Author Archives: nilsvanduivendijk

Caspian Stonechat ssp variegatus on Vlieland


Deception Birding!

by Nils

21 years ago, Hans ter Haar († 2011) invented a new way of rarity hunting in the Netherlands. After years of the classic Dutch Birding (whole) weeks on Texel in October, his eyes got stuck on Vlieland. Vlieland, next to Texel, was much narrower, almost wholly accessible and much smaller than Texel. So, it looks much better to cover with a fairly small group of birders. Also he thought that one full week was not the way; too much chance for a long slow period and too much chance of ‘the same birds’ every year. No, the plan was three long weekends spread out over the autumn between early Sept and late Oct. With not too much expectations but with humour and some self-mockery, Hans and his friends called their experiment ‘Deception Tours’.

Indeed some weekends were a deception (motivations were always high, but birds sometimes few), as on all island which lean on migration, but the concept was brilliant! The list of rarities found during the Deception Tours weekends is much too long to mention here, but to highlight a few: 5 new species/taxa for the Netherlands (Yellow-rumped Warbler, Turkestan Shrike, Pallid Swift, Northern Waterthrush and indeed Caspian Stonechat). The 2nd Bonelli’s Eagle for the Netherlands, and Vlieland, as small as it is, now host about half or more of all Dutch records of Olive-backed Pipit (7 in one weekend of which a group of 4!), Yellow-breasted Buntings, Rustic Buntings and Radde’s Warblers (4 on one day!). Hans sadly died just before the third weekend last year. Until his last days, although already very weak, he still supported us on Vlieland by phone. His motivation, insights, leadership and great company we will continue to miss.

In the overcrowded Netherlands, Vlieland is the most ‘remote’ inhabited island. It has a population of 1100 people and the ferry arrives just three times a day. UK birders will be laughing now, and yes we can only dream about isles like Fair Isle, Foula, St Kilda etc. Cars are not allowed for visitors on Vlieland, so birding goes by bike and by foot.

The mobile network doesn’t cover whole Vlieland so if you come across this without receiving the message earlier, you know there is sometimes very wrong (uhh, good!).
The Northern Waterthrush twitch, Sept 2010
Photo by Henk van Rijswijk

October 2012

The weather maps are my compass. After quite a long period of bad situations, finally a narrow ridge of high pressure waved over Southern Scandinavia during the second Deception Tours weekend (5th -7th Oct). On Saturday early morning the back of a frontal zone passed Vlieland and already huge numbers of thrushes, mostly Redwings were coming in while still raining. The excitement in the air sunk quickly down into our veins, our team prepared for code red…

For me and my friends, the fall phenomena is a wonderful event in itself, whatever including rarities or not. But the excitement went to a climax when Eddy Nieuwstraten and Han Zevenhuizen bumped into a Siberian type Stonechat with white in the tail… A ring from Han and within minutes I was with them: WOOOOW a cracking male variegatus!! Beside the ‘black-eared wheatear-tail-pattern’ the bird shows • a huge whitish (not uniform buffish) uppertail-coverts and rump-area, • very broad orange neck-side patch, strongly narrowing the black mask towards the rear-side • sandy-grey fringes to the mantle-feathers and scapulars, and • an almost maximum contrast between black underwing-coverts and white bases of the underside of the flight-feathers (latter from photo’s). All spot-on for variegatus.

In flight the bird gives a very pied impression…
Photo by finder Han Zevenhuizen

The bird was a splendid male with such a deep black face, seemingly full set of adult-type wing-coverts, narrowly pale edged primary-coverts and blackish primaries that, at first I thought it have to be an adult male. I knew that at least some first winter males variegatus are much more ‘adult-like’ than maurus first winter males, but this seems too much.

In the 2nd part, below, the ageing of this beauty is further clarified. The earlier presumed age as a first winter by the presumed diagnostic tail-feather shape appeared to be incorrect.

Note the nasty swellings at the tarsi and toes, which probably also effected the leg-coloration.
Photo by Eric Menkveld

The taxonomic situation of variegatus is still unclear, but for the time being widely regarded as a form of Siberian Stonechat and forms a group with armenicus: the Caspian Stonechat. Whatever future DNA studies will discover, for birders, the males are very distinctive by at least their tail-pattern. I think the most interesting thing is that first winter males variegatus in autumn are often already much more ‘male-like’ compared to first winter male maurus (which are often hard to tell from females). To highlight some possible reasons for this: • a difference in body moult-strategy between the two taxa (with maurus acquire a black mask by moult not before the winter)? • larger pale tips to the body-feathers of maurus, concealing the male-like plumage tracks? and/or • earlier breeding season of variegatus (due to the more southern breeding range) resulting in older first winter birds which are more advanced and thus more ‘adult-like’? As far as I know, this is not clear, and some first winter male variegatus are much less advanced and thus more similar in body-plumage to maurus. Maybe there are readers who know more? The Vlieland-bird had already moulted most or all wing-coverts, some secondaries and possible the upper two tertials. Also several secondaries went missing during its two week stay, maybe due to active moult. The more adult male-like plumage compared to most vagrant (first winter) maurus in Western Europe in itself seemed to be an interesting starting point for future discoveries, before the tail-pattern is seen. Females are, as far as I know, identical to maurus (females). Maybe some show little pale at the base of the outer-tail feathers, normally invisible in the field.

Part 2: Caspian Stonechat on Vlieland, the ageing reviewed

Thanks to Magnus Hellström, Tom van de Have and Brian Small, now we can firmly say that it is indeed an adult (2cy+).

Very pointed tail-feathers with large white tips; incorrectly thought by me (Nils) to exclude an adult, despite the otherwise very ad-like appearance.
Photo by Arnoud van den Berg

Magnus Hellström: tail of fresh adult autumn (2cy+) male stejnegeri, Beidaihe, China September 2012. Although there are some average differences regarding the shape of the tail-feathers, both age classes (1cy and 2cy+) shows quite broad feathers with a rather protruding and pointed tip. Note also the pattern/coloration: in average, adults generally show a darker black feather with a pale tip/edge that is whiter and more sharply set off. In juvenile males the feathers are usually more brownish black with a tip/edge that is more buffish and often more diffusely set off.
Photo credits: Beidaihe Bird Observatory.


Here, the primary coverts are visible and show to have only a very narrow fringe which is even more narrow along the tip. In first winters the fringe should be thicker, often more frayed and most thick along the tip.
Note also the adult-type wing-coverts with white fringes which not reach the base of the feather. Well advanced first winters could show at least some adult-type coverts.
Photo by Cock Reijnders

Here the uniform and deep black face is well visible; typical of adult males form the ‘redstart/wheatear-group’ in autumn. First winters are more extensive pale tipped including the loral area.
Photo by Marijn van Oss




Pallid Harrier: Next step in status change

First-summer male undertakes post-juvenile moult in the Netherlands.

by Nils

Well within the time of my birding life, Pallid Harrier was nothing less than a mythical species. Nowadays it is much less rare in NW Europe (in the Netherlands we can call it a rare to even scarce migrant now); but still today, many birders will get a magic feel when they see a Pallid Harrier. In Dutch language the species is named ‘Steppe Harrier’, which further add to the magic (and because I know MG likes it: exactly translated Steppe Chickenthief). It makes me still dream away to its formerly normal range of vast steppes in ‘far eastern’ countries. But it also is just a wonderful bird!

The recent high numbers in Europe are unlikely explained alone by the increasing knowledge of the immature and adult female plumage’s, or by the now many, almost daily occupied migrations watching points either. Although naturally these factors have add to the overall picture, the species must be really much more common today (in western Europe) than a decade and more ago; going through a remarkable rapid status change.

In the Netherlands the spring of 2012 shows just the expected pattern with several 10s of records of mainly migrating individuals. The first individuals typically start to appear from the beginning of April (so, much earlier than Montagu’s).  The settling down of a male that starts his first complete moult was again a new phenomena in the row and gives us the nice opportunity to follow the progress of the chancing plumage.

The bird was found on the 6th of May and stayed mostly in agriculture fields in the county Drenthe until at least the end of August.

As usual in 2nd cy spring Pallid Harrier, in the beginning the bird was very juvenile like. Only some dark streaks on the crop-area betray the first signs of post-juv moult, possible acquired in an earlier stage. The pale iris immediately confirm it’s a male.

13 May (photo by Gerard Sterk)

On or just before 20 May the complete moult really started; both p1 were dropped and on 26 May p2 on the right side. From then the primary moult takes a sprint with up to p5 dropped on 5 June. Also many greater upperwing coverts were dropped, but no underwing coverts.

5 June (photo by Claudia Burger)

Until 14 June no extra primaries were dropped but p1-p5 were more than half grown.

21 June: p1-p5 are fully grown (being typically uniform blue-grey unlike any other harrier at this stage); the body and underwing coverts were still unchanged, but the greater upperwing coverts were replaced (greyish; not visible in this picture). (photo by André Strootman).

26 June: new brown-greyish scaps and tertials appear.

11 July: the first secundaries are replaced (looks like s3-4), the head and underparts are moulted (crop-area again?). Now the breast and flank are quite extensively dark streaked, maybe surprisingly for a male! The axillaries and median underwing-cov looks still juv-type. The primary moult way have reached p8 (which is dropped), p9-10 are still juv-type. (photo by Claudia Burger)
6 Aug: juv p10 is still present, p9 is dropped. The underwing coverts and axillaries are almost fully moulted, the dark central secundaries are still juv-type. (photo by Michel Linnemann)

On 22 Aug, the last day that the bird was photographed so far, there seemed no juv secundaries left and the new p10 was growing. So, with the last stage under way this fine bird will likely be gone soon.

Interestingly, this male shows more dark pattering of the underparts than normal in 2nd male after the complete post-juv moult, but it is far from unusual.

Many thanks to Frank Neijts and especially Vincent Hart and of the administrator-team of for their great help in sorting out all the pictures and making contact with the photographers, who are also greatly thanked!

Britain’s next?!

Pygmy Owl: heading in the direction of the UK.

by Nils

Less than 10 years ago, Pygmy Owl was a dream-on-babe-bird in the Netherlands. Although the species was known to breed increasingly closer and numerous to the border in Germany, many Dutch birders where still surprised when the first one for their country was reported. That probable window victim was picked up, presumed to be a Little Owl and photographed. It recovered in minutes and flew away; months later it was re-indentified as Pygmy Owl on the pics… intriguingly it was in the north of the country.

Nearly juvenile Pygmy Owl, Friesland, Netherlands, 2nd August 2012. photo by Ruurd Jelle van der Leij.

After that first record things goes fast with Pygmy Owls in the Netherlands and last Thursday the 2nd of August, the 7th Dutch record was a fact. And a bizarre record it was! Ruurd Jelle van der Leij and Mark de Vries were busy on a bird-photography-day along the north coast of Friesland. At the end of the day they returned to the pier of Holwerd to try on Little Terns again. While driving over the road, which is actually situated IN the Waddensee, they passed a tiny piece of ‘something’ at the roadside. It could be anything; a piece of paper, a cola tin, even a bird. So they stopped, looked back with their bins and saw… a Pygmy Owl! This dead end road in the Waddensee is surrounded by salt-marsh land, a land-winning project (land-winning from the sea is so typical Dutch; give them the job, and they drain the North Sea between the UK and the Netherlands…). Trees are far away and very few on the neighbouring mainland too. The bird looked weakened and could be approached very closely until it flew off surprisingly healthy, to the dead end of the road. Thorough searches did not result in the re-finding of the bird.

I think it is fair to say that our Pygmy Owls are most likely come from the expanding German population, and not (directly) from Scandinavia. According to BWP and the EBCC Atlas of European Breeding Birds, first year birds are prone to dispersing. Nevertheless a youngster in August on a place still far from the known breeding range and away from any trees along the edge of the sea is still a great surprise! It also gives rise to the speculation if the species is actually already breeding much closer, even IN the Netherlands?? If not yet, it would not surprise me if it will do in the near future.

Nearly juvenile Pygmy Owl, Friesland, Netherlands, 2nd August 2012. photo by Ruurd Jelle van der Leij.

This little fellow looks indeed right for a youngster with its pure brown and fluffy nature of most of the plumage, lack of clear barring on the flank and only very few pale spots on the crown. Note that it has started to moult the inner coverts which are clearly more grey.

