Rig Recovery

I haven't had any overseas recoveries for a while but I received a recovery report the other day which was literally over the sea. The report was of a Redwing that had been found dead on an oil rig in the North Sea off Norway.



RY31120 Redwing
First Year      19/11/2018  Billinge Hill, Billinge, Merseyside.
Found dead  17/11/2019  Oil Rig Snorre B, Tampen, North Sea. 938km NNE

It wasn't freshly dead when found but is still likely to have reached the rig the same autumn as I wouldn't have thought a the body of a small thrush like a Redwing would last long on an exposed rig or remain unfound for very long either.

Late breeding

The breeding season is well and truly over for most birds in this part of the world but for at least one species it is not over yet. I was on the phone to my broadband provider at lunchtime today when I noticed a juvenile Woodpigeon on the privet hedge in the front garden and it appeared to be a young juvenile at that. The phone call quickly became the least of my concerns and I grabbed my camera and hastily took a few record shots through the window.

The original Boaty McBoatface.
Juvenile Woodpigeons have a wide almost boat shaped bill which helps them take pigeon milk, a crop secretion they are fed on, from their parents. 

You can see it had already replaced a few feathers on the head and the shoulder of its wings but that could have started immediately on fledging or even before it left the nest. Juveniles of some species start moulting before they leave the nest and this can be accelerated later in the season.

It quivered its wings from time to time which immediately suggested it was trying to solicit food from a parent and then I noticed an adult Woodpigeon a couple of metres away on the bird bath. The adult Woodpigeon then joined the juvenile and started to feed it. There is nothing subtle about an adult Woodpigeon feeding a juvenile and it often looks like a tussle and a trial of strength.

Get in there.

Woodpigeons have quite a long breeding season which can start as early as February and can extend into November and even December, although there can be some variation between years, regions and habitats. While this record of late breeding isn't without precedent for Woodpigeons it is certainly the latest I have recorded locally and for my garden in particular. Woodpigeons are one of the few species that are on the up and have benefitted from both garden feeding and some changes in agricultural practices.

Black-headed Gulls - old and new.

A few days ago (26/10/19) I went to feed the Black-headed Gulls at Orrell Water Park to check for ringed birds and one of the first to come to the bread had a metal ring on the right leg. I quickly identified it as the German ringed bird from the Hiddensee scheme that has wintered at the park each year since 2012. It has been recorded on over 90 occasions and is usually present from October to late February or early March. It appeared to be the only ringed gull present and I had almost run out of bread when a colour-ringed bird joined the 40 or so gulls present. It had a yellow colour-ring inscribed with the code T3WA on the right leg and a metal ring on the left. I hadn't seen this this particular individual before and had no idea where it had been ringed.

On getting home I checked the cr-birding website (link here) and quickly found that T3WA was a Polish ringed bird. I submitted details of the sighting on the Polish ringing scheme website and received details of where it was ringed the next day. It had been ringed on 17/06/2019 in central Poland at Skoki Duze, Kujawsko-Pomorskie, which is 1472km east of Orrell Water Park.

I didn't have my camera with me that first day but I have photographed both birds since.

DEH IA141745 photographed 27/10/2019

DEH IA141745 photographed 27/10/2019

T3WA photographed 30/10/2019

T3WA photographed 30/10/2019

Map to be added in due course.

Yellow-browed Warbler

I have not had time for blogging over the past few months but I have not totally given up on the idea of reviving it, yet. I hope to post some monthly summaries by way of a catch up sooner or later but in the meantime here is an image of a Yellow-browed Warbler that was ringed at Billinge yesterday (08/10/2019).

Yellow-browed Warbler 08/10/2019 © P J Alker

It is the 6th to be caught since ringing started at the site in 2014 and follows one that first year, another in 2015 and 3 in 2016. One was heard and seen briefly in 2017 but there were no records last year, although coverage in 2017 was less than in previous years. Yellow-browed Warblers may not be the rarity or scarcity they once were but they haven't lost any of their appeal or magic because of that.

It was a relatively quiet morning in all other respects with a totals of just 20 new birds and 1 retrap, although a first-year male Sparrowhawk did liven things up a bit and was the first to be ringed this autumn. 

