Over-Summering Ruddy Shelducks at Abberton Reservoir

30th July 2026

Ruddy Shelducks do occasionally appear at Abberton Reservoir, but have you noticed they tend to appear at the same time of year?

Many of us will be aware of the Oare Marshes Bonaparte's Gull which first appeared at Oare Marshes in early July 2013 in its full summer plumage. It then stayed until it had moulted into its winter plumage a few months later and then disappeared, never to be seen again, that is until the next year when it repeated the process. This is the 14th year it has returned and nobody knows where it goes for the rest of the year, but probably not back to the states. It returned on the 3rd July this year.

Well, looking back at my photos and a couple kindly provided by Ian Plume, a similar pattern with the Ruddy Shelducks at Abberton Reservoir has emerged. Here are the seven photos I located, and in some years there were more than one bird present.

August 2011

August 2013

July 2019

July 2021

July 2023: Photo Ian Plume

July 2024: Photo Ian Plume

July 2026

There are two things to notice. The first is that all the photos are taken in July or August, and just like the Bonaparte's Gull this coincides with their adult moult, which in the case of Ruddy Shelducks occurs from mid-July to September. Also all the photos are of females, and here I am assuming that the first photo is of a female with a muddy face.

In my blog of the 8th July 2021 I wrote "Also the female Ruddy Shelduck was back. It is suspected she is from the Dutch population and has been coming here for the last couple of years to moult."

And from my blog of the 14th July 2019 "The origin of these birds is always a discussion point for they have been seen at Abberton several times over the years, but not in the neighbouring areas. They could of course be unringed escapes, but there is a 600-strong feral population in The Netherlands so they could be commuting from there which would explain why they are not being seen anywhere else".

So with a little research I now know this phenonemon goes back to at least 2011 and is still evident day. But although it would appear that the most likely explanation is that they are coming from The Netherlands for their annual moult, it doesn't explain why they are all females!!!

Answers on a post card.

And a special thanks to Ian Plume for the use of two of his photos.