‘Greenland’ Dunlin

A 3rd for Northants?

As part our exceptional wader movement this spring, there have been two reports of Greenland Dunlins – that’s the scarcer race, arctica, which turns up in much smaller numbers than the much more commonly occurring schinzii and alpina. One was with the mixed small wader flock at Stanford Reservoir on 17th May and the other, nicely illustrated in the photos by Bob Bullock here, was at Hollowell Reservoir six days later, on 23rd.

Features associated with this race, breeding in north-east Greenland and Svalbard, were described in Northamptonshire’s first, which was at Summer Leys on 9th May 2013. The excellent images by Bob illustrate the most of the key identification features but they are far from straightforward – particularly on a lone individual, which cannot easily be compared with other Dunlins.

In summary, arctica is slightly smaller than the other two races. It has a shorter bill and it appears generally greyer and less rusty/chestnut on head, mantle, scapulars and coverts. The black belly patch is smaller and usually less solid and the breast streaking is noticeably finer compared with that on schinzii and alpina.

Sounds easy but it isn’t. There is variation. There is also the added complication of first-summer Dunlin of one of the other races, which frequently has reduced black belly patch and may also appear greyer through not attaining full adult plumage. There is also first-summer arctica to consider … so a full suite of characters is the best way to nail one.

In spite of the fact that there was no size comparison made, the Hollowell bird ticks all the boxes, apart from one – and that’s the bill length, which looks longer in some images than in others. This may be as a result of sex, with females being marginally larger and having longer bills. Associating with other Dunlins, the Stanford bird on 17th was, according to the observer, Gary Pullan, short-billed, small and almost stint-like (as well as showing all the other correct features). Apart from tertials and coverts, which are very worn, the rest of the plumage is fresh and ‘classically’ arctica, with the mantle fringes cinnamon-yellow and not rusty-chestnut.

Richard Chandler has commented, “Yes, looks quite good for arctica, with the right cinnamon tones to the upper parts, and a smallish breast patch.  The relatively late date for Dunlin on migration is also supportive. Complications are the rather massive bill – but may be a female – and the worn plumage, especially tertials and wing coverts, which suggest a first-year bird and might be the reason for the rather pale plumage.  But I can’t see any obvious retained juv feathers as they are too worn to show the classic juv dark feather tips.  And would have been good to have had another bird for size comparison. But if I have to put a race to it arctica seems the most likely …”

Gary Pullan also stated, It does look quite good, it seems to be a 1st summer and probably a female given the length of the bill, so that doesn’t help to be absolutely sure in my humble and rather poorly-informed opinion. Saying that the new scaps etc are not particularly bright and the belly patch rather restricted (age related though?), both good points. Shame it was on its own, and I didn’t see it! The Stanford bird had a remarkably short bill, rather stint-like, I estimated it comparable in length to the distance from the bill base to just about the ear coverts, whereas this bird seems to have a bill the same length as the head itself. It was markedly small too and was probably a male.”

Many thanks to Richard Chandler and Gary Pullan for their comments.

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Glossy Ibis at Summer Leys

The First in Spring

The words ‘Glossy Ibis’ and ‘Northamptonshire’, when occurring together in the same sentence, are now predictably accompanied by adjectives such as ‘short-staying’, ‘fleeting’, or ‘transient’ to describe this species’ visits to the county. The first one to occur in spring followed the now well established occurrence pattern seemingly mandatory for Glossy Ibises in Northants. This individual managed little more than two hours at Summer Leys today, having been discovered at 11.30, before flying off west at 13.35. Images below from Alan Coles.                                                                                                                                                                                       This is only the fifth county record, following singles at Ravensthorpe Reservoir on 20th September 2002, Pitsford Reservoir on 17th September 2010, Stanwick GP on 12th October 2013 and Daventry CP on 28th September 2016.

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‘Tundra’ Ringed Plovers

Late spring sees small flocks of Ringed Plovers inland, moving north. Most, if not all will be ‘Tundra’ types, probably of the Scandinavian/Russian/Siberian race tundrae, but possibly also psammodroma, which breeds no further away than Iceland, with its range extending to Greenland and north-east Canada. Both races are very similar, being slightly smaller, darker and marginally smaller-billed than our ‘own’ nominate race hiaticula (more here).

There have been a handful of reports this week, including 5 at Earls Barton Gravel Pits on 6th and one there on 7th, plus 6 at Stanwick Gravel Pits and 7 at Pitsford Reservoir yesterday.

Presumed ‘Tundra’ Ringed Plover, Earls Barton GP, 7th May 2017 (Douglas McFarlane)

Presumed ‘Tundra’ Ringed Plover (right) alongside summering (presumed) nominate Ringed Plover, Earls Barton GP, 7th May 2017 (Douglas McFarlane)

This one at Earls Barton GP appears to be a female as the ear coverts are not solidly black and the band around the neck is thin and brownish at the rear but it was noticeably smaller and darker than the accompanying bird, which is presumed to be a breeding hiaticula.

Comments welcome.

