Raptor with white bits, Benacre, Suffolk (1 Viewer)

valley boy said:

if this is a marsh harrier , doesnt the colour of the iris turn from brown(juvenile) to yellow?

Click to expand...

See post # 54.

JanJ

JANJ said:

See post # 54.

JanJ

Click to expand...

oops, :eek!: too busy looking at pics linked to your post

Real Grosser on my list said:

If you look at the close up shot posted earlier, you can see that the wear is extensive throughout all the secondaries and the inner primaries.

You MUST find other examples which show that wear of this nature can occur in a fresh juvenile. Go look at shots on Surfbirds and even posted here of juv Marsh and you'll see how fresh they all look. Without backing up this claim with examples, reference to text or other birds seen in the field it becomes worthless. Sorry.

Click to expand...

Andy,

For starters, I think that we simply disagree as to the extent of wear on these feathers. I have examined them in great detail and feel I have a pretty good sense of what is going on with them. To be sure there is some fraying, as I mentioned. But a good deal of the frayed effect is due to the pattern of pigment in the feather, not in the lack of feather barbules. Look at the images of the bird against a dark background and you can see the feathers are much more intact than they appear in the shot with a blue sky background. What fraying there is seems consistent to me for a bird that has been alive for four months spending much of that time pouncing on prey and otherwise bashing its wings against all manner of abrasive substrates. Juvenile feathers are the weakest to start with, and feathers lacking normal pigments are generally understood in ornithological circles to wear much more quickly than pigmented feathers. I cannot see why that seems so unreasonable a scenario.

Real Grosser on my list said:

My thinking is that this is an escaped bird which explains why it hasn't begun remex moult. I can provide many examples of birds in mid-late summer in remex moult if necessary that back this up. Revisit the Monties Harrier thread in Northern Ireland where plenty of pics of moulting birds were posted.

Have a look at the Red Foot shot I posted on this tread earlier which shows the effects of long term wear similar to that of the Benacre BOP.

Click to expand...

The falcon image is useful in the sense that it demonstrates the differential wear that I am referring to. It you look at the barred rectrices and remiges, it is the white areas that have worn away leaving just the pigmented portions of the feathers behind. I also note active molt centers and several darker, fresh feathers from the current molt.

An escaped bird may well explain the observed remex pattern, but since I disagree with the original premise that the bird is too worn to be a juvenile, I am stuck on how we go about ruling out a juvenile. All of the primaries and all of the secondaries are present and in the same state of wear and fading. To me, all of these feathers look to be of the same generation. Since older raptors often carry feathers from different molts, it would be helpful to identify which feathers you feel are newer and which ones are older, since I cannot see differences, I cannot begin to think about your point of view clearly. Again, I welcome your guidance with interpreting the image. So far, you have not convinced me that this bird is any older than 3-4 months.

Feather wear aside, there are aspects of plumage patterning that still need to be explained. While age determination is an important factor, there is still the actual identification to contend with. For me, I can see it being a juvenile Marsh Harrier, and once accepting that, a number of otherwise puzzling plumage features fall in to place. The shape comparisons that Jane has produced seem fairly compelling at least to the point that I cannot rule out a Marsh Harrier based on them. But I'm keeping an open mind about it.

Real Grosser on my list said:

Someone send this to Forsman........

Click to expand...

Agreed. I can see this one finding its way onto Jane's list of problematic species. We can all agree to disagree, but there is no need to be disrespectful of the viewpoints of others.

Chris

Chris Benesh said:

Andy,

We can all agree to disagree, but there is no need to be disrespectful of the viewpoints of others.

Chris

Click to expand...

I agree and I'm sorry to have upset you. I just find it frustrating when a view point, mine or otherwise, is dismissed on a whim without credible evidence.

Unfortunately this may be my last post for a day or four so I'll quickly say that the wear is also present on the darker areas of the Benacre bird including the tail. Most of the secondaries (pic 1) are perfectly normal, ie dark. This bird hasn't moulted for over a year and I tink I'm right in saying that they usually moult all their remiges so they should be same generation. That kind of feather damage doesn't happen in 3-4 months. By all means, prove me wrong!

