Garden birds: winter 2020-21

It has been a very poor winter for birds in my garden, except for the Moorhen which stayed around until mid December, and it has not been for the lack of food on offer. The number of Goldfinches using the feeders has been low and only in single figures throughout. Perhaps the lockdowns have encouraged more people to feed birds in their gardens and this has provided species like Goldfinch with more options than in previous winters. It could also be because there is more natural food available this winter or a combination of the two. Siskins had been totally absent until recently with the first and only sighting of the winter being a fine adult male that visited the feeders yesterday. Use of garden feeders by Siskins is closely linked to availability of natural food supplies so it suggests there has been an abundance of natural food for that species, at least.

Adult male Siskin 09/03/2021

The rounded tail shape and uniform greater coverts and tertials make this Siskin easy to age as an adult (2CY+)

Blackbirds appear to have used the garden in slightly larger numbers with 26 being ringed over the course of the winter but that may be a consequence of the lockdowns and increased time spent catching and ringing Blackbirds rather than any real increase. One species that has seen a real increase in numbers is House Sparrow with up to a dozen visiting the feeders every day and a nice roost gathering in a neighbours conifer hedge. They had become very scarce in recent years so it is nice to see that they have made a bit of a comeback.

Also on a positive note it has been good to have a Blackcap visiting the feeders since the start of the year. It was an occasional visitor at first but has become a regular visitor over the past month or so. I assumed it was the same individual each time until 2 males were on the same feeder on 22nd February. I caught and colour-ringed one of them on 6th March and that bird has been seen in the garden numerous times each day since then but an unringed male was also present yesterday so perhaps there have been 2 birds all along.

Ringed male Blackcap 08/03/2021

Ringed male Blackcap 08/03/2021

Ringed male Blackcap 08/03/2021

Unringed male Blackcap 09/03/2021

Both Blackcaps are likely to stay around until late March by which time they will have fattened up and be ready to migrate to breeding areas in Europe or possibly elsewhere in the UK.

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.

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.

Crawford: 24/02/2019

Fog delayed the start of the session and strong sunshine brought it to a close but in the two and a half hours the tall hedgerow provided shade for the 18m net a decent total of 41 new birds and 5 retraps were caught. The catch was dominated by Goldfinches but a few more Tree Sparrows appear to have found the seed and 9 were caught along with a couple of House Sparrows. There was no sign of farmland species like Yellowhammer but they may still be finding enough food in the surrounding fields. It appears to be a similar story with Corn Bunting with birds thinly scattered across the adjacent farmland and some appearing to be back on territory.

Tree Sparrows have increased in this area in recent years but their distribution is patchy and they are still absent from some of their former haunts.

House Sparrows don't seem to be doing very well anywhere and while the steep decline in their numbers may have levelled off to some extent there doesn't seem to be any indication their numbers are likely to recover anytime soon. 

The current spell of unseasonably warm weather is clearly having an effect with a Linnet back on territory and singing at the ringing site; Chaffinch, Goldcrest and Song Thrush were also in full song. Spring was in the air for Dunnocks too with a lot of singing, wing flicking and chasing going on while a pair of Long-tailed Tits was prospecting for a nest site in the brambles. A reminder that we are still in winter came in the form of a male Chaffinch and a male Blackbird that were caught and found to have long wing lengths. Both of these birds were likely to be winter visitors from the continent with the colour of the underparts of the Chaffinch also pointing to a continental origin.

Ringing totals for 24/02/2019 were: Blue Tit 6 (4); Great Tit 2 (1); Blackbird 2; House Sparrow 2; Tree Sparrow 9; Dunnock 1; Chaffinch 2; Goldfinch 17.

8th March 2018 and it's snow joke.

A real dump of snow greeted me first thing this morning and it continued to snow for a good few hours. Some snow had been forecast but I had expected it to be wet sleety stuff and soon turn to rain but this was the real deal and covered everything in a good 3 to 4 inches of the white stuff before it finally stopped.

The view from the front door.

The view towards Orrell Water Park.