Ringing totals (retraps in brackets) were: Sparrowhawk 1, Blue Tit 3, Coal Tit 2, Great Tit (1), Goldcrest 1, Long-tailed Tit 1, Yellow-browed Warbler 1, Blackbird 2, Redwing 5, Song Thrush 3, Bullfinch 1.

Billinge: 6th to 22nd April

I have been up to the ringing site at Billinge twelve times since 6th April but the catches have been quite small, hence the lack of blog posts about individual visits.  While the catches have been small they haven't been without interest and what you don't catch can be as important as what you do, or at least that is what I tell myself.

It looks like being another poor spring for Redpoll passage but that is hardly surprising as last autumn was very poor for Redpolls going south so a poor showing the following spring is no big surprise. Having said that you have to put the effort in to find out and I can certainly say I have put the effort in with only 18 Lesser Redpolls caught over twelve visits. One of the Redpolls caught on 10/04/2019 was a retrap that had been ringed at the site on 13/08/2017 as an adult female so perhaps a bird that breeds not too far away.

The most interesting Redpoll, for me at least, was a little adult male caught yesterday (21/04/2019). I say little as its wing length was 69mm which is fairly small or very small for a male of any race. We still don't know what to do with Redpoll species and races because they don't play by the rules as we would like to apply them. If my understanding is correct they should all be lumped at a genetic level, every last one of them, into one species because they are not distinct enough genetically despite their varying appearance. Arctic, Common, Lesser or whatever you want to call them they are all far more similar on the inside than they appear on the outside but that is what makes them even more fascinating. While they may be similar on the inside the difference on the outside largely determines where they will breed and that is why we like them so much.

A bit or quite a bit greyer than your typical Lesser and probably breeds well north of Billinge.

Broad white fringes to the greater coverts, tertials and inner webs of tail feathers.
A touch of tram lines up the mantle too.

Broad white fringes to the greater coverts and tertials.

Broad white fringes to inner webs of tail feathers.

Unstreaked under-tail coverts which is normally a feature of Arctic Redpolls.

Pure white, unstreaked, under-tail coverts, including the feather shafts. If you hadn't seen the rest of the bird you could be thinking Arctic Redpoll. I have seen Lesser types like this before so not as exceptional as it may appear.

The first Willow Warbler was noted on the 6th and it was good to find that 9 of the 20 that were caught between the 10th and 22nd were retraps. Of the retraps one was originally ringed in 2016 and eight were originally ringed in 2017. On the other hand Chiffchaffs have been thin on the ground this spring with only 3 caught but all were retraps - one from 2017 and two from 2018. Blackcaps have put in a pretty good showing so far with 12 caught - 10 new, 1 retrap and 1 control. The retrap was ringed as a first-year in August 2017 and the control was ringed 16 km away at Woolston Eyes in April 2018.

Unusual captures were a pair of Mistle Thrushes that found their way into one of the nets on the 16th and were a first to be ringed at the site. However, the highlight of the period, and what made the effort worthwhile, was the capture of six Tree Pipits with the first caught on the 13th.

Tree Pipit 19/04/2019

Tree Pipit 21/04/2019

The twelve visits yielded 54 new birds, 18 retraps and 1 control as follows (retraps in brackets): Lesser Redpoll 17 (1); Willow Warbler 11 (9); Chiffchaff  (3); Goldcrest 2 (1); Blackicap 10 (1) +1 control; Robin 3; Long-tailed Tit (1); Tree Pipit 6; Mistle Thrush 2; Bullfinch 1 (1); Dunnock 1; Yellowhammer 1; Willow Tit (1).

Rapid Goldfinch movement.

Earlier this month, in a blog post titled 'fatties', I mentioned catching some Goldfinches at Crawford that had significant fat deposits. I went on to say that they were migrants that would be heading much further north to breed and presumably to somewhere in Scotland or Northern Ireland. Since then I have caught other Goldfinches at Crawford with varying amounts of fat and I recently received a recovery report for one of them. Goldfinch ACF5670 was ringed at Crawford on 07/04/2019 at 09:20 and was subsequently caught by a ringer in Leswalt, Stranraer, Dumfries and Galloway just 2 days later on 09/04/2019 at 14:00.