Six out of seven of our records are now in the (far) north and last Oct one was even found in the northern tip of Texel. Quite hilarious the Texel-bird was accidently photographed by someone at one of the islands hotspots for vagrants, during a busy day with birders. Later that day the photographer met some of the birders and asked him, showing the back of his camera: ‘I guess this is a Little Owl I photographed this morning…?’ The bird was never seen again. Several birders had passed the place where the owl was photographed that morning. One of my best birding-friends told me that he had stopped by a bush were he dreamt: ‘how should a Pygmy Owl look like here…’. We now know, that was THE bush, so perhaps the bird was looking at him at that moment!

That Texel-bird had only to jump over the North Sea to reach Norfolk…, but is it capable of that? Anyway, if the expanding of the population from east to west continued, more individuals will arrive and stop or not(!) on our north(west)-coast. Our lesson: watch out for claims of extremely fearless ‘Little Owls’ on strange places, or quotes on the internet like: ‘funny confiding tiny owl photographed’….

Strange black-and-white wheatear in the Netherlands

On famous Dutch rarity island-Texel,

Monday 21st of May 2012

by Nils

Frits and Trudy Stoekenbroek find and photographed an odd but very interesting looking male wheatear.

Back at home, five days after their find, Frits and Trudy tentatively identified their bird as a Finsch’s Wheatear and upload the photographs on a popular Dutch site for field-sightings. On that Saturday I was on Texel when the pager said: Pied Wheatear, Texel, there and gone, five days ago…, including a link to pics of the bird. I quickly looked at the available pictures on my mobile phone… “Wow, what is this!, I shouted (OK in Dutch and to be honest not exactly the same words in translation…). Some pics indeed showed a male Pied-like looking bird with a strange shaped mask but the fight-shot clearly showed a narrow white ‘back’; so Pied, no way! It does not felt right for any of the two black-eared’s either, but what else? At that moment resident Texel-birder Arend Wassink (‘Mr Kazakhstan’) (see his wonderful website on Kazakh birds phoned me to discuss the bird. He immediately came up with the option that the bird looks good for a hybrid Eastern Black-eared x Pied Wheatear, an option that indeed seem to explain the strange mix of features, but it had to sink down by me for a while…

To put you in our place on that moment, here the most relevant pics, what do you think (before reading further?)

You will probably have noticed the strange combination of ‘key-features’ of this bird which are summarized below, and maybe you have found even more.

•Long extension of black from the throat-patch towards -and seemingly connecting with- the mantle/shoulder.

•Almost completely black-and-white plumage (some peachy wash is just visible on the centre of the lower breast).

•Very little black above the eye and above the bill.

•Narrow white central upperparts sandwiched between completely black scapulars.

•Sharp-dressed, adult looking. However the clear moult contrast in the greater coverts (long uniform black inners against short, pale tipped and browner outers) in addition to the brownish primary coverts is indicative of a first summer plumage.

•Not extremely long primary projection.

•Tail-pattern typical of Pied, Cyprus, Eastern and Western Black-eared Wheatear.

This combination of characters does not seem to match a certain species, and indeed most are a mix of (Eastern) Black-eared and Pied features or something in-between… Of course hybrids do not necessarily show a perfect mix of both parents characters.

Hybridization seem to occur quite commonly in certain areas and there seem to be even a stable hybrid population! See the reference below taken form Wheatears of Palearctic – Ecology, Behaviour and Evolution of the Genus Oenanthe. Panov, E N 2005. Sofia-Moscow kindly send by Arend Wassink.

‘Hybridogenous populations have been studied in northern Iran, eastern and north-western Azerbaijan, in Dagestan, and at Mangghyslak peninsula and westernmost edge of the Ustyurt plateau in Kazakhstan. Hybridisation seems to continue in the first four areas, where individuals of both species penetrate into the hybrid zones. In Kazakhstan there is no geneflow from melanoleuca into the hybrid zone anymore’.

We had some discussion about the bird already and have send the pics to Andrea Corso and Magnuss Ullman for comments (see Magnus’s great paper on the separation of Western and Eastern Black-eared Wheatears in Dutch Birding 2003: 2), which were both very helpful. The option hybrid Eastern Black-eared x Pied Wheatear seemed indeed the best one but I am still amazed about the appearance of this bird!

Does anybody know records in W-Europe of this hybrid-type or birds looking similar to this one?