The snow clearly had an impact on the birds and the garden feeders were busier than they had been during the recent severe cold spell. We didn't get much snow then and many species, especially seed eaters, still had access to natural food sources and didn't seem pushed for food despite the very cold temperatures. This morning was a different story with the thick covering of snow limiting their feeding options and causing more birds to come to the feeders. 

Birds were queuing up to use the feeders and I have quite a few dotted around the garden.

The birds gather in the trees across the road from the garden before dropping down to feed.

Another group on its way in.

You could imagine this Goldfinch thinking 'Where did this lot come from'.

and this one was really shaking its head.

Some Goldfinches were clearly in pairs.

and another pair.

This male Chaffinch is in one of those 'what are you looking at' poses.

Looking at its tail shape this female Chaffinch is almost certainly an adult.

Female Chaffinch. I only included this photo because of the lump of snow on her head. The snow really did come down thick and fast.

It was nice to see a few more Greenfinches at the feeders but they are nowhere near as numerous as they used to be in the 'good old days', when Greenfinches were ten a penny.

Male Siskin

I was able to read part of the ring number on this female Siskin and it is not one that I have ringed. It will be really frustrating if I don't manage to catch her and establish where she has come from.

Three Pied Wagtails fed on the lawn below the feeders including this fine male. This bird has been a regular in the garden for much of this winter.

It won't be long before my Starling RAS starts. This adult male (A57) was originally ringed as a juvenile in June 2012.

Female Starling

Male Blackbird

Female Blackbird

Judging by the size of of its bib this Coal Tit is a male.

Woodpigeons haven't visited the garden much recently as they have been spending a lot of time feeding in a nearby field of oil seed rape.

The fat cakes have certainly helped this Goldcrest survive this winter.

Winter may not have released its grip just yet but give it another week and I should be writing posts about returning Chiffchaffs and other spring migrants. 

October 2017

A session at Billinge on the last day of the month produced a catch of 38 birds and was made up of 36 new birds, a retrap and a control. There were a few Goldcrests in every net round and they easily took top slot with 24 ringed. There weren't many thrushes moving but a Fieldfare found its way into a net and was the first to be ringed this autumn. Just a couple of Lesser Redpolls were caught but I was pleased to discover that one of them was a control (a bird ringed elsewhere) so it will be interesting to find out where that one has come from.

The control Lesser Redpoll was an adult female with ring number S341203.

Ringing totals (retraps/controls in brackets) for 31/10/17 were; Great Spotted Woodpecker 1; Goldcrest 24; Blue Tit 1; Great Tit 1 (1); Fieldfare 1; Redwing 7; Lesser Redpoll 1 (1).

A total of 746 birds were ringed at Billinge during October which is disappointing by that site's standards and is roughly half the total achieved in previous years. The main reason for this has been the lack of easterly winds which has resulted in much lower numbers of Redwings and Goldcrests passing through the site. However, Redwing and Goldcrest were still the most numerous species ringed by far and they topped the totals for the month with 292 and 259 respectively. Song Thrush came in third with 50 followed by Lesser Redpoll with 29 and Blackbird with 21. At the other end of the scale a Tawny Owl was only the second to be ringed at the site and a Firecrest was only the third ringing and sighting record of that species.

Billinge 22nd - 30th August 2017

I have managed to get out nearly every morning since my last post although some of the sessions were affected by fog, delayed and/or curtailed by showers or a strengthening breeze. A total of 200 birds were ringed and another 13 were retrapped over the period which is reasonable number given the mixed weather conditions and the limited number of nets used. There were no major surprises although sylvia warblers were in short supply throughout. Chiffchaffs took over from Willow Warblers as the most numerous warbler species as is usual in late August and all the less frequently caught species were what could be termed the usual suspects.

