Raptor with white bits, Benacre, Suffolk (4 Viewers)

[tittletattler]

I'll chuck in my four-penneth!
I have a video I took at Strumpshaw three years ago which is of an even odder Harrier!
Anyone interested in a still?

Yes please.

New thread?

 

[Jane Turner]

Any chance that you might accept that a partial albino juv raptor might have unusual an excessive wear to its white feathers Grosser...?

Schreiber, R. W., E. A. Schreiber, A. M. Peele*, and E. H. Burtt, Jr. 2005. Feather damage in an albino Great Frigatebird. Wilson Ornithological Society annual meeting. Beltsville - A juv Frigate bird rendered incapable of flying by excessive feather wear. Feather on feather and collision during flight airbourne particles being postulated as the source of damage.
http://www.cooper.org/COS/108_3/108_3abs24.pdf

Melanin and the abrasion resistence of feathers, Richard Bonser, The Condor 97:591-592
http://elibrary.unm.edu/sora/Condor/issues/v097n02/index.php


Are melanized feather barbs stronger? Michael Butler and Amy S. Johnson* Journal of Experimental Biology 207, 285-293 (2004)
http://jeb.biologists.org/cgi/content/full/207/2/285

I'll give Richard a poke and see if he fancies adding anything!

 

[tittletattler]

Melanin and the abrasion resistence of feathers, Richard Bonser, The Condor 97:591-592
http://elibrary.unm.edu/sora/Condor ... files/issues/v097n02/p0590-p0591.pdf

I think Richard mentioned this paper when I was out birding with him not so long ago!

I've had a very quick look at the links:

1) Frigatebird - wholly albino and no photographs! Doesn't mention secondaries.

2) I scanned the summary so forgive me if I'm wrong. Darker feathers are 39% stronger, yeah? So, the kind of wear shown by the Benacre bird could become obvious in about early Spring? Not when it's just left the nest?

3) Didn't read it. What's it say?

4) Look at the pale tips to the secondaries on the Pallid Harrier at Winterton. Why haven't these 'worn away' then? Do you want hundreds more examples? I can post them here?

Keep going! A trip to Mr 'Party Wear' on the high street is still a long way off.

Andy.

 

[Jane Turner]

A couple more...

Andy - if you are so unwilling to accept that partial albinism could result in unusual wear, then there really isn't much point reading these references.

That Frigate was flightless - thre may be no pictures (yet) but do you really think its flight feathers were in good nick?

 

[tittletattler]

A couple more...

Andy - if you are so unwilling to accept that partial albinism could result in unusual wear, then there really isn't much point reading these references.

That Frigate was flightless - thre may be no pictures (yet) but do you really think its flight feathers were in good nick?

I can accept that it can result in unusual wear but not to the extremes that you are suggesting in a slightly albino bird. The second link states about 10% extra wear, yeah? That's not extreme.

The wear on the Benacre bird is consistent with other BOPs that have suffered a year's worth of wear as already shown (see Red Foot pic).

I'm off to buy a paper for lunch. I won't be checking the prices in Mr 'Party Wear' as I walk past....

Cheers,

Andy.

 

[Jane Turner]

Darker feathers are 39% stronger, yeah? So, the kind of wear shown by the Benacre bird could become obvious in about early Spring? Not when it's just left the nest?

This bird could be as old as 4 months..... if its white flight feather and tail tips are 39% weaker than the normal feathers, it could have the equivalent of a year's wear already!

 

[tittletattler]

This bird could be as old as 4 months..... if its white flight feather and tail tips are 39% weaker than the normal feathers, it could have the equivalent of a year's wear already!

It would take 61% of the time to show the same wear that a very abraded (darker) bird would show. So, at least seven months(ish).

One of your links said 10% so that would make it about 10-11 months......

There is a chance, of course, that you may find that one example of an abraded large juv BOP and I could be watching a Blackburnian dressed as a yellow fruit. Even so, I will have proved the point that some people have failed to see and that is that the most obvious solution is usually the correct one. On Birdforum it takes just one person to suggest 'fantasy' as a solution and many others agree without any scientific evidence or references.

Think about: Someone posts a pic on Birdforum, one person states '1st for planet Earth' solution and many people agree without any evidence to support the claim. Is that not lunacy?

The Benacre bird is a not a juvenile.

Cheers,

Andy.

 

[Jane Turner]

Have you decided what species is is yet Andy?

