Leucistic juvenile Starling

Phil Jackman forwarded these images of a leucistic juvenile Starling present in his Kettering garden this weekend. While generally uncommon, leucism (really a lower concentration of melanin) in juvenile Starlings has been recorded on numerous occasions and invites confusion with juvenile Rose-coloured Starling which, however, has a largely yellow bill (especially at the base) and pale lores.

Leucistic juvenile Starling, Kettering, 5th July 2014 (Phil Jackman)
Leucistic juvenile Starling, Kettering, 5th July 2014 (Phil Jackman)

Also, this individual has already begun its post-juvenile moult, which commences with the wing feathers – in this case all the juvenile greater coverts, except the outer two, have been replaced.

Leucistic juvenile Starling, Kettering, 5th July 2014 (Phil Jackman)
Leucistic juvenile Starling, Kettering, 5th July 2014 (Phil Jackman)

This feather tract is again different to the equivalent plainer feathers of Rose-coloured. It’s interesting that these first-winter feathers are apparently normal, suggesting the bird’s leucism (lack of melanin) is age-related.

Many thanks to Phil for the images of this interesting bird.

The Week in Focus: 28th June to 4th July 2014

Warm and dry with variable light winds gave way to south-westerlies and rain at the very end of the period. A largely quiet week, it was marked only by the appearance of more southerly-heading passage waders.

Last week’s two Ruddy Shelducks at Pitsford Res had commenced body moult and the male, at least, had become flightless as a result. Clearly they will be there for the foreseeable future.

Ruddy Shelducks, Pitsford Res, 3rd July 2014 (Clive Bowley)
Ruddy Shelducks, Pitsford Res, 3rd July 2014 (Clive Bowley)
Ruddy Shelducks, Pitsford Res, 4th July 2014 (Alan Coles)
Ruddy Shelducks, Pitsford Res, 4th July 2014 (Alan Coles)

An early (or more likely mobile, summering) Wigeon was at Stanwick GP on 1st, along with last week’s female Garganey all week and the same site hosted up to eight Little Ringed Plovers while up to six, including young, were present at Summer Leys LNR. Black-tailed Godwits made their autumn debut this week with one at Pitsford Res, and seven dropping in briefly at Summer Leys, on 29th, followed by three at the latter site the following day and five at Stanwick GP on 1st. Those at Summer Leys were of the race islandica and it is more than likely the others were also Icelandic in origin. A maximum of seven Green Sandpipers was also recorded at Stanwick GP on three dates and one remained at Summer Leys from 28th to 30th, while both localities notched up a single Common Sandpiper. The number of Yellow-legged Gulls at Stanwick GP climbed to nine – up four onlast week’s total, a male Black Redstart was near Rocking ham Speedway (Corby) on 1st, the singing male Grasshopper Warbler remained at Fermyn Wood CP on 29th – the same site hosting two Crossbills on 3rd, while another Crossbill was at Denton Wood on 30th.

Ruddy Shelducks: Northamptonshire and the European Perspective

It has been less than a year since I summarised the Northamptonshire status of Ruddy Shelduck and speculated on the possible origins of birds visiting the county. There is an annual pattern of late summer/early autumn occurrences which ties in nicely with the now well established post-breeding, summer moult migration to The Netherlands. It would appear that birds occur locally as a result of dispersal from The Netherlands after they have completed their full body moult, which leaves them flightless for about four weeks.

There are currently two – a male and female – at the southern end of Pitsford Reservoir, which were first discovered on 24th June – a somewhat earlier arrival date than would normally have been expected.

Ruddy Shelducks, Pitsford Res, 30th June 2014 (Mike Alibone)

The date coincides with the arrival of others in the UK: two in Gloucestershire on 19th and singles in Staffordshire on 25th and Cheshire on 28th, while the build-up in The Netherlands has also begun with two hundred or so at Vreugderijkerwaard, west of Zwolle (remember the Hawk Owl? 🙂 ) on 27 June. A flock of ten had also reached the west coast island of Texel by 25th June where, according to René Pop, they are very unusual; from here it is just a short hop to East Anglia …

The Pitsford birds are in active moult and the drake at least is flightless, having shed all its primaries and secondaries. This, then, begs the question, are we now getting some of the ‘Dutch’ birds before they moult?

Flightless drake Ruddy Shelduck, Pitsford Res, 30th June 2014 (Mike Alibone)
Flightless drake Ruddy Shelduck, Pitsford Res, 30th June 2014 (Mike Alibone)
Flightless drake Ruddy Shelduck, Pitsford Res, 30th June 2014 (Mike Alibone). Note total absence of primaries and secondaries.
Flightless drake Ruddy Shelduck, Pitsford Res, 30th June 2014 (Mike Alibone). Note total absence of primaries and secondaries.

The origin of the ‘Dutch’ birds is still not fully resolved but we are now more than half-way to understanding where they come from. In an attempt to discover the source of the summer moulting population a Ruddy Shelduck Work Study Group was set up and, in 2013, it launched an investigation into the origin of the large numbers (eight hundred or so) summering at the Eemmeer as well as those elsewhere in The Netherlands. Forty-eight were trapped and fitted with individually numbered yellow neck-collars and seven were fitted with GPS transmitters.

As a result of this we now know that many – if not all – of these birds are from feral populations in Germany  and Switzerland, and it has been established that birds from the German lower Rhine and the Swiss birds are connected to each other. However, there are still a number of individuals with collars which have not been seen after having left the Eemmeer in August 2013. The Dutch are still hoping that these may be from the ‘wild’ population in south-east Europe. It’s nice to dream …

Back to the feral birds. The German and Swiss populations are said to be growing, particularly around Lake Constance, at the tri-point of Switzerland, Germany and Austria, where approximately six hundred and forty were counted in February 2014. There is some concern in the region that they may successfully compete with other hole-nesting species and this has conservation implications. For this reason, along with the fact that this is a European ‘C’ list species and, therefore, potentially worthy of admission to the British list, shouldn’t we be taking Ruddy Shelducks a Tad more seriously?