It is part of a Dutch project, and the co-ordinator (Wim Tijsen) sent more details to Charlie, as follows...
The reported sighting on 16 December is good news (Wim's words) because it
is the first proof that this bird is over-wintering on the Exe Estuary where it
has bee seen twice before during this Autumn and previously on the Exe at Turf
on 10 November 2005. The bird was first rung as an immature bird in 2004. It is
a female and a proven breeder both last year and this, very close to where it
was rung at Westerland, Netherlands. The green flag is a transponder
and was placed on the bird 13 May 2011. A metal circle is placed around the nest
area and each time the bird enters or leaves the circle this is recorded via the
transponder.
Here is a copy of an email
received from Wim that explained more about the bird.
" ........They raised at least one or more juveniles this spring despite the very dry summer. But the farmer I am working with is into nature farming and mow's his land very late, after 8 june or later for the birds in schedules. The farmer (Jan Mulder) also caught her back by hand when she was a juvenile. My main study area is around a skating rink in a open polder of 40 hectares, the skating rink is specially a wet-grass-land area, where the farmer get paid for. It is wet for 60% untill 15-5.This year my farmer pumped his land wet during the dryness, specially for the meadow birds."
A few more details on Charlie's blog here.
" ........They raised at least one or more juveniles this spring despite the very dry summer. But the farmer I am working with is into nature farming and mow's his land very late, after 8 june or later for the birds in schedules. The farmer (Jan Mulder) also caught her back by hand when she was a juvenile. My main study area is around a skating rink in a open polder of 40 hectares, the skating rink is specially a wet-grass-land area, where the farmer get paid for. It is wet for 60% untill 15-5.This year my farmer pumped his land wet during the dryness, specially for the meadow birds."
A few more details on Charlie's blog here.