Knowledge gained from tracking a migratory bird boosts its protection

By Ji Jing
0 Comment(s)Print E-mail Beijing Review, April 23, 2021
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Crested ibises soar over a field in Yangxian, a county in Shaanxi Province, on January 28. [Photo/Xinhua]

During the Beijing summer, people used to see and hear flocks of Beijing swifts circling around the city's historical places such as the Summer Palace and the Temple of Heaven.

The Beijing swift is a typical cavity-nesting bird that often nests inside the holes and crevices in old constructions.

The bird, a subspecies of the common swift, named after the city of Beijing, was first recorded in China's capital by British naturalist Robert Swinhoe back in 1870.

Every spring, the swifts return to Beijing to breed, and then, at the beginning of every autumn, they head down south to their wintering grounds once again.

Tagging the bird

Where do these migratory birds come from and where do they go for winter? These questions had puzzled bird lovers and researchers alike, until answers came trickling in recently.

The Beijing Bird Watching Society, now known as the China Bird Watching Society, launched the Beijing Swift Project in 2014 to track the birds for their better protection.

In the past decades, the number of this species declined sharply, from tens of thousands in the early 20th century to around 3,000 at the beginning of this century.

"The Beijing swift is an insectivorous bird that is sensitive to changes in the environment," Zhao Xinru, an ornithology expert from Beijing Normal University and chief director of the project, told The Beijing News. "To protect them, we need to study their migration routes, find out where they spend the winter and measure their flying speeds," he added.

Since 2007, the Beijing Bird Watching Society has started banding the Beijing swifts at the Bafang Pavilion, a double-eave octagonal pavilion inside the Summer Palace.

Bird banding, or bird ringing, is one of the oldest and most important techniques used for the study and identification of individual birds as well as an important method to track their migration. It involves attaching a small colored tag to the leg of a bird—each one with a unique code on it. Zhao first adopted the practice in 1983. He said that in China, bird banding usually entails the attachment of a metal ring to a bird's foot. "The thickness and length of a bird's foot is not affected by the changes of its weight or age," Zhao said.

Each metal ring has a serial number engraved on it so people who discover the bird can subsequently report its location and the date of detection to the bird banding institutes which will then upload these data onto a shared platform. The more locations reported, the more accurate the study will be.

Nevertheless, the practice of bird banding does come with its limitations as the data are unstable and it relies solely on those who detect the birds along their flight routes. As a result, the Beijing Swift Project opted for geolocators to track the birds.

"The data collected using bird banding over one century may be less than those collected via geolocators in one year," Zhao said.

The project selected a type of geolocators produced by UK company Migrate Technology. Each geolocator costs around 1,300 yuan ($199) and weighs only 0.65 grams, meeting the international rule that the equipment attached to a bird should remain under 3 percent of its bodyweight so that it will not affect its survival. A Beijing swift weighs between 31 to 41 grams.

Terry Townshend, a British ornithologist who has been active in the field of bird protection in China for nearly 10 years, recalled that the project team chose to net the birds at the Bafang Pavilion to install the geolocators because it housed the largest number of Beijing swift nests in the capital city. It's estimated there are 50 to 100 nests there and, given the Beijing swift's monogamous lifestyle, there are usually two grown-up birds per nest.

On the morning of May 24, 2014, eight soft nets were put up inside the pavilion before 4 a.m. as the Beijing swifts would leave their nests around that time.

Researchers then managed to arrest over 100 Beijing swifts. They attached rings to those that had not been banded before and attached geolocators to those that had been banded and were in good condition as these birds were more likely to return.

Unlike GPS geolocators attached to large birds, the low energy consumption photosensitive geolocator is unable to send out a message on the bird's real-time location. Researchers can only download the data after they catch the birds again.

However, the advantage of using such locators is that they are cheaper and have light batteries, and hence more suitable for small birds.

Ambassador for ecological cooperation

One year later, on May 24, 2015, 13 Beijing swifts carrying geolocators were caught again.

Researchers downloaded the data from the geolocators and found the birds had traveled nearly 30,000 km across 19 countries and regions.

The data showed that after flying out of Beijing, the birds had flown past Inner Mongolia Autonomous Region, the northern side of Tianshan Mountains in Xinjiang Uygur Autonomous Region, Central Asia, the Arabian Peninsula and Central Africa before arriving in the southwest of Africa by late October. They spent the following three months in Namibia, Botswana and the Western Cape Province in South Africa and once again set course for Beijing the following February, touching down in China's capital in April.

Zhao added tracking the migration routes of the Beijing swift serves the species' better protection as research is a prerequisite for protection.

Another factor for consideration is the environment of the countries and regions that the birds pass through, including risks such as food shortages, hunting, etc.

Since 2014, researchers have attached geolocators to 66 Beijing swifts and reclaimed 25 of them.

The good news is that as of late June last year, the number of Beijing swifts had increased to over 6,000.

In recent years, Beijing's air quality has noticeably improved. "The number of days featuring good air quality has risen, which also helps to preserve the bird," Zhao said.

"Increasing the area of green space and restoring wetlands can increase the amount of insects and thus provide more food sources for insectivorous birds. The gardening and greening authorities of Beijing have been advocating the use of fewer pesticides, effectively preventing the accumulation of poison in insects and hence saving birds from being poisoned," Zhao added.

However, learning about the migration routes of the Beijing swift is only the first step towards their overall protection.

Next, the project's experts and volunteers hope to strengthen international cooperation to ensure the migration routes of the birds are safe.

Townshend has suggested the government make the Beijing swift an ambassador for enhancing ecological protection cooperation among Belt and Road countries as half of the species' migration routes pass through their skies.

Moreover, the Beijing swifts themselves are also adapting to changes. Zhao said as much of the city's old architecture was demolished in the process of urban development, more and more Beijing swifts have found new habitats such as the overpass crevices.

"They are learning to adapt to the changes of the city and this proves that they are not as fragile as we previously believed," Zhao said.

Better protection

China has stepped up bird protection in recent years by creating nature reserves and cracking down on the illegal shooting of wild birds.

According to statistics from the National Forestry and Grassland Administration (NFGA) in April 2020, China counted 1,445 bird species, accounting for one sixth of the world's total and making it the country with the most bird species in the world.

Since 1981, China has been hosting the Bird Week every spring to increase awareness of and participation in the protection of human's feathered friends.

On April 13, commemorative activities for the 40th anniversary of the Bird Week took place at the Beijing Botanical Garden. The Beijing Gardening and Greening Bureau released a catalogue documenting the wild birds of Beijing, showing there are 503 species of wild birds roaming the capital city.

In addition to protecting birds in their natural habitats, China has also strengthened the protection of endangered bird species through artificial breeding.

The NFGA announced at the ceremony that over the past 40 years, the number of crested ibises has increased from a mere seven to over 5,000, the number of white cranes from 210 to over 4,500 and the number of black-faced spoonbills from 1,000 to over 4,000.

Spring is a critical time for bird reproduction and a primary season for mass migration and the gathering of birds. Consequently, this is a crucial time for migratory bird protection.

The NFGA hosted a teleconference on March 26 regarding migratory bird protection.

It requires local forestry and grassland departments to fully understand the routes of migratory birds through close monitoring and observation, clear bird nets and traps and prohibit hunting of these birds.

Next, the NFGA will improve laws and regulations as well as strengthen law enforcement to improve bird protection.

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