Stunning results from first Turnstone Geolocator

Ken Gosbell, Victorian Wader Study Group, 24th Jan 2010:

Some stunning results have been  received from the first of the 3 Geolocators retrieved from Ruddy Turnstones at Flinders 2 weeks ago.  James at BAS has downloaded successfully and has provided some preliminary results. The Google Earth image shows the bird travelling a trans-Pacific flight path on southward migrationto Australia. While we have sometimes been puzzled by the fewer observations of Ruddy Turnstone on southward migration, I am not aware of trans-Pacific flight paths being postulated. This of course opens up a whole new range of questions.

I am copying below some of the observations made by James when providing the data – you will find them fascinating. I have checked some of these key dates and also examined the records of light values in the arctic where the sudden presence of dark/light indicates the commencement of nesting! I might also add that this bird (9Y) was the one sighted by ChungYu in Taiwan on 11 May.

Bird 7652 (9Y): Rough analysis 22/1/10

A quick summary of movement (timing can be seen in both light and wet/dry data):

• 28/4/09 – departs Flinders, flies north-west
• 3/5/09 – arrives Taiwan
• 20/5/09 – departs Taiwan
• 21/5/09 – arrives Yellow Sea
• 30/5/09 – departs Yellow Sea
• From here the bird travels north-east and gets to about 62N 135E before 24-hour daylight makes location impossible.  However, these fixes are far inland and so must have quite large uncertainty. This 24-daylight is a great shame as it does not give us a very good idea of breeding grounds. However, light data does possibly indicate nesting starting 26/6/09 and ending 16/7/09. At least, this is a period when the light sensor gets a lot of largely irregular dark periods. Usable light data resumes on 26/7/09 but puts the data a little south of the Alaskan peninsula. I am not sure why we have this southerly shift but it could be due to artificially shortened daylight hours (e.g. dirt on the sensor?)…
• 26/7/09 – appears on Alaskan peninsula at about 176W
• 12/8/09 – moves to about 169W
• Although equinox gives indeterminate latitudes, it appears to stay here until we can be sure it is still here on about 10/10/09.
• 14/10/09 – departs Alaskan peninsula, flies south
• 19/10/09 – arrives south end of Gilbert Islands
• 29/11/09 – departs Gilbert Islands
• 3/12/09 – arrive east coast of Australia
• 7/12/09 – arrives back at Flinders neatly

All in all, it is pretty excellent data, just a shame we can’t pinpoint the nesting grounds.