The links provided by Jane are helpful but they don't necessarily prove much. For example, the juv Rook has shorter, stunted feathers that haven't grown properly: They are not worn (not frayed). 2 of the other birds are Adults and only the pale areas show abnormal wear which backs up your 'differential wear claim'. But as the darker feathers are also as worn on the Benacre bird, it shows that there isn't any differentiation evident now.

I still haven't found an image of another juvenile BOP showing this amount of wear. This bird is not a juvenile. Have a look at the image in Post 20.

I am a long way from being convinced that this bird can be Identified at present.

I've sent it to Forsman....

Have a good weekend!

I too fear this will be consigned to the unidentifiable bin but I do think there is enough there to say the abberant Marsh Harrier is the most likely option.

-It was acting like a MH and only when the pics showed white was the ID questioned.
-The seemingly incorrect wing formula/wing shape is matched by a perfectly normal Marsh Harrier.

BTW - have you sent all the photos to Dick Forsman, or just the one where it looks least like a Marsh Harrier?

Real Grosser on my list said:

But as the darker feathers are also as worn on the Benacre bird, it shows that there isn't any differentiation evident now.

Click to expand...

Have a good weekend too.

I think its entirely possible that the apparently worn darker feathers are white-tipped feathers minus their white tips. I recall that when aging Goldfinches by their tertial markings (eons ago) it was possible to see the shape of the marking though they were missing, by the shape of the hole left behind. The same was true of Redwings.

Real Grosser on my list said:

Most of the secondaries (pic 1) are perfectly normal, ie dark. This bird hasn't moulted for over a year and I tink I'm right in saying that they usually moult all their remiges so they should be same generation.

Click to expand...

I'm sure I'm not the only one who can see white in the secondaries? If you look away from the tips of the secondaries you can see pale/white patches on many of them. The absence of white towards the tips is because they're worn away (edit; cross-posted with Jane's latest).

If all of the remiges are of one generation then I still believe this is a 1cy bird. How many 2cy/2cy+ birds would have completed remex moult by mid-September? If it is a 1cy bird then it does seem very worn for this early in it's life. Further indication of captive origin maybe?

martin

Am wondering about the shape of this bird's face - to me, harriers have very forward-pointing eyes, slightly owl-like at a front view and in all plumage a lot of contrast between the ear coverts and the rest of the head.

The bird in question doesn't give me that "look" - rather subjective I know.

Real Grosser on my list said:

I agree and I'm sorry to have upset you. I just find it frustrating when a view point, mine or otherwise, is dismissed on a whim without credible evidence.

Click to expand...

Andy,

First off, have a good weekend, hopefully out looking at real birds!

This sort of debate can be downright exasperating sometimes. But at least were talking about the identity of a bird from a small series of photos, not any of life's much bigger, important issues.

Credible, in this instance, is in the mind of the beholder. In my mind, my position is quite credible, though to you it seems ludicrous. I have tried to argue why I disagree with you, not just pull some position out of the hat willy-nilly. After the explanations we might shake our heads because the other guy just didn't get it, but it is not for lack of trying. If you feel I did not TRY to explain myself, go back and reread my posts. You will find that I attempted to back up my viewpoint whether well founded or not. If I'm wrong, it would certainly not be the first time for me.

Real Grosser on my list said:

Most of the secondaries (pic 1) are perfectly normal, ie dark.

Click to expand...

If these shots are all of the same bird, then there is indeed some pale tipping to all of the secondaries. See attached shot with numbered remiges. I can see white tipping associated with each feather tip (though minimal on pp7-10). How I would interpret the first image is that those very white areas get lost in photographic effect because they shadowed gray against a light background. I would put a lot more weight in assessing the amount of white viewing against a dark background, as with photos #2, #3, and #4.

On the identification front, in looking again at picture #4, is there not a pretty evident Circus-type facial crescent visible? While it is not clear in all of the images, it seems to be clear in this one. It couldn't be a photographic artifact could it? If real, it should further the case that this is a Circus. There also seems to be a paler grayish flash at the base of pp9-10 consistent with that found on juvenile Marsh Harrier. That combined with unbarred remiges and rectrices, and tail and uppertail coverts similarly colored as in juvenile Marsh Harrier continues to suggest to me that this might be the most likely possibility.

Whatever the outcome of this discussion I think that everyone would agree that this is one weird bird well worthy of the debate it has received.

Chris

Chris Benesh said:

Circus-type facial crescent

Click to expand...

Aha, at least now I know the correct terminology :t:

pianoman said:

Aha, at least now I know the correct terminology :t:

Click to expand...

Hey Pianoman,

In North America, the feature is typically referred to as the facial disk. My coinage was in reference to the slightly paler, tawny border to the facial disk which happens to form a crescent. That part is probably not standard usage anywhere. I notice that Forsman does not speak specifically of a facial disk, but talks about cheeks bordered by a collar. So in his terminology, my crescent would be his collar. Sorry for the confusion.

Chris

Jane Turner said:

I love a challenge! This is the best I have found so far.

Click to expand...

I don't know if we are getting anywhere here but is it just me or does the top bird in Janes comparison post look even more buteo like. The lower MH looks a lot longer winged to my eyes.

John.

Hi all,

I didn't get the chance to look at this bird much over the weekend but I will concede that there is more white in the secondaries than I first thought.

However, I did look at 200+ images of medium to large juvenile BOPs and in September to November they all look immaculate.

I am so convinced that this bird isn't a juvenile that I'll twitch my next British lifer dressed as a banana if images can be found and posted here of medium to large sized juvenile BOPs that prove otherwise......

Cheers,

Andy.

Real Grosser on my list said:

Hi all,

I didn't get the chance to look at this bird much over the weekend but I will concede that there is more white in the secondaries than I first thought.

However, I did look at 200+ images of medium to large juvenile BOPs and in September to November they all look immaculate.

I am so convinced that this bird isn't a juvenile that I'll twitch my next British lifer dressed as a banana if images can be found and posted here of medium to large sized juvenile BOPs that prove otherwise......

Cheers,

Andy.

Click to expand...

Hello nice grosser.

I had a busy weekend too, but did manage to find a nice picture of an albino harrier with joyously unworn white secondaries...

http://www.omvirtuallythere.co.nz/category.asp?parent=10&category=10&CurPage=10

(with a rather nifty rotate function on the image..)

Real Grosser on my list said:

I am so convinced that this bird isn't a juvenile that I'll twitch my next British lifer dressed as a banana if images can be found and posted here of medium to large sized juvenile BOPs that prove otherwise.......

Click to expand...

You know that is almost worth the effort involved! Would you be taking pictures of said event if I was to find one?

The good news for both of us is that I'm tied up all this week!

Edit: Do you not accept that there could be unusual wear due to missing white tips?

and curses.... nearly - if only it were a juv!

http://www.somersetbirds.uko2.co.uk/images/5607 Black Kite.JPG

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... especially if its a worn juv (joke)

I can't see any reasnon to gainsay Rasmus and a few others

a leucistic / albinistic Marsh seems the most likely option. And just to wind up Andrew, I also think it could be a juv. with differential wear on the paler tips etc...

and feathers (AFAIK) grow from the 'follicles' of the previously dropped feather rather than over or under the one (to be) replaced.

Tim

I ll take a minor place in this.
You people are certain yet, it not to be buteo?
I am in for a Marsh Harrier; apart from the white plumage and the lack of yellowish feathers, the original plumage is okay with it.
The headcharacteristics, the wing action, the wing shape, the body shape and tail..

Jane Turner said:

You know that is almost worth the effort involved! Would you be taking pictures of said event if I was to find one?
[/url]

Click to expand...

Definitely! I'll even wear the outfit all next week on Shetland! But then I know it won't happen. There isn't an example on this planet of another large juv BOP showing this kind of wear in September of its 1st calendar year.

However, examples may exist on the planets that are inhabited by people who think this kind of extreme wear can occur on a bird that's just left the nest....



Andy.

ps - nice one Whiteback. Very funny!