It was a small female that wasn't particularly fat and weighed 15.2g at the time it was ringed and subsequently weighed 13.9g when it was recaptured at Leswalt. The weight difference of 1.3g gives some indication of how much fat it used to make the journey. The straight line distance from Crawford to Leswalt is 219 km but most of that direct route is over the sea, as can be seen from the map. Goldfinches generally avoid making long sea crossings and migrate overland as much as possible so it is unlikely to have taken the shortest direct route. If this bird took an overland route to Leswalt it will have travelled around 300km and possibly quite a bit further than that if it followed the convoluted coast of Northwest England and Southwest Scotland, even with a bit of a shortcut across an estuary here and there. There is also the possibility that it took a relatively direct route via the Isle of Man and there have been some recoveries that make that a realistic option but it still involves quite long sea crossings. One thing is sure it is an interesting movement for its speed whatever route was actually taken.





Goldfinch (Carduelis carduelis) Ring no: ACF5670
First-year Female   07-04-2019  Crawford, near Up Holland, Lancashire, England
Caught by ringer    09-04-2019   Leswalt, Stranraer, Dumfries and Galloway, Scotland
Duration: 2 days Distance: 219 km Direction: 317deg (NW)

11/04/2018: Ivy berry Blackcaps and continental Song Thrush.

I went up to Billinge first thing but there wasn't much doing so I packed up early and went to Crawford to top up the feeders. As I had my ringing gear with me I decided to put a net up there for an hour and as things turned out I am certainly glad that I did. There weren't many birds coming to the feeders, at least not while I was there, but the ivy berries worked their magic and I caught 6 new Blackcaps, all males. These 6 Blackcaps came hot on the heels of 5 that were caught at the site on the 7th and made me wonder how many have taken advantage of this particular abundance of ivy berries so far this spring or will do so while the they last.

Some parts of the ivy have been stripped of their berries but there are plenty left.

 Today's 6 Blackcaps came hot on the heels of 5 caught at the site on the 7th. Everyone is familiar with concentrations of birds on berries in autumn but less so with returning birds in spring. 

While it was good to catch the Blackcaps the highlight, for me least, was catching 2 Song Thrush as one of them was a small and very grey individual of the continental race (T. p. philomelos).

Continental Song Thrushes don't get any greyer than this one.

I would put money on this bird originating from a long way east. Song Thrush of the British race (T. p. clarkei) are much browner and are generally bigger.

There wasn't a hint of warm brown anywhere in its plumage.

Ringing totals (retraps in brackets) for 11/04/ 2019 were: Blue Tit 1; Long-tailed Tit (1); Blackcap 6; Blackbird (2); Song Thrush 2; Dunnock (1) ;Chaffinch (1).

Unexpected Blackcaps

I had a bit of a lie in today because the forecast was for heavily overcast conditions and little or no breeze that would last throughout morning. Luckily the forecast looked like it was going to hold true and I headed off to the baited site at Crawford at 8:00am under a completely grey sky and with little or no breeze to speak of. I didn't go earlier as there doesn't seem to be any advantage in setting up at dawn at this site now the days are much longer and had I thought the conditions would have remained the same throughout the day I would have opted for another afternoon visit.

First job was topping up the feeders and judging by how much the food had gone down since they were filled on Friday they were still being well used. I quickly set up the usual 18m net and I didn't have long to wait before the first bird was caught. There were a few Goldfinches and Tree Sparrows around but the first bird caught turned out to be a Blackcap. One had been singing while I was setting up and I assumed it was the bird I had first heard a few days ago (on the 3rd). A pair normally breed at the site so a singing Blackcap wasn't unexpected and nor was catching it. However, I didn't expect that 5 of the total of 20 birds caught over the next 3 hours would be Blackcaps (4 males and 1 female).

Male Blackcap

Female Blackcap

Looking at other blogs and sightings reports there appears to have been a bit of an influx of Blackcaps into the region overnight and it is likely that some of the Crawford birds fall into that category. The glut of ivy berries in the hedge by the feeders probably helped by providing a good refuelling point for recently arrived migrants.

The rest of the catch was pretty much as expected in terms of species but wasn't without interest. Two of the Goldfinches were fat with the heaviest weighing 19.7g which was 5.3g heavier than the lightest Goldfinch caught. The retrap Tree Sparrow was interesting as it was the first one from a previous year and was originally ringed as a breeding female on 9th June 2016. It was also interesting because of the state of its plumage. It basically looked like it had been attacked by a mad hairdresser for want of a better description. Many of the barbs of the feathers of the underparts appeared to have broken off and other feathers were similarly affected to a lesser degree. As to the cause I have no idea but I have caught Blue Tits that were similarly affected in the past.

Female Tree Sparrow S144976

A close up of the junction between the affected and the seemingly unaffected feathers.

Many of the wing feathers had a ragged edge.

The tail was in a poor state, the breakages didn't follow any fault lines and appeared to be quite random. It is as if the feathers have become brittle and the breakages happened during preening and that is perhaps why the head and neck appear to be the least affected.

Ringing totals (retraps in brackets) for 07/04/2019 were: Blue Tit 1; Great Tit 1; Blackcap 5; Blackbird 1; Tree Sparrow 3 (1); Robin 1; Chaffinch 1; Goldfinch 4(2).

Fatties

I hadn't expected to do any ringing today but I had planned to go to the baited site at Crawford in the afternoon to top up the feeders.  As I was getting ready to go the wind dropped away completely so I decided to take advantage of the calm conditions and took my ringing gear too. It was 3pm by the time I got to the site and I quickly set up an 18m net after topping up the feeders. There were plenty of Goldfinches and Tree Sparrows around and first birds were caught as I walked away from the net.

A busy little session followed with 27 new birds and 2 retraps caught during the 2 hours the calm conditions lasted. It was interesting that 4 of the 10 Goldfinches caught were very fat and had bulging fat deposits in the tracheal pit and over the abdomen; these birds will be migrants that will be heading much further north and presumably to somewhere in Scotland or Northern Ireland to breed. One of the Blackbirds (a 2cy female) was similarly very fat and weighed a whopping 126.7g. A lean Blackbird weighs around 90g so this bird will have been carrying in the region of 35 to 40g of fat and will be migrating back to Scandinavia or somewhere further east fairly soon.

Female Blackbird

Blowing back the feathers reveals the tracheal pit which is normally deeply concave in a bird that isn't carrying much or any fat but has been completely filled with fat and is bulging in this individual.

This slightly more angled view shows the yellow fat is bulging by several mm and overlaps the pink breast muscles. The abdomen was similarly full of and covered in fat. This bird must be at or very close to the point where it is ready to migrate and it is likely to set off on the next suitable night.

Ivy Berries.
The hedge on one side of the ringing site is full of ivy which is currently covered in ripe berries. These berries help migrant Blackbirds fatten up in readiness for the long journey back to their breeding grounds.

A Blackbird ringed at Crawford in the winter of 2016/17 was caught by ringers on the island of Utsira, off the coast of Norway, in spring last year and gives an indication of where today's fat Blackbird could be heading in the coming days.

Blackbird (Turdus merula)   Ring no: LK25293
Ringing details
First year female   29-NOV-2016   Crawford, near Up Holland Lancashire, England
Finding details
Caught by ringer   29-MAR-2018   Sore Merkeskog, Utsira, Rogaland, Norway
Duration: 485 days Distance: 795 km Direction: 37deg (NE)


Ringing totals (retraps in brackets) for 03/04/2019 were: Collared Dove 1; Coal Tit 1; Song Thrush 1; Blackbird 4; Tree Sparrow 8; Robin 1 (1); Chaffinch (1); Greenfinch 1; Goldfinch 10.

Uncommon Common Quaker

I haven't got round to running a moth trap in the garden this year, or anywhere else for that matter, but moths haven't slipped my attention altogether. My mothing instincts instantly kicked in when I came across this unusual individual on a galvanised bin at a manufacturing site on Friday (29/03/2019). It is fair to say it was hard to miss as it was doing a very poor job of looking camouflaged and its unusual appearance only added to its stand out appearance.

My excitement drew some bemused attention from people working nearby but I managed to explain my interest in the moth while taking a few photographs with my phone. If you are not into moths you will wonder what my excitement was about especially as Common Quaker is a widespread and relatively common spring species. Whilst the species displays some slight variation in ground colour individuals are normally evenly coloured which is what makes this example so exceptional.

