Unstreaked Acro in London..... (1 Viewer)

KenM · Dec 4, 2014

Jane Turner said:
and this photo

http://www.birdforum.net/attachment.php?attachmentid=524348&d=1417712846

shows again just how much of the contour feathers (and primary tips) are worn away

It's not the variable biometrics, or extent of wear that concern...it's the consistency under most lighting conditions of the base tones to "uppers and unders" hence the fuscus shout.

I'm not surprised that you haven't seen this level of abrasion before...after all how often do we see December RW?

Bismarck Honeyeater · Dec 4, 2014

Jane Turner said:
Only just seen this.......what does it sound like?

Acro-like churr

Bismarck Honeyeater · Dec 4, 2014

KenM said:
I'm not surprised that you haven't seen this level of abrasion before...after all how often do we see December RW?

Not often, though my latest is the 7th December and that was initially thought to be a Blyth's Reed Warbler.

After the 7th I will go and have another look, to get a late date if nothing else. I suspect as others have said it will take some majorly good photos or sound recordings to progress further.

York_birder_08 · Dec 4, 2014

KenM said:
Any faecal sample would have to be obtained from it's preferred habitat, wading through a rat infested brook, liberally sprinkled with human deitrus, I think "arms length" images are my preferred route.

Having seen the brook in question, I think we need some sort of biohazard kit before we go in... i.e. Walter White in Breaking Bad.

York_birder_08 · Dec 4, 2014

These pictures really are excellent Ken, especially considering how elusive the bird can be. I think I've managed about 10 seconds worth of glimpses in four hours on the site, so I appreciate how much time and effort you've put in!

For anyone considering visiting from nearby, there's a great supporting cast for Greater London. Up to 2 Whitethroats, Stonechat, Grey Wagtail, Water Rail, and up to 3 Song Thrushes (really tough on the patch at the moment) in a single brook of about 25 metres. There's also a Kingfisher that regularly visits a nearby overhang on Dagenham Brook about 100 yards up Orient Way. Nothing fancy, but enough to keep you busy while waiting for the Acro.

KenM · Dec 5, 2014

York_birder_08 said:
These pictures really are excellent Ken, especially considering how elusive the bird can be. I think I've managed about 10 seconds worth of glimpses in four hours on the site, so I appreciate how much time and effort you've put in!

For anyone considering visiting from nearby, there's a great supporting cast for Greater London. Up to 2 Whitethroats, Stonechat, Grey Wagtail, Water Rail, and up to 3 Song Thrushes (really tough on the patch at the moment) in a single brook of about 25 metres. There's also a Kingfisher that regularly visits a nearby overhang on Dagenham Brook about 100 yards up Orient Way. Nothing fancy, but enough to keep you busy while waiting for the Acro.

Yes Adam, Saturday morning could be the "Big" tester?..as there is a forecast -4 overnight for London, an almost embarrassing 10 visits and 40 hours of obsessive hunting to get those shots! :t:

wolfbirder · Dec 5, 2014

I just love these Acros........... and another who would like to praise Ken for his images, your persistence has paid off.

I'm please Jane too felt that it looked short winged (in some images at least) and visually fairly evidently not a Marsh Warbler. Thought i was getting it all wrong!

Whatever it is, it is a fascinating individual. I know its not one, but it sometimes does look very BRW-like in some images. Sometimes one really does need to see a bird in the flesh.

KenM · Dec 6, 2014

wolfbirder said:
I just love these Acros........... and another who would like to praise Ken for his images, your persistence has paid off.

I'm please Jane too felt that it looked short winged (in some images at least) and visually fairly evidently not a Marsh Warbler. Thought i was getting it all wrong!

Whatever it is, it is a fascinating individual. I know its not one, but it sometimes does look very BRW-like in some images. Sometimes one really does need to see a bird in the flesh.

Thanks Nick, I think the real praise should go to Stuart Fisher (also finding in the area during recent years...Melodious and Yellow-browed Warblers).

For patchwork birding over the last few years this glorified ''Traffic Island'', probably one of the most incongruous places that one could imagine,
currently hosting amongst other things I suspect, the highest yield of ''December Trans-Saharan migrants'' along a 50metre stretch of brook within the UK.

I believe the ''Island effect'' (a mini self-contained ecosystem), isolated by the urban sprawl, rich in introduced/endemic shrubs and plants e.g.Japanese knotweed, Buddleia, Elder, Nettle, Giant Hogweed, Reed mace, etc.

All supporting diverse invertebrate species, to include Moorhen, Water Rail, Chiff Chaff, Wren, Robin, Chaffinch, Greenfinch, Goldfinch, House Sparrow, clouds of Starlings and Gulls overhead plus a healthy Brown Rat population.

Not ''yer average'' birding spot, but then...nor is the current yield!

Cheers

Jane Turner · Dec 6, 2014

wolfbirder said:
I just love these Acros........... and another who would like to praise Ken for his images, your persistence has paid off.

I'm please Jane too felt that it looked short winged (in some images at least) and visually fairly evidently not a Marsh Warbler. Thought i was getting it all wrong!

Whatever it is, it is a fascinating individual. I know its not one, but it sometimes does look very BRW-like in some images. Sometimes one really does need to see a bird in the flesh.

There appears to be a fair chunk of the primary tips missing (at least 4mm), judging by the shape of what you can see. The outer web should be longer then the inner for example. Plus it would be normal for slightly more wear to the longest primaries. That might account for its rather blunt wings.

