Just got news back on the colour-ringed Sanderling observed at Donna Nook on 4/6/.

'Thank you very much for your report of colour-ringed sanderlings that you observed and photographed. I have good news, the bird on the picture can possibly be only one bird, because the other ring on the right tarsus can only be another yellow, because the other combinations have never been used. The ring on the tibia, which you understandably report as white is actually faded blue (!). All those old blue rings have faded into blue and get reported as white or grey.
It means hat this bird has been ringed in Mauritania and is really old for a sanderling! Amazing also that we only observed it in 2006, while we have returned to Mauritania each winter since 2002!
You can find the details of this bird attached. For two reasons I do not think that the bird on 7 May was the same as the photographed bird on 4 June (1) this combination of rings, with yellow over white on the right tarsus, has never been used and (2) these birds that winter in Mauritania usually migrate northwards only after 20 May until 10 June and never stay longer than a few days in one area.
best wishes,
Jeroen

Colourcode: YWYY Name Ringer: Klaus Günther 2nd Ringer: Bernard Spaans
Ringnumber: H286610 Date Catch: 10/12/2002 Catching Place: Iwik village, Banc d' Arguin
Mauritania 19.52.40 N 16.18.11 W
Sightings of this bird:
Date(d/m/y) Place Observer 2nd Observer 3rd Observer
07/12/2006 Iwik village, Banc d' Arguin Jan van Dijk
Mauritania 19.52.40 N 16.18.11 W
08/12/2006 Iwik village, Banc d' Arguin Bob Loos
Mauritania 19.52.40 N 16.18.11 W
09/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens Edward Koomson
Mauritania 19.52.40 N 16.18.11 W
10/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens
Mauritania 19.52.40 N 16.18.11 W
10/12/2006 Iwik village, Banc d' Arguin Bob Loos
Mauritania 19.52.40 N 16.18.11 W
12/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens
Mauritania 19.52.40 N 16.18.11 W
15/12/2006 Iwik village, Banc d' Arguin Bob Loos
Mauritania 19.52.40 N 16.18.11 W
20/12/2006 Iwik village, Banc d' Arguin Jan van Dijk
Mauritania 19.52.40 N 16.18.11 W
21/12/2006 Iwik village, Banc d' Arguin Bob Loos
Mauritania 19.52.40 N 16.18.11 W
25/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens
Mauritania 19.52.40 N 16.18.11 W
25/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens
Mauritania 19.52.40 N 16.18.11 W
27/12/2006 Iwik village, Banc d' Arguin Jeroen Reneerkens
Mauritania 19.52.40 N 16.18.11 W
04/06/2012 Donna Nook, Lincolnshire James Siddle
United Kingdom 53.28.36 N 00.09.08 E