The photo is a bit over exposed but there is no doubting the symmetrical and strongly demarcated dark brown distal portion of the wings.

The big question that an individual like this draws, especially given the finding location, is whether it is a natural aberration or has it been caused by contact with some chemical. The simple answer is I don't know but the one thing I find striking is the symmetry. The effect appears to be far too symmetrical and well demarcated for some random contact with a chemical to be the cause but then I am no expert. At the end of the day this is an uncommon Common Quaker compared to the thousands I have seen over the years.

Stockamsel: a name to conjure with.

My use of the term ‘Stockamsel’ and or the associated images of Blackbirds usually prompts some feedback and discussion so I thought I would give the subject a bit more of an airing. I should start by saying ‘Stockamsel’ is not a valid term as such; however, historic misconceptions and misinterpretations have generally led to it being associated with first-year male Blackbirds that have a distinct plumage type. They are also supposed to originate in a particular geographic region and that idea has persisted to a greater or lesser degree into the modern era.

I have previously mentioned that there is an illustration of a ‘Stockamsel’ type Blackbird in the Handbook of the Birds of Europe, the Middle East and Africa (BWP for short) that was published as recently as 1988. In that authoritative work the plate of Blackbirds shows a dark-billed individual with quite scaly underparts and captions it: ‘first adult male (autumn) ‘stockamsel’ variety’ so it is hardly surprising the term still has some traction, although there was no explanation the text for its inclusion. However, the term 'Stockamsel' does get a mention in the text of the Helm Guide to Bird Identification (Vinicombe et al)  that was published in 2014. In the section covering Ring Ouzel and Blackird and under the sub-heading 'Abberant Blackbirds' it states 'Confusion could also arise with first-winter male Blackbirds of the so-called 'stockamsel' type (from Germany and Poland) which have a dull bill and eye ring, browner wings, a paler chin, and heavy pale fringing to the underparts feathers' but note the qualified use of the term by referring to it as a so-called type.

I am no expert on the origin of the term ‘Stockamsel’ or how it was originally applied but the ‘amsel’ bit is easy as it is German for Blackbird. It would appear that ‘Stockamsel’ is simply an alternate/historic German name for Blackbird and is similar to how we, in the UK, have used Hedge Sparrow as a name for Dunnock. Whether it was originally meant to be used for birds with a particular distinctive appearance has probably been lost through the mists of time and the notion that Stockamsel type Blackbirds are of continental origin seems to have largely come from the origin of the word and not much else.

To what extent I am right or wrong about the origins of the term 'Stockamsel' doesn’t really matter but like others I have used it for those first-autumn/early winter male Blackbirds that are quite female like and often scaly in appearance. I have also speculated about their origins because there has been the notion that birds with that type of appearance are more likely to be continental.

I did stretch my use of the term in my last post as all the Blackbirds had yellow bills but I did say forget the bill in one of the captions as each of those birds would have looked quite female like with an all dark bill, as would have been likely up to the turn of the year. I also commented on their possible origin and considered local origin as likely as any. So if I have confused anyone or added to the centuries old misunderstandings about what a Stockamsel Blackbird actually is then I hope this blog post goes some way to clearing that up. Stockamsel is a term that probably should be confined to history but I don’t regret using it for drawing attention to first-year male Blackbirds with a female-like appearance, which was the real point.

Blackbirds are common birds and often don’t get a second look and being sexually dimorphic they are generally considered easy to sex, especially in the hand, but that is not always the case. It is worth having another look at the images of the bird that first tempted me to use the term ‘Stockamsel’.

This bird was caught 10th December 2016 and got me thinking about its sex as I was taking it out of the net. It certainly seems to fit the brief description of a 'Stockamsel' type given in the Helm Guide (Vinicombe et al).

The juvenile feathers of the tail were all brown. The significance of the tail is that some ringers sex juvenile Blackbirds on the basis of the tail colour and while it may be reasonably safe to sex those juveniles with a particularly black tail as male I don't think it would be appropriate to sex any juveniles as females using tail colour.