This is a comparison to a fresh Marsh Warbler - chosen for the nice feather edges which make it easier to see the feather shapes. I've seen Blackcaps with even heavier wear.

wolfbirder · Dec 6, 2014

Thanks Jane, always an education when you contribute. Appreciated.

wolfbirder · Dec 7, 2014

I attach a useful link that looks at detail of African Reed Warbler, and scrolling down the link, Caspian Reed Warbler. The second bit in the link about Caspian RW looks at wing formula/emarginations, and plumage colouration, nostril shape, bill shape, supers etc.

//birdingbytrain.wordpress.com/tag/wing-formula/

KenM · Dec 8, 2014

wolfbirder said:
I attach a useful link that looks at detail of African Reed Warbler, and scrolling down the link, Caspian Reed Warbler. The second bit in the link about Caspian RW looks at wing formula/emarginations, and plumage colouration, nostril shape, bill shape, supers etc.

//birdingbytrain.wordpress.com/tag/wing-formula/

Many thanks Nick, the second part (the Caspian Reed Warbler link) was very informative, and as such might be considered supportive (certainly as far as tonal values are concerned).

Today I was able to get perhaps some marginally better shots, showing the wing formula in a more favourable light, allowing for a degree of movement either way, p2 appears to be aligned with p4.

In the shots where the uppers are looking ''darker'', this is due to the feathers being wet after bathing.

I don't know whether anymore images would advance or retard the case for fuscus, however, It's palette of transient tones...milky tea, sandy grey and occasionally olivey tints remain distinctly at odds with nominate scirpaceous, and as such for the duration of it's stay, might still be worth monitoring...weather permitting that is. Cheers

wolfbirder · Dec 10, 2014

KenM said:
Many thanks Nick, the second part (the Caspian Reed Warbler link) was very informative, and as such might be considered supportive (certainly as far as tonal values are concerned).

I thought that too, good luck with it Ken :t:

KenM · Dec 16, 2014

A few more shots from this ''flexible-winged/bodied un-streaked Acro''.

I'd always suspected that there was a degree of flexibility in the component parts of wing geometry regarding birds, most notably from my experience in raptors. However I was a little surprised, when I compared the emargination point on P3 in the first two shots. The first shot showing the ''mean average'' in (more or less alignment) with the bunched secondaries/tertials, and the second shot showing movement of the e-point further down the wing!

Presumably this level of ''movement'' is well known?

On a lighter note...it's ability to ''contort'' like a Wren, cost me several windows of opportunity, when I dismissed it as such (images 3 and 4).

Still there today, under-parts (allowing for wear) a constant silky white in most lights, with upper-parts ranging from pallid/sandy (when overcast) to grey/brown in brighter light.

Cheers

KenM · Dec 17, 2014

FWIW...here is a short video clip taken today under a grey neutral sky, (hoping it's not the last), as when I arrived, Council workmen with JCB type earth and vegetation ''levellers,'' were in the process of ''tidying'' up the site....again looking somewhat pallid and quite unlike Western Reed Warbler looking perhaps ''cosmetically'' more akin to Asian Desert/Booted Warbler? Cheers

http://youtu.be/PNyo5610vJU

CharlesFentiman · Dec 18, 2014

KenM said:
FWIW...here is a short video clip taken today under a grey neutral sky, (hoping it's not the last), as when I arrived, Council workmen with JCB type earth and vegetation ''levellers,'' were in the process of ''tidying'' up the site....again looking somewhat pallid and quite unlike Western Reed Warbler looking perhaps ''cosmetically'' more akin to Asian Desert/Booted Warbler? Cheers

http://youtu.be/PNyo5610vJU

Ken
Great video footage and trying to stop start it I almost managed a clear grab of the rump, but not quite. Are you able to get this from the original footage. The moving footage certainly does show the colouring and the whiteness of the underparts very well despite the thinness of the plumage!
Cheers
Charles

Mark Lew1s · Dec 18, 2014

While Kens efforts with this bird are to be commended, I'd be surprised if this record is going anywhere without further evidence. As far as we know, fuscus reeds cannot be identified in the field, right? I think for this to be confirmed as fuscus you're going to need some DNA, or other things that would aid a lab based ID.

Not that that should detract from peoples enjoyment of the bird of course - and I should also say that I'm not really condoning the trapping of this bird purely to get an ID.

Jane Turner · Dec 18, 2014

faeces would be enough for DNA.

KenM · Dec 18, 2014

CharlesFentiman said:
Ken
Great video footage and trying to stop start it I almost managed a clear grab of the rump, but not quite. Are you able to get this from the original footage. The moving footage certainly does show the colouring and the whiteness of the underparts very well despite the thinness of the plumage!
Cheers
Charles

Charles Hi, hope this shot suffices?

Mark Hi, Likewise...I'm certainly not advocating trapping either, irrespective of it's possible origins.

Hopefully ''disturbance and weather'' permitting, this bird might stay into the new year where over time, renewed feather growth might help to assist in establishing it's origins, and at the same time, determine a ''latest'' ever recorded overwintering UK Reed Warbler?

It would be interesting to know what ''plumage'' basis prompted the Germans/Dutch to (I assume) trap and DNA their respective birds...I would have thought not dissimilar cosmetics to the Leyton bird ?

Cheers

CharlesFentiman · Dec 18, 2014

Thanks Ken

When I saw the bird originally I thought it lacked any warmth to the rump, hence my request and the shot seems to confirm this. This does indeed seem at odds with the normal warmth to the rump that is exhibited by reed warbler. In fact the rump area does seem to have a colder colour than the rest of the upperparts. There seems to be just a hint of more warmth to the uppertail area though so the pallid rump seems to be completely at odds with expectation! But I haven't seen many wintering reed warblers.
I think we would all love it to drop some DNA in a convenient form but I would advise keeping out of the ditch - there could be all kinds of unwanted DNA down there!

Unstreaked Acro in London..... (1 Viewer)

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