Satellite-tagging on the edge – 1st report 2018: Connecting NW Australian Red Knots to their staging sites

Eva Kok (Royal NIOZ and PhD student at the University of Groningen) reports about satellite-tagging Red Knots in two major wintering areas of the East Asian–Australasian Flyway in NW Australia: Roebuck Bay and Eighty Mile Beach. In February 2018, she worked there together with team leader Chris Hassell (GNF Australia) and PhD student Drew Bingrun Zhu, and was supported by the AWSG, Ying Chi Chan and Lee Tibbitts.

“It has been more than two months since the NWA expedition 2018. More than ever it was an expedition full of challenges, mainly due the arrival of cyclone Kelvin. After a lot of rain, and waiting, we were eventually successful in catching and equipping 2 gram satellite PTTs on Red Knots using the full body harness. In the past two months we have been excitedly following the movements of these birds.

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A Red Knot with colour-rings and a 2 gram satellite PTT, held by Eva Kok. Photo: Drew Bingrun

We caught the Red Knots well in advance of the expected migration to the breeding grounds to give them time to adjust to wearing the tiny tracker and gain sufficient amounts of energy stores to take on the long-distance flight north. According to expectation, the first few weeks were characterized by short-distance movements on the mudflats between foraging grounds and high tide roosts.

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Red Knots on Eighty Mile Beach, just released after being equipped with a 2 gram satellite PTT Photo: Drew Bingrun

The first movements happened in the first week of April when two birds, who were caught on Eighty Mile Beach (80MB) before the cyclone hit us, moved up to Broome and mingled with the tagged birds that we caught later in Broome. This is a regular movement, and the birds settled on the mudflats of Broome where Chris and Kerry saw the knots growing fat (see picture below).

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Satellite-tagged Red Knots “hanging out” and getting fat on the beach of Roebuck Bay. Photo: Kerry Hadley

On 25 April our wait was finally rewarded when the first bird, caught at Roebuck Bay on 18 March, finally decided to cross the Timor Sea to fly to Borneo. For a moment we thought this was the signal for migration to start, but in the meantime the other birds did not show any sign of migratory movement, and the days passed by.

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On 25 April 2018, the first Red Knot crossed the Timor Sea to fly towards Borneo

Eventually the real wave of departure started almost three weeks later! Then six other Red Knots exchanged the mudflats of Broome for the mudflats in Indonesia and the Philippines. On 22 May 2018 already two Red Knots had reached China and we can’t wait for them to show us where they will go next to breed.”

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Tracks on 22 May 2018. Two Red Knots in Bohai: one still in Nanpu and one north in Yingkou. Three birds at S China coast: near Wenzhou, Zheijang , near Fuzhou, Fujian, and near Macau/Hong Kong. Also note the birds still in Borneo and Vietnam.

Video by Drew Bingrun: Eva Kok and Chris Hassell releasing satellite-tagged Red Knots.

 

Acknowledgements

The field work in NW Australia in February 2018 that made it possible for us to successfully deploy Red Knots with solar-panelled satellite-transmitters was funded by the MAVA foundation. We want to thank the members of the expedition of the Australasian Wader Studies Group (AWSG) for their help and support in the field.

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