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Summer Leys’ Rufous morph Cuckoo

The images from Alan Coles, below, capture a rufous morph Cuckoo in flight over Summer Leys LNR on 5th May. This is interesting on two counts – firstly, because this colour morph is generally uncommon, with only one or two reported in Northants per year and secondly, because records in recent years have come from Summer Leys/Earls Barton Gravel Pits (last year’s here) suggesting this may be the same returning individual.

Rufous morph Cuckoo, Summer Leys LNR, 5th May 2017 (Alan Coles)

Rufous morph Cuckoo, Summer Leys LNR, 5th May 2017 (Alan Coles)

Rufous morph Cuckoo, Summer Leys LNR, 5th May 2017 (Alan Coles)

Colour polymorphism in birds is determined genetically and the similarities between plumages of rufous females and Cuckoo fledglings (see here) suggest that the rufous morph is simply a colour alternative to the grey morph and might have arisen through paedomorphic retention of juvenile plumage to adulthood (see Trnka, Trnka & Grim).

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Black-throated Diver at Pitsford Reservoir

A 20th for Northamptonshire

A stunning summer-plumaged Black-throated Diver was found by John Friendship-Taylor at Pitsford Reservoir during the closing hours of daylight yesterday evening (6th May). Visible from the feeding station area at the mouth of Scaldwell Bay, it was still present at dusk and remained there until 05.20 this morning, when it was seen by Antony Taylor to fly off north.

Black-throated Diver, Pitsford Res, 6th May 2017 (Bob Bullock)

This is only the 20th record for the county, following the last in 2012, when one was at Stanford Reservoir. Fifty-five percent of all records have come from Pitsford.

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Stepping up to the mark?

An interesting Buteo at Fineshade

The amazing variability in the plumage of Common Buzzards of two widespread races – ‘our’ local buteo and eastern vulpinus (Steppe Buzzard) – is well known, with some examples of both being almost impossible to tell apart.

Confronted with one such individual at Fineshade on 2nd May, Jeff Blincow was quick to capture some images of what, he says, he wouldn’t have given a second thought to identifying as a Steppe Buzzard had he been in Africa or the eastern Mediterranean region. Having seen Jeff’s excellent photos, reproduced here, I would have reached the same conclusion. “It was obvious with the naked eye,” Jeff said, and it immediately stands out with a conspicuous light rufous tail and foxy underwing coverts.

Buzzard, Fineshade Wood, 2nd May 2017 (Jeff Blincow)

With an apparently dark eye and barred, rather than streaked, underparts, it would appear to be an adult or near-adult. But is it a Steppe Buzzard? The rufous element to the plumage, apparently less obvious in the images than in the field, are the only pro-Steppe features, although many darker Steppes can look remarkably similar to Commons and, just to complicate matters, there is an intergrade zone in eastern Europe where the two races meet.

Buzzard, Fineshade Wood, 2nd May 2017 (Jeff Blincow)

There are more pro-Common features with this bird, however, with the barring on the secondaries being quite broad and extending well on to the primaries which, themselves are not solidly dark-tipped (some broad barring still present immediately beyond the dark). There is also a less intense underparts pattern than exhibited by typical Common Buzzards, i.e. dark head, neck and chest separated from variable dark flanks by a whitish or vary pale breast band.

Buzzard, Fineshade Wood, 2nd May 2017 (Jeff Blincow)

Compare the Fineshade bird with a typical Steppe Buzzard, which has narrower, finer and more restricted barring against a whiter background on the underwing. The individuals in the images below, taken by Mark Pearson in Israel in March, shows more evenly patterned underparts, although the ‘ghost’ of the underparts pattern described above is still apparent.

Steppe Buzzard, Israel, March 2017 (Mark Pearson)

Steppe Buzzard, Israel, March 2017 (Mark Pearson)

And a first-year individual, pale, streaked not barred and with a pale iris …

Steppe Buzzard, Israel, March 2017 (Mike Alibone)

The Fineshade bird is interesting. It is likely to be ‘just’ a Common Buzzard but may also be an example of an eastern European intergrade – and we have had a relatively prolonged period of easterly winds recently …

Comments welcomed and many thanks to Jeff and Mark for their images!

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Wing moult on migrant Northern Wheatear

A distant Northern Wheatear in a field off Mary’s Lane, opposite the rear entrance track to the Paul Britten Hide at Summer Leys, attracted my attention yesterday. It turned out to be a rather smart male, showing features characteristic of the Greenland race leucorhoa (large, upright, long-legged and swarthy with rich orange throat/breast, extensively orange-washed underparts and noticeable brownish cast to upperparts). While I was trying to digiscope it through the heat-haze, another wheatear appeared nearby – this time a female. On switching attention to it, I noticed it was asymmetrically marked. The uppermost and lowest tertials of its left wing had broad whitish-buff fringes, indicating unmoulted winter/1st winter feathers, while the middle one was the ‘normal’ plain colour of a 1st summer/adult. Its right wing appeared to show a single, plain adult middle tertial with the lowest and highest ones seemingly absent. I have not noticed this on Northern Wheatear before and the effect was quite striking. I had always assumed that wing moult took place before migration, although this would indicate that this is not always so. I know that some species’ moults can be arrested during migration and, according to BWP, Northern Wheatear may or may not moult 1 or two tertials pre-breeding, but I would not have expected such asymmetry as was apparent with this individual.

Any comments welcomed.

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