The wing was generally brown with the new greater coverts and median coverts being the darkest feathers and in this image looking blackish compared to the adjacent feathers but they still had a hint of brown and we far from glossy black.

 The images don't quite do justice to how brown the bird actually looked in the hand and while there is no doubt about the age of this bird its sex is less straightforward. I came to the conclusion that this was a first-winter male but had no way of verifying that.

So, hopefully, I have explained my use of the term 'Stockamsel' but the real interest lies in the variability of first-year male Blackbirds and those with a scaly and more female-like appearance in particular. I don't hold with the idea that it means they are necessarily of continental origin and more likely to come from Germany and Poland but they are interesting nevertheless.




References:
Cramp, S., ed. (1988) The Birds of the Western Palearctic, Vol. 5. Oxford University Press, Oxford
Vinicombe, K., Harris, A., Tucker, L., (2014) The Helm Guide to Bird Identification, page 323, Bloomsbury Publishing, London.

Crawford 08/03/2019: more Goldfinches and some dodgy looking Blackbirds

The weather has been pretty poor for mist-netting recently and the forecast looks even worse for next week so I decided to make the most of a brief weather window on Friday morning. A weak ridge of high pressure provided near perfect mist netting conditions for a few hours and, luckily, I was able to rearrange other commitments to take advantage of it.

The ringing site is baited every two or three days with the aim of ensuring food is never allowed to run out or run too low and ringing visits are generally limited to once per week or less, depending on the weather. As a general rule I would rather skip a week or two when it comes to ringing visits than try mist-netting in suboptimal conditions. That approach paid off again on Friday morning as the 3 hour session with one 18m net resulted in a catch of 48 new birds and 11 retraps.

Goldfinches topped the totals yet again, although that is not surprising given the success the species is currently enjoying and the high proportion of nyger and sunflower hearts in the seed on offer, but on the other hand Yellowhammers have been absent full stop and Greenfinches had been absent prior to this visit. The 2 Greenfinches caught in this session were the only ones recorded which is a very poor showing given the site has been baited for well over a month now. Greenfinch populations have seen a massive decline nationally large due to disease (trichomonosis) and there doesn't appear to be any prospect of that situation improving any time soon, if anything their decline appears to be continuing.

I don't catch many Reed Buntings at the site (only 11 individuals over the past 5 years) so it was good to catch one and more so because it was a retrap. Interestingly this male Reed Bunting was originally ringed 3km away on Billinge Hill in September 2015 and was previously retrapped at Crawford in March 2016. Most of the other retraps were from recent visits but all 3 retrap Blue Tits were much older with one having been ringed as a juvenile in June 2014 and the other two were ringed as first-years in December 2015.

Retrap male Reed Bunting

The second Blackbird caught during the session was interesting in that it had an unusual plumage. It was a brownish individual but the orange-yellow bill was strongly suggestive of it being a male. Some first year male Blackbirds can have a female like plumage and these birds are often termed 'Stockamsel' types which I have blogged about before (link here). However, it also had some feathers with what could be termed a frosted or white appearance. These frosty looking feathers were asymmetrical in that more were present left wing than the right. The tail was also affected but there was a bit more symmetry in the appearance of the tail. 

The appearance of the head and neck was not dissimilar to an old adult (2CY+) female as female Blackbirds occasionally acquire a near full yellow or orange-yellow bill with age.

The right wing was more female like than male with some slight frosting to the inner secondaries. There were 3 old greater coverts which points to it being a first-year bird and  is part of my reasoning for thinking it is more likely to be a male as the bill is far too orange-yellow for it to be a first-year female.

The frosty effect was much more extensive on the left wing but it still looks brownish overall and generally a bit more like a female than a male. There is one old greater covert which is shorter and just visible by the 2 heavily frosted greater coverts so points to it being a first-year bird like the right wing. The asymmetry wasn't just in the frosting as there were 3 old greater coverts on the right wing and there was only 1 on the left.