 

[tittletattler]

Have you decided what species is is yet Andy?

No. I don't know what it is.

 

[Strandman]

No. I don't know what it is.

That's the easier (but not easy) bit. Exposed tarsus length and length/position of toes against a tail of that shape mean it has to be a harrier and if harrier, it has to be Marsh (leaving aside my foray into approximans, which was still a Marsh Harrier sub when last I saw one many years ago).

Explaining how a Marsh Harrier gets to look like this (and how long it takes to get like this..) is the hard bit.

 

[bitterntwisted]

I could be watching a Blackburnian dressed as a yellow fruit.

From some of your posts it seems you are not always above pedantry yourself, and as such I hope you will not mind me pointing out that the banana is not a fruit, since the banana plant is a herb, and not a tree.

Graham

 

[Frenchy]

Has Mr Forsman replied to you yet Andy?

 

[tittletattler]

Has Mr Forsman replied to you yet Andy?

No.

Banana is a herb?

"noun [C or U]
a long curved fruit with a yellow skin and soft, sweet white flesh inside:"

Is the plant a herb, but the fruit is a ....well....fruit?

 

[Jane Turner]

In the spirit of entente cordial

Is a banana a fruit or a herb?
Both. A banana is undoubtedly a fruit (containing the seeds of the plant, though since commercially grown banana plants are sterile, the seeds are reduced to little specks. However, the banana plant, though it is called a 'banana-tree' in popular usage, is technically regarded as a herbaceous plant (or 'herb'), not a tree, because the stem does not contain true woody tissue.

In the same vein I think it is fair to say that this level of wear is impossible on a normal (max 4 month old) juvenile raptor. It is also feasible that feather tip weakness in the abnormal white parts might lead to actual or apparent heavy wear to the tips of those feathers.

 

[Jane Turner]

Further:

Look at the flight shot from below: This bird is in moult and the newer feathers can be seen underneath the old broken feathers. The new feathers are almost as long as the old feathers.

This is not a bird 'of this year'.

I still can't see this - all the feathers appear to be the same age to me.... any chance of illustrating what you mean?

 

[Strandman]

I still can't see this - all the feathers appear to be the same age to me.... any chance of illustrating what you mean?

I took the point to relate to the dark brown wedges visible on the underside of the upper wing in particular on pic #2. On a neat and tidy bird..like a juvenile ha ha .. it should be fairly clear that these are formed by the overlap of the secondaries. But here it is much harder to be sure (at least from where I sit) what is going on. The darker areas form some unexpected and mysterious shapes. But I think these may be effects in part due to the demarcation with some paler brown towards the tip and in part to the generally disorganised state of the secondaries.

But of course I hasten to add that I do not presume to speak for grosser...

 

[Chris Benesh]

I took the point to relate to the dark brown wedges visible on the underside of the upper wing in particular on pic #2. On a neat and tidy bird..like a juvenile ha ha .. it should be fairly clear that these are formed by the overlap of the secondaries. But here it is much harder to be sure (at least from where I sit) what is going on. The darker areas form some unexpected and mysterious shapes. But I think these may be effects in part due to the demarcation with some paler brown towards the tip and in part to the generally disorganised state of the secondaries.

But of course I hasten to add that I do not presume to speak for grosser...

Hi All,

As white-back has pointed out, that is exactly what is going on with this bird. However, I think that Andy backed down from the molting bird position some time back in the thread, based on his more recent postings. On the topic of feather wear, I'll repeat myself again in stating that I think that the actual amount of feather wear visible on this bird is significantly less than the apparent wear. Check out the shapes of the tips of the remiges against a dark background. They are still mostly shaped like normal feathers, not like the tattered messes they appear to be in photo #1. There are those odd streaks of dark pigmented barbules that extend out to the tips of the feathers that break up their pattern, but there are still white, unpigmented barbules there. Don't Marsh Harriers spend a great deal of time crashing into marshland and such after prey? Certainly that behavior takes its toll on improperly pigmented feathers. And if a bird is four months old, it has already done a fair bit of pouncing.

There is a chance, of course, that you may find that one example of an abraded large juv BOP and I could be watching a Blackburnian dressed as a yellow fruit. Even so, I will have proved the point that some people have failed to see and that is that the most obvious solution is usually the correct one. On Birdforum it takes just one person to suggest 'fantasy' as a solution and many others agree without any scientific evidence or references.

Think about: Someone posts a pic on Birdforum, one person states '1st for planet Earth' solution and many people agree without any evidence to support the claim. Is that not lunacy?

The Benacre bird is a not a juvenile.

Andy, the time may be at hand for you to become less critical of the evidence which has been provided and more proactive about coming up with a better alternative. We seem to be stuck on the issue of whether this bird is a juvenile or not, when really, we are trying to work out its identity. Quite a bit has been posted about field marks that suggest the identity of the bird, and many of these marks are working toward the conclusion that this bird is a Marsh Harrier. Just suspend any notion of feather wear (assume for a moment we did not know the date at which this photo was taken), is not the simple solution that it is some sort of aberrant Marsh Harrier? Or is the simple solution that the bird is some crazy hybrid of captive origin for which no one has any prior experience with, that just happens to behave like a Marsh Harrier and share a number of plumage characteristics with that species? Perhaps the challenge to you should be to find an image on the internet of some Buteo that resembles this bird. It seems to me that you are the one who is advocating the 1st for planet Earth solution here, not anyone else. Again, this is a great example of where credible is not necessarily an objective term (is certainly isn't in global politics). I think this is the part where we all walk over to the nearest wall and bang our heads. I don't think that we are going to get to the same page anytime soon. That's cool though. It is a weird bird. Oh, and just in case they're out at the party shop, here are a couple of links that may ultimately prove helpful.

http://www.stage-fright.com/topbasuco.html
http://www.zoogstercostumes.com/landing/banana.php?source=Google-Banana

Chris

 

[Frenchy]

It would take 61% of the time to show the same wear that a very abraded (darker) bird would show. So, at least seven months(ish).

One of your links said 10% so that would make it about 10-11 months......

There is a chance, of course, that you may find that one example of an abraded large juv BOP and I could be watching a Blackburnian dressed as a yellow fruit. Even so, I will have proved the point that some people have failed to see and that is that the most obvious solution is usually the correct one. On Birdforum it takes just one person to suggest 'fantasy' as a solution and many others agree without any scientific evidence or references.

Think about: Someone posts a pic on Birdforum, one person states '1st for planet Earth' solution and many people agree without any evidence to support the claim. Is that not lunacy?

The Benacre bird is a not a juvenile.

Cheers,

Andy.

Do i take it that as the first person to say that this was basically a dark juv Marsh Harrier with some white bits way back in post #12, you're saying that i'm giving a fantasy identification? Also, what is the point you say you've proved? As much as you say we have not proved that its a leucistic Marsh Harrier, then what have you proved it to be?
My ID as a dark juv was based as much on the fact they are relatively frequent compared to dark adults (rare over here, slightly commoner the further east you go according to Forsman) than any detailed analysis of the feathers. While i agree with you that there is a massive amount of wear for a juvenile, this is no ordinary bird, and the lack of melanin has clearly affected the wear of the secondaries. The primaries look a lot more normal to me, with a good, fairly fresh appearance. Coincidently, they do not have any areas of leucism...

Just read Chris's excellent post above, and agree whole heartedly.

 

[Jane Turner]

Or is the simple solution that the bird is some crazy hybrid of captive origin for which no one has any prior experience with, that just happens to behave like a Marsh Harrier and share a number of plumage characteristics with that species? Perhaps the challenge to you should be to find an image on the internet of some Buteo that resembles this bird. It seems to me that you are the one who is advocating the 1st for planet Earth solution here, not anyone else.

I have to say I was thinking much the same. A bird was taken to be a Marsh Harrier, that is shaped like a Marsh Harrier, is most likely to be a Marsh Harrier. Especially when it has been demonstrated that partial albinism isn't even that uncommon in the species. Certainly more likely than a prviously undescribed hybrid.

Perhaps the sticking point is that if it is a Marsh Harrier, then it is most likely a juv based on soft parts and plumage. How common is moult suspension I wonder - I did pick up several references to moult suspension in albino birds when searching for papers on feather wear?

 

[bitterntwisted]

Is a banana a fruit or a herb? Both.

In botanical parlance a banana is not a fruit but a false berry. See http://en.wikipedia.org/wiki/False_berry. However, in common parlance it is a fruit and a very good fancy dress twitching outfit. I'll start a separate thread on HerbForum.net. Meanwhile, back to the Marsh Harrier.

Graham