Out Of Africa! The Beijing Swift’s Incredible Journey Charted At Last
A ground-breaking study has revealed that the Beijing Swifts1 which breed at The Summer Palace in Beijing, travel more than 13,000km to spend the winter in southern Africa before returning the following Spring. This means that, in its lifetime, the average Beijing Swift will cover a migration distance greater than 180,000 km, about half of the distance from Earth to the Moon. These iconic birds - synonymous with Beijing since 1417 when they made their nests in the original city gatehouses - arrive in Beijing in April and, after breeding, begin their long journey to Africa in late July, taking a route that first leads them west-northwest into Mongolia, from where they pass north of the Tianshan mountains, then south through Iran and central Arabia into tropical Africa, before spending 3 months of the winter in Namibia and the Western Cape They begin the return journey in February, retracing a similar route, arriving in Beijing in mid-April, a journey that sees them cross about 20 borders. The project, a collaboration between scientists from Beijing and Guangzhou in China, Belgium, Sweden and the UK, began in May 2014 when ultra-lightweight ‘backpacks’ containing tiny light sensing geolocators were fitted to 31 Beijing Swifts as part of an ongoing banding operation by the China Birdwatching Society at The Summer Palace. The geolocators, generously provided by scientists in Sweden and the UK, log the position of the Swift by measuring day length and local midday from which positions are calculated. When the Swift is recaptured, one year later, the data is downloaded and analysed using special software. Until now there was only speculation about the journeys made by one of Beijing’s iconic birds. For the first time we know the distance travelled, the route taken and wintering areas used by an individual bird. As in many other parts of the world, Swifts in Beijing have declined dramatically (60 per cent in the last 30 years, according to a Beijing Professor). Understanding their movements will help scientists and conservationists to discover the reasons for the decline and to put in place measures to help them.
Background About Swifts
The east Asian subspecies of Common Swift (Apus apus pekinensis) arrives in Beijing in April and, after rearing young, most have left the capital by the end of July. Until now there was only speculation about where they spent the other 8 months of the year. Supreme aerialists, Swifts spend almost all their life in the air, a lot of that at low level, feeding on airborne insects. If they need to, Swifts can fly very high; they have been observed migrating at 18,700 feet (5,700 metres) over Ladakh in the Himalayas. Some species of swift are among the fastest animals on the planet, with some of the fastest measured flight speeds in active flapping flight of any bird. The top speed recorded in a recent scientific study was 111.6km/h (69.3mph)! Swifts feed, drink, mate and sleep on the wing, and only land
to breed. So a young Swift will spend its first two or three years in constant flight before it nests. Because they never land on the ground, and are so fast and so totally aerial, Swifts are very hard to study. There's still a lot that we don't know about them. Swifts eat billions of harmful insects every single day. Swifts are fun - they enhance our lives with their dramatic flight and exciting calls.
About The Project
Since 2007 The China Biodiversity Conservation and Green Development Foundation Birdwatching Society (formerly The Beijing Birdwatching Society) has been banding Swifts (Apus apus pekinensis) at The Summer Palace. This banding has revealed important information about the longevity of Swifts and their loyalty to breeding sites; re-trapping has shown that most Swifts return to the same breeding location every year. However, this work has not revealed any information about the location of the wintering grounds or the migration route. Following successful projects to fit geolocators to Common Swifts in Europe and the generous support of Susanne Åkesson at the University of Lund in Sweden, and Dick Newell, of Action for Swifts in the UK, a project was developed to fit geolocators to some of Beijing’s Swifts. In May 2014, 31 geolocators were fitted to Swifts caught at The Summer Palace in an operation led by veteran Swift bander, Lyndon Kearsley. These tiny ultra-lightweight ‘backpacks’ record the location of the Swift by measuring light level and time every minute resulting in daily positions, which are stored in the memory of the device. Retrapping of the birds allows the data to be downloaded for analysis. Given the site loyalty, proven by the work of the Beijing Birdwatching Society, the scientists knew that there was a very high chance that the birds carrying geolocators could be retrapped at the same site a year later. On 24 May 2015 nets were erected to catch Swifts at the same pavilion at the Summer Palace and 13 birds carrying geolocators were retrapped, allowing the data to be downloaded and analysed. The initial results presented here are part of an ongoing project to find out more about the migration patterns of Beijing’s (and east Asia’s) Swifts. Understanding their movements will help scientists and conservationists to discover the reasons for their dramatic decline and to put in place measures to help them.
Note: A comprehensive analysis of the data from all recaptured geolocators in May 2015 will be published in due course in a full scientific article.
Many thanks to Zhang Weimin for allowing us to use this information