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Ruddy Shelduck with neck band H4 (photo: Guido Keijl). |
Until 2013 many have wondered what the origin is of the ever increasing numbers of moulting Ruddy Shelducks on the Eemmeer in the Netherlands. In recent years, almost 800 individuals were counted here. The origin of these birds is unknown. It was always assumed that these were escapees probably from waterfowl collections and their offspring. However, these moulting numbers are much larger than the Dutch breeding population. In Germany the number of breeding pairs have been increasing, but seemed to be insufficient as well to account for these numbers.
It could not be excluded that we are dealing in Eemmeer with wild birds, originating from southeastern Europe or even further. The European breeding population is located mainly in the region around the Black Sea, in southeastern Russia and Transcaucasia. If the birds (partly) originate from wild populations, this would have consequences for the conservation status of this species. In existing Natura 2000 sites conservation objectives might be set. Ruddy Shelducks are listed on the European Red List as "Vulnerable" and have a relatively small population size. By using color rings (neck bands) and transmitters the origin of the birds can be investigated. The Ruddy Shelduck Working Group has been established with this very purpose in mind. This group consists of Ton Eggenhuizen, Erik Kleyheeg, Kees Koffijberg, Frank Majoor and Jeroen Nagtegaal, and in the first year also Ruud van Beusekom and Dick Jonkers. In July 2013, 827 individual Ruddy Shelduck were counted at the Eemmeer. Of these, 48 birds were caught and fitted with a neck band. A small number also received a transmitter, a GPS logger that transmits data over the GSM network. Also in Limburg the nestlings of a local breeding pair were ringed. In 2014, 64 more were caught, as well as 2 on the island Kreupel and 2 more young birds in Limburg. In 2014 we used a somewhat higher neck band. The group provides information on twitter: @ WgCasarcaNL, through the forum of www.waarneming.nl (in Dutch) and has some progress reports and a symposium-poster available. Some papers are in preparation. Contact with the working group via email. |
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yellow neckband with black inscription (H4) Netherlands 2013 |
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Ruddy Shelduck with neckband inscripted with code N5 (photo: Werner Wolf).