On the 12th February 2000 we caught and ringed the first Shelduck for the Lower Derwent Valley on the top pond at North Duffield Carrs, and now, 25 years later, we've just ringed the 1000th individual at Bank Island. Whilst that represents something of a milestone itself, the numbers are not the important thing, but rather the amount of data that those birds (as part of our long running colour-ringing project) have produced over the years, to help our understanding of Shelduck both on the reserve and in the wider area.
‘Our’ birds include: the longevity record for the species from the BTO ringing scheme (over 20 years old), regularly returning breeding birds to the LDV year after year, and birds visiting moulting sites on the Dutch/German Wadden Sea, the Humber and other estuaries around the UK.
The map below shows a strong association with the northwest, and it is suspected that the Dee Estuary could now be a new moulting site, with young birds beginning to recruit into it over the last decade or so. Indeed, stable isotope work carried out by Ros Green (as part of a PhD study into the species) has provided very different data from the Dee compared to all of the other northwest European moult sites, and it will be interesting to see how that moulting site develops and with it, the links to the Lower Derwent Valley. A total of 100 birds had small feather samples taken by our team over the 2024/25 winter to allow such analysis, and help us understand how Shelduck use the site here. Many thanks to all involved for helping to collect this valuable data.
No comments:
Post a Comment