The tail was interesting in that the shape of the feathers was not dissimilar to those of an adult by being quite square ended but there are some obvious fault bars and other structural issues. The right central tail feather was a bit more pointed than the left but in all other respects (colour and wear) they were the same so it didn't look like one had been replaced. The frosting affected the the end portions of the 3rd, 4th and 5th feathers on the right and 2nd,3rd and 4th on the left. The outermost (6th) tail feather on the left was being replaced but you can see from the part that has emerged from the sheath that it is a similar colour to the main part of the other tail feathers and isn't coming through jet black like a male. It suggests this bird's appearance will remain similar to how it is now with any difference being more to do with the freshness of the feathers as can be seen in the upper-tail coverts with the newer longest upper-tail covert being a darker blackish-brown compared to the old worn brown upper-tail coverts. So this bird may not get any or much blacker as it gets older

The term 'Stockamsel' is attributed to the naturalist Johann Andreas Naumann and was first used a couple of centuries ago and has been used in the literature occasionally since then for those first-year male Blackbirds that have a more female like plumage. There is also the possibility that some of these 'Stockamsel' type birds are actually intersex as they display a mixture of male and female characteristics. That doesn't appear to have been considered before and I don't know that it has ever been ruled out. I found an interesting blog post which touches on this subject relating to wildfowl and possible confusion between hybrids and intersex birds which is worth a read (link here). I am no expert so I will stick with calling these dodgy looking Blackbirds 'Stockamsel' types until some research is done that confirms their sex and establishes the cause or causes for their appearance.

Now one 'Stockamsel' type Blackbird in a ringing session is interesting but I ended up catching another two which is exceptional in my experience.The other two didn't have the white frosting but in other respects were similar. In my previous blog post on the subject I refer to two I caught in the garden just over a week apart and I commented that if such birds weren't supposed to be of continental origin you would have thought they came out of the same nest. Now I have caught 3 on the same day and at the same site I do think local origin and same parentage could be a real possibility. Perhaps 'Stockamsel' types can originate anywhere in the species range if both parents possess a particular gene. There was nothing about the wing lengths of the three birds to suggest they were of continental origin in fact 2 of the 3 had relatively short wing lengths which, if anything, suggests they were more likely to be of British origin but then the fact that they have aberrant plumages probably means we shouldn't try and read anything into their wing lengths. Catching 3 on the same day certainly seems to make the chances of any of them being intersex a bit less likely but it can't be ruled out entirely.

Stockamsel type number 2 appeared to have 4 old greater coverts although the 3 outer were paler and shorter than the 4th but the outer 4 were browner than the blacker and newer looking next 3 inner greater coverts. Aberrant plumages can make ageing feathers more difficult for a variety of reasons not least because feathers of different colour can wear differently and birds with plumage aberrations may not always moult in the normal way, we simply don't know or can't be 100% sure. The 3 black greater coverts help make this one look more like a male.

Overall the 2nd bird was a bit blacker than the first individual but it is certainly not your typical first year male Blackbird

As with the first bird it is the near full orange-yellow bill that draws the eye and makes it look more like a male. Forget the bill and the plumage is intermediate.

I didn't photograph the 3rd Stockamsel type as it was very similar to the 2nd plus I had quite a few other birds to deal with at the time. The main difference was that it only had one old greater covert plus it was slightly longer winged (the wing lengths of the three birds were 126mm, 129mm and 132mm if you were wondering). Bottom line I caught 3 Stockamsel types out a total of 6 Blackbirds trapped in one session which, as I said before, is exceptional in my experience.

I am sure there could be a PhD for some upcoming ornithologist or geneticist if they do some research into this phenomena. Are they all males with some female characteristics or females with some male characteristics or something in between? Is there more than one cause?  Do they originate more frequently in some parts of the species range than others? Is it purely a first-year phenomena and do they always conform to type with the first full moult or is it the fact that Stockamsel types are relatively rare that makes finding a Stockamsel type adult that much rarer? If anyone out there has more information or has answers to any of these questions then please get in touch as I would be interested to know.

Ringing totals (retraps in brackets) for 08/03/2019 were: Collared Dove 1; Coal Tit 1; Blue Tit (3); Great Tit 2; Long-tailed Tit (2); Blackbird 5 (1); House Sparrow 2; Tree Sparrow 5 (1); Dunnock 1 (1); Chaffinch 1; Greenfinch 2; Goldfinch 28 (2); Reed Bunting (1). A total of 48 new birds and 11 retraps.