSK, May 4. /TASS/. A public network to monitor the migration of Siberian crane's East Siberian population (white crane) was organized in Yakutia to assist in preservation of the endangered species, a fellow at the Institute for Biological Problems of Cryolithozone (the Russian Academy of Sciences' Siberian Branch) and at the Kytalyk National Park, Mariya Vladimirtseva, told TASS.
Siberian crane is the world's third most rare crane species. The birds nest only in Russia. They have two disparate populations - the West Siberian (Ob) and the East Siberian (Yakut). The East Siberian population has grown to about 5,500 birds over recent decades, though it still remains critically low for the species' long-term survival. For comparison: the world's population of gray crane, also listed in Yakutia's Red Data Book, is at least 300-400 thousand birds.
"During the mass flight of cranes in May, we ask Yakutia's residents to report all occasions they see migrating birds. The public monitoring network is [extended to] Yakutia's seven districts along the migration route. People are sending to us photos and videos of white crane flocks. At times, even experienced observers can confuse flying Siberian cranes with gray cranes. We anyway are very grateful for records of migrating gray cranes," the expert said.
"We gratefully accept these records, as they are of scientific interest to us. Our years-long database keeps all these records and their authors. We use these records to analyze the ecosystems, to locate where the migrating birds make stops, to see whether they are safe," the expert added.
The scientists use the data to offer the best conservation strategy, she said.
Nesting conditions
The key measure to preserve the Siberian crane population in Yakutia is to maintain a high level of conservation work at nature reserves and parks, along the migration routes and in places where the birds make stops, and where they are nesting. The region has been creating new nature reserves. "The population preservation is impossible without scientific research to be used for most effective strategic solutions," the scientist said.
Protection measures also include the eco-education of local people. Scientists may insist certain activities near nesting sites be replaced. Experts also use space monitoring opportunities.
The breeding success depends strongly on weather and climate conditions in the north of Yakutia. In order to incubate, a pair of birds has to find a place on the nesting site, which is free of snow. If the previous year's nest is free of snow, they will occupy it so that not to waste energy and resources. "Generally speaking, the weather conditions in 2022 were not unfavorable: most pairs, monitored there, had chicks in July, each couple had one chick," she told TASS.
Siberian cranes lay one or two eggs, but afterwards, in most cases, a pair has only one chick. Scientists explain it by the so-called chick aggression: the younger chick cannot withstand the elder's pushing.
"The chick aggression is observed in several species of cranes, and in Siberian cranes it is top high. However, sometimes parents manage to keep both chicks. In such cases, the male cares for one of them, and the female - for the other. Scientists have received proofs that sometimes both chicks survived since the first ringing in Yakutia in the early 1990s. Since 2019, we have registered two families of the kind," she continued, stressing the male and the female bear equal responsibilities in incubating and raising.
Wintering
In autumn, Siberian cranes migrate across Yakutia, stopping to rest in river valleys, on river islands and scythes, near lakes. The East Siberian population inhabits the low-lying tundra between the Yana and the Kolyma Rivers in the north of Yakutia.
The birds are flying away to spend winter in southeastern China, on Lake Poyang in the Yangtze River basin. The Poyang Lake Nature Reserve in Jiangxi Province is an important wintering site both for cranes and for other wetland birds. In 2022-2023, more than 700,000 birds stayed there in winter.
The summer of 2022 in China was incredibly hot, and Lake Poyang suffered a severe drought. White cranes' main food in winter is eelgrass (vallisneria), an aquatic plant, which survived only in a very small part of the lake, where water still remained.
"Scientists and the nature reserve personnel, supported by the state, refilled water, and organized 12 feeding points with rice plantings. The cranes also could feed on lotus fields, which were specially maintained for them. Without that assistance, it would have been very difficult for the white cranes to survive the past winter," the scientist said.
According to Chinese experts, due to extremely high temperatures and dry weather in the autumn of 2022, migrating birds flew to the wintering sites earlier than usual. The spring migration in 2023 was also delayed as the birds needed to gain energy necessary for a long flight back.