Beijing swifts reveal winter secret

2015-05-29By Yuan Quan

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Bird

Almost all Chinese kids know the rhyme “Little Swift” about the birds that arrive every spring. When asked where the birds come from, parents normally can’t say. But “don’t know” is no longer an answer – at least for the Beijing swifts.

Chinese scientists, bird watchers and environmental NGOs, working with experts from Belgium, the UK and Sweden on a year-long study, discovered that Beijing swifts travel more than 13,000 km. to winter in southern Africa before returning to breed at imperial gardens in China’s capital in the spring and summer.

Data from geolocators fitted to 13 Beijing swifts in May last year showed the birds take a route west-northwest into Mongolia, then south over Iran and the central Arabian Peninsula to tropical Africa, before spending three months of the winter in Namibia and the Western Cape.

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Scientists have mapped out Beijing swift migration route. 

"The migration between China and Africa is unusual among birds,” says Professor Susanne Akesson with the Center for Animal Movement Research at Sweden’s Lund University, "and shows a capacity to explore rich feeding areas far apart for this highly aerial bird species.”

In 1870, the bird was first described by a British naturalist as a subspecies of the common swift, and was named the Beijing swift. Ornithologists see swifts as “supreme aerialists” with very narrow long wings that put them among the fastest animals on the planet. They spend most of their lives in the air and they can feed, drink, mate and sleep on the wing, only landing to breed.

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Terry Townshend releases a swift carrying a geolocator at the Summer Palace on May 24.

"Beijing swifts live on average for seven years, which means the bird in its lifetime will cover a migration distance greater than 182,000 km, about half of the distance from the Earth to the Moon,” says Terry Townshend, a British man who has watched birds in Beijing for four years and founded the Birding Beijing group for fellow enthusiasts.

"Because they seldom land on the ground and they are so fast and so aerial, swifts are very hard to study,” Terry adds.

"The swifts have a special place in the hearts of Beijingers,” says Fu Jianping, president of the China Birdwatching Society.

13 放飞雨燕,放飞鸟类科研与保护的希望-3-张为民 摄影

Bird lovers free the captive swifts at the Summer Palace. 

She remembers the scene 20 years ago when hundreds of Beijing swifts were hovered over the Qianmen Gate Tower, near Tiananmen Square.

The swift has long had a close relationship with people. Zhang Zhengwang, a zoolology professor at Beijing Normal University says: “In ancient times, people forecast weather by its behavior. For example, a swift flying lower meant a storm was coming.”

Ornithologists say the birds like to nest in high buildings with eaves such as city gatehouses and imperial garden buildings. They can be seen at the Forbidden City, the Lama Temple and the Summer Palace from mid-April to July every year.

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People can trace Beijing swifts at imperial gardens where have palace eaves. 

“Their twittering flights at dusk around many of our major landmarks are one of the most enchanting features of our summer,” says Fu.

At 2:30 a.m. on last Sunday, members of China Birdwatching Society, with the help of foreign experts, put up nets around the pavilion where swifts nest at the Summer Palace. They began catching swifts and fitting geolocators to them. They also tried to trap birds fitted with geolocators last year. Within five hours, more than 130 Swifts had been caught, including 13 trapped last year.

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Zhao Xinru, Ornithologist and consultant of China Birdwatching Society, erected nets at a pavilion of the Summer Palace at 2:30 a.m. of May 24 to retrap Beijing swifts.

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Scientists fitted the geolocators to Beijing swifts.

“It will allow scientists to monitor these areas and identify actual and potential threats to the birds’ population,” says Terry.

Ornithologists think the number of swifts in Beijing has declined dramatically.

From 2000 to 2002, Zhang Zhengwang conducted a study at the invitation of a local forest department. He and his team estimated there were only 3,000 swifts in Beijing – far fewer than in 1960s and 1970s.

“The main reason behind the decline is that their breeding sites are greatly reduced,” Zhang says. Most city gatehouses were torn down to make way for tower blocks and wide roads. Nets have been erected nets on many ancient buildings in order to prevent corrosion from bird waste.

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Chinese and foreign birding experts work together to analyse the data from the geoloacators. They will use the data to contact scientists in southern Africa to monitor, and look out for the Swifts in the northern winter.

Fu noted that some  modern buildings imitate the eaves of ancient architectur, which attract swifts back to nest.

"In Beijing we can begin to have conversations with building developers to explore whether we can make new buildings more ‘swift-friendly’ by including nesting places in the design,” says Terry.

Although there is no recent official data to show the decline, scientists believe the number is dropping due to the deteriorating environment and increasingly serious air pollution.

China Bird Watching Society has banded swifts with metal rings for seven years. According to Fu, the bands show the longevity of swifts and their loyalty to breeding locations, but offer no information about the location of wintering grounds or the migration route.

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China bird watching organizations used to banding the swifts with metal rings. 

"For years we have waved them goodbye at the end of July not knowing where they go,” says Fu. “We could only speculate about their journey.” 

(All pictures provided to Icrosschina were taken by Zhang Weimin with China Bird Watching Society )

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