Mystery of ‘pekinensis’ Swift migration revealed

Published on 08 June 2015 in News and comment

We normally think of summer migrants in the northern hemisphere heading south to Africa. A few head southeast towards east Africa, but none from the UK venture any further east. We might expect that birds in the Far East would also venture south, but at least three species do not conform, and head westwards for Africa.

The Northern Wheatear Oenanthe oenanthe of Alaska winters in east Africa and the Amur Falcon Falco amurensis winters in southern Africa. Both of these have had their routes revealed by tracking studies using light-level geolocators and satellite tags respectively.

The routes taken by the pekinensis race of Common Swift Apus apus that breeds in Beijing, near the eastern edge of the species’ range, were unknown, but birds of the appearance of pekinensis, and specimens have been recorded in the southwest corner of Africa.

Northern Wheatears, after leaving Alaska, take a northerly route across Siberia, Amur Falcons a more southerly route via India; so which way would the swift go? They also must navigate the Himalayas and the Tibetan Plateau to the west of Beijing.

It was the temptation to solve this remaining puzzle that gave Terry Townshend, founder of Birding Beijing and myself, of Action for Swifts, the idea, at a chance meeting at a BirdLife function, to take up the challenge.

Swift-pekinensis-with-backpack

The idea snowballed with enthusiastic support from the China (Beijing) Birdwatching Society (President Fu Jianping and Professor Zhao Xinru), Beijing Normal University, The Summer Palace, Belgium Ringing Scheme (Lyndon Kearsley) and the CAnMove Group at Lund University (Professor Susanne Ã…kesson).

In May 2014, Lyndon and I flew to Beijing with 31 light-level geolocators from Migrate Technology. Following a training workshop, we arrived at dawn on 24th May at the Kuoro Ting Pavilion in the Summer Palace to meet with the ringing team from the China (Beijing) Birdwatching Society. By 07.30, thanks to their efficiency, we had deployed all 31 geolocators.

A year elapsed and we returned to the Summer Palace, again on 24th May, with another 25 geolocators. We retrapped 13 Swifts with geolocators, the data was downloaded, and the Swifts released for a second year. All 25 new geolocators were deployed on previously ringed birds.

Lyndon Kearsley releasing a 'pekinensis' Swift fitted with a geolocator with Dick Newell in the background recording the moment.

Lyndon Kearsley releasing a ‘pekinensis’ Swift fitted with a geolocator with Dick Newell in the background recording the moment.

An initial analysis confirmed that the first bird went to Namibia, but also that it followed a route that took it WNW out of Beijing, across the Gobi Desert to Mongolia. From there, north of the Tien Shan mountains to the south Caspian, across the Arabian Peninsula then into the Congo, where it stayed for awhile before reaching Namibia. While in the Congo, it would meet up with birds from Europe, which head east or southeast after their stay in the Congo. The return journey to Beijing roughly retraces the steps of the outward journey.

Beijing Swift

The Wheatear may hold the record for the longest migration of a small ‘landbird’, but the swift is not too far behind, with the falcon in third place. I had always been intrigued by the brown Common Swifts that I had seen on Table Mountain; and, interestingly, two of the Swifts reached Cape Town.

Dick Newell

For more pics and a write-up by Terry, visit the Birding Frontiers site, and also the Action for Swifts website