News of a new transmission we have just received marks the most exciting movement by any of the birds we are currently tracking so far. A signal from Raushan from September 22nd now almost certainly locates her in Northern Pakistan a few kilometres north-east of Thawoos, near the Yasin valley. This location also confirms she is indeed on an Amazing Journey that is providing pioneering data on a previously uncharted easterly migratory route for this species.
The significance of her location is considerable as it marks the first time we’ve witnessed a Sociable Lapwing embarking on a migration along this flyway. While we knew Sociable Lapwings regularly wintered in north-western India we have previously had no evidence of where they’d come from or the route that they’d taken. Greater knowledge about this ‘new’ route will also help us establish whether these birds might face previously unknown threats along the way.
To date, all previously tracked Sociable Lapwings have taken a westerly route out of Kazakhstan before heading south typically through south-western Russia and Georgia down to eastern Turkey and beyond to end up in the Sudan.
Raushan initially gave us reason to believe she was heading west to join up with other birds in Central Kazakhstan before following them further west. Her last location was actually very close to the Central Kazakhstan breeding locations at our study site near Lake Tengiz, so to now discover she has made a sharp turn south rather than continuing west is a big surprise.
As a consequence of this report we have alerted our project partners in India to be prepared to go into the field to try to locate the migrating flock in anticipation Raushan’s wintering area will eventually be in north-western India.
Analysing satellite tracking data is not as straightforward as it might seem. Each time we receive a set of coordinates they are categorised by accuracy. While they can be accurate to within 250 m, locations are usually much less accurate than that. The accuracy of the coordinates is determined by the number of times the satellite passes over the bird and picks up a signal while it is transmitting.
To further complicate matters, each report also contains two locations – one is correct and the other is not. Knowing which is right requires careful interpretation and is usually best done retrospectively – only once further signals have been received. On this occasion the first (and generally the correct) pair of coordinates places her in Northern Pakistan and the alternative set of coordinates locates her some 200 km away in north-eastern Turkmenistan. A further piece of corroborative evidence that supports our belief that she is in northern Pakistan rather than Turkmenistan is that there have been several historical records of birds in this particular location.
At this stage – Tuesday September 28th – we have received no further reports from Raushan and we anxiously await more news to confirm her location and onward route.