Ruddy Shelducks. By Steve Connor

During last year’s Birdfair at Rutland Water in mid-August, to which WVBS had organised a coach
outing, there was a fair bit of interest paid to a Ruddy Shelduck which was present there, with a lot of
photos of it posted online. It had attracted attention as it had arrived during a period of a minor influx
of Ruddy Shelducks into the UK, mainly at East Coast locations, with a total of about 50 birds seen,
including a flock of 8 in Northumberland. Again this year, there have been small numbers seen in the
UK, including a group of 9 in Somerset in the last week of July, which moved to Oxfordshire in the first
week of August.
A very low number of pairs of Ruddy Shelduck breed ferally in UK, and these recent annual late
summer influxes no doubt originate from overshoots from the large flocks which gather in the
Netherlands at this time of year.
In the Netherlands, where the Ruddy Shelduck is known as the ‘Casarca’, late summer flocks are in
high numbers, and centre on the huge inland seas east of Amsterdam. In August in recent years,
there have been three-figure flocks at 6 sites thereabouts. There is undoubtedly a lot of interchange,
but the prime site, Eemmeer, had peak counts in 2018 of 880 on August 1st, with 1070 counted there
two days earlier on July 30th, and in just the last few weeks of this year, 2020, the same site has had
peak counts of 900 on July 31st and 650 on August 6th. Nearby Ijsselmeer had similar sized
gatherings, of 800 on July 24th and 600 on August 7th 2020.
A ringing and tagging programme was carried out there from 2013 to 2016 to attempt to establish
the origins of these increasingly large late summer gatherings, and they have found that they appear
to originate from a large breeding population on the German/Swiss border.
Wild Ruddy Shelducks breed in far South-Eastern Europe and around the Caspian and Black Seas,
so these German/Swiss birds are not wild, but are clearly a very well-established population with a
feral background.
Accordingly, the Dutch birders include them on a Category C type basis (self-sustaining feral
population), and there have been calls for the BOU to follow suit and add the species to the British
List. But whilst they are self-sustaining in Central Europe, they are not so here, making it difficult to
categorise such birds in the UK, and the species currently languishes in Category B. Consequently,
in the meantime, County Bird Recorders have no need to decide whether or not any Ruddy Shelduck
is wild or from the Central Europe population, as they all go straight into the Escapes category.
So now is about the right time to be alert to the possibility of an arrival of Ruddy Shelducks,
particularly in groups. However, just because a Ruddy Shelduck may turn up here during the influx,
that won’t necessarily mean it is from the Dutch gathering, particularly if it is a lone bird, as escaped
individuals are regularly wandering in our area at all times of year. One was in the WVBS area, near
Guist, in spring 2019, on April 1st, and possibly the same bird in the Pensthorpe/Great Ryburgh area
from August 29th, and still lurking there until at least mid-March 2020.

The Guist bird, April 1st 2019. A ‘pure’ bird, showing black legs.

 

Finally, also beware a hybrid. Ruddy Shelducks very much like consorting with Egyptian Geese, and
have bred with them in the UK and produced hybrid young. There has been at least one such hybrid
bird wandering Norfolk, including in our area, for two years or more, masquerading as, and looking
very similar to, a Ruddy Shelduck – until closer views reveal its thick, pink, Egyptian Goose legs!

The hybrid showing its legs

 

The hybrid – Guist, July 18th 2018

(Photo credit to Steve Connor)

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