Species	New	Retrap	Species	New	Retrap
Goldcrest	18	1	Blackbird	2	0
Blue Tit	11	1	Song Thrush	2	0
Great Tit	15	2	Robin	5	0
Coal Tit	2	0	Redstart	3	0
Long-tailed Tit	0	3	Dunnock	1	0
Chiffchaff	54	3	Tree Sparrow	1	0
Willow Warbler	20	1	Grey Wagtail	2	0
Blackcap	8	0	Tree Pipit	9	0
Garden Warbler	0	1	Chaffinch	21	0
Grasshopper Warbler	1	0	Bullfinch	6	0
Reed Warbler	1	0	Greenfinch	3	0
Nuthatch	1	0	Linnet	3	0
Treecreeper	2	0	Goldfinch	5	0
Wren	1	1	Yellowhammer	3	0
Total for the period: 200 new birds and 13 retraps

Ringing highlights and noteworthy sightings were as follows:

22/08/17 - At least 12 Tree Pipits were on the move despite early fog and generally poor visibility but only 1 was ringed.

23/08/17 - This session was also affected by fog, some light drizzle and stayed quite murky once the fog cleared. It went so dark at one point birds went very quiet and some seemed to go to roost. However, this visit produce the first Redstart of the autumn, a 1cy female, amongst a catch of only 15 birds. At least 7 Tree Pipits headed south despite the conditions and 2 of them were caught. As the light drizzle stopped there was an unexpected sighting of a flock of 11 Dunlin flying low over the site and heading NNE, they may have been disorientated in the very murky conditions or simply been forced down by the very low cloud.

25/08/17 - Chiffchaffs really took over from Willow Warblers with ringing totals of 14 and 1 respectively. Another 2 Tree Pipits were ringed from a total of 6 recorded.

27/08/17 - Grey Wagtail passage got going with at least 4 passing over the site and 1 was ringed. Interestingly, similar movements were reported from sites across the country. Another 2 Tree Pipits were ringed from a total of 9 recorded. A juvenile Tree Sparrow was an unusual capture although a few had been recorded flying high over the site on the previous 2 days.

The first Grey Wagtail ringed this autumn

28/08/17 - A 1cy Reed Warbler was well away from its usual habitat and was only the 2nd to be ringed this autumn. This species is a scarce but regular autumn passage migrant at the site and 9 of the previous 13 records have been in the narrow period 23rd to 31st July with the remainder being on widespread dates in August. This session was also noteworthy for being the first of the autumn without a Willow Warbler being ringed or recorded.

1cy Reed Warbler

29/08/17 - A short, rain delayed session produced a Blackbird with an interesting plumage and not much else.

This 1cy male Blackbird is similar to what is sometimes referred to as the 'Stockamsel' variety. Had this bird been seen later in the autumn or during the winter it may have been thought to be of continental origin but there is virtually no chance of that in late August.

Its post-juvenile moult was almost complete.

It had a wing length of 131 mm which is towards the longer end of the range for locally bred birds but is not exceptional by any means.

1cy male Blackbird. A locally bred 'Stockamsel' type.

30/08/17 - Highlights were a Grasshopper Warbler and 2 Redstarts. At least 9 Tree Pipits were recorded 2 of which were caught. A few Grey Wagtails were on the move but only 1 was caught. There was a little flurry of Willow Warblers with 8 being ringed and this was more noteworthy as it followed a total absence of the species on the previous two days and was the only day that they outnumbered Chiffchaffs during the period.

1cy female Redstart 30/08/17

1cy male Redstart 30/08/17

S881488 adult Tree Pipit. This adult had retained 2 old lesser coverts. Apparently it is not uncommon to see this in adult Tree Pipits. There is certainly no doubt about the age of such birds. 

S881488 adult Tree Pipit. The tail feathers were much more rounded than those of the adults shown in my last post.

S881489 1cy Tree Pipit

S881489 1cy Tree Pipit. The 2nd outermost tail feather was missing on the right side of the tail. The shape of the tail is similar to the adult above but the contrast between the light and dark areas on the tail feathers isn't quite as strong. This difference in contrast can be a useful feature when ageing, according to some guides, although it isn't an easy difference to get to grips with and reportedly takes plenty of practice.

S881489 1cy Tree Pipit