Monday, 6 August 2018

Satellite tagged Eurasian Whimbrels and Grey-tailed Tattler; Australia Wader Study Group - Start heading south

It has been about 9 weeks since our satellite tagged Whimbrels and Tattlers arrived the breeding ground, happy to see that they are now on their way back south!

Satellite tagged Whimbrel 2017:

KU seems to have had a successful breeding season in the Arctic. It’s breeding location is the same as in 2017 at Sakha Republic, about 140km south of Yana Bay. Based on KU’s track since 1-Jun, it apparently nested at almost the same location as the previous breeding season, only 1.4km east from last year!

Fig 1: KU’s breeding location

Fig 2: KU’s nesting location in 2017 and 2018

After 62 days mostly without moving more than 5km away from its nest, KU decided to depart Siberia on 2-Aug, which is the same date as last year. It made a direct flight >3,400km to Yingkou in Liaoning Province at the Yellow Sea with an amazing average speed over 70km! The area where KU landed is again very close to where it spent 49 days stopping over in 2017 southward migration. Let’s see if KU is going to do the same this year.

Fig 3: First leg of KU’s southward migration this year.

Third-year Whimbrel LA, however, didn’t seem to have bred this year. After arriving in Chukotka on 8-Jun, it has been in three different locations covering 110km along the base of a mountain range. It was not in any of these locations long enough for nesting before it moved to the 4th location near the Chukotka-Sakha border.

Fig 4: LA’s migration from China to Russia

Same as KU, LA departed from the Arctic on 2-Aug. After reaching the coast of the Sea of Okhotsk, it turned south-east to reach the west coast of Kamchatka. The area looks popular for Whimbrels which breed in east Siberia as 3 other Whimbrels, satellite tagged by the Fudan University (Shanghai, China) are aslo around the same area, 2 of those were tagged in Queensland and 1 in Broome.

Fig 5: LA’s first leg of southward migration

Given this is LA’s first ever visit to the breeding ground and its first southward migration, it will be very interesting to see its migration strategy back to Australia. 

As of 6-Aug-18:
Migration tracks of our Whimbrels:

Satellite tagged Grey-tailed Tattler 2018:

Two of our Tattlers have successfully bred in Siberia. They were using different breeding areas more than 1,500km apart, while LDU bred in Krasnoyarsk Krai and LBU bred in Sakha Republic, not too far from Whimbrel KU’s breeding location.

Fig 6: LBU’s and LDU’s breeding location in Siberia

LDU arrived on the breeding ground on 9-Jun. Two locations 20-30km south-east of its nest were explored in the first 2 weeks.  Two weeks later since 23-Jun it had finally settled down at its nesting location. Since then it has hardly moved more than 2km away from its nest.

Fig 7: LDU searching for nesting site

Satellite signal from 2-Aug show that LDU has departed from its nesting location. More accurate signals are to be received in the coming few days to confirm it has started southward migration.

The other Tattler LBU is relatively more efficient in finding a nesting location. Only a week after its arrival, it had determined to nest in a river valley in the north of the Verkhoyansk Range and utilised two other locations, 12km west and 10km south, possibly as foraging sites away from its nest.  

Fig 8: LBU’s nesting and foraging locations

After 6 weeks breeding time, LBU departed its breeding location on 30-Jul and flew 1,400km south to reach a stop-over area in Sakha just north of the Stanovoy Range.

Fig 9: LBU’s first leg of southward migration

Unfortunately, our 2 other Tattler’s transmission have ceased in early and mid-Jun after they reached Russia. It could not be determined whether this is due to breakdown of the tag or the death of the bird.  

As of 6-Aug-18:
Migration tracks of our Grey-tailed Tattlers:

Katherine LEUNG
6 Aug 2018

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