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

I too can't get a Marsh Harrier out of the first pic. I've looked thru Raptors Of The World and it ain't in there.

John.

I'm inclined to go with the leucistic juv marshy myself - strangely it does come across as having a hint of Harris or Swainson's hawk about it but they don't really fit. Don't think it's some falconer's freak either. Tail comes across as a bit short for marsh? but other than that nothing really differs from a dark juv - compare the 3rd pic with the later pic of the marsh harrier - the shape and structure are very similar.

Cheers,
Andrew

AStevenson said:

I'm inclined to go with the leucistic juv marshy myself - strangely it does come across as having a hint of Harris or Swainson's hawk about it but they don't really fit. Don't think it's some falconer's freak either. Tail comes across as a bit short for marsh? but other than that nothing really differs from a dark juv - compare the 3rd pic with the later pic of the marsh harrier - the shape and structure are very similar.

Cheers,
Andrew

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I seem to remember reading somewhere that juvenile Marsh Harriers have a pale coloured head which tends to rule juv out in this case. For people still interested here are 3 more photos taken the same day. I went back down to Benacre this morning but there was no sign of this bird. As I said yesterday it was last seen heading south (towards Southwold). Any reports of strange looking raptors from Westwood marshes or Minsmere?

Just dropped in again. What an intriguing bird it is. But for an individual this weird, it's probably not enough to look for matches in Raptors of the World or rely on plumage features like normal head colouration- this is not a normal example.

On structure, length of legs and length/shape of tail especially, I'm still on Marsh H. Here's a nice M H pic for legs and tail:

http://www.flickr.com/photos/heizenberg/93894312/in/set-72057594057264918/


On age- well if nice grosser logs in, let's discuss. I might learn something. If nasty grosser logs in, forget it.

Well, I'm glad I wasn't the only one flummoxed.

For what it's worth, I think this could be a Marsh Harrier on structure. If it were MH, the aberrant plumage could affect perceived shape (which is why I never wear hoops!). If it is possible for a juv or female MH to lack ALL cream colouring on head or elsewhere, then the white patches do look typical of the kind of partial albinism I've often seen in crows, blackbirds etc. Is a bird with one type of plumage aberration more or less likely to have another, different aberration? What are the odds?

This is way beyond me and I am fascinated to discover the outcome from, hopefully, more field obs and better birders than me ruminating on it. Congrats on finding a puzzler. I can see this thread running to pages 3, 4, 5....

It is not a Harris' hawk. The Harris would have the yellow from the ceare continue all the way to the eye. Although a Harris' may have some white in the body it would still maintain the white terminal band on the tail.

If you look at the pics closely you will see the cheek patches visible that is characteristic of a Harrier and you would not see it in a Harris'.

Greg

I can see the feathering on the auriculars, but I don't think I wouldn't say they were cheek-patches. They are just as pronounced in the 4th photo as they are lacking in the 1st and second photo.
Also, look how thick necked and bull-headed this bird is in photo 1 and 2. Marsh Harriers don't look like that, although I'd concede that photo 4 makes it look much slimmer and harrier-like.
Perhaps it's just a case of it looking very un-harrier-like in the first photos, but more harrier-like in next series.
I don't know. Very tricky bird. I'd love to see it in the field.

Megaquetzal said:

I seem to remember reading somewhere that juvenile Marsh Harriers have a pale coloured head which tends to rule juv out in this case. For people still interested here are 3 more photos taken the same day. I went back down to Benacre this morning but there was no sign of this bird. As I said yesterday it was last seen heading south (towards Southwold). Any reports of strange looking raptors from Westwood marshes or Minsmere?

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At the risk of repeating myself and others, juv Marsh Harriers do not necessarily show cream heads and lesser coverts. Most do, but there are those that don't. I've seen several along the east coast and around The Wash this year. At the risk of opening a whole new can of worms, this is probably one of the reasons (note i say ONE of...) that so many Black Kite records are rejected in this country.

Frenchy said:

Birds don't grow new feathers underneath exsting ones,

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You could be right and I would have agreed with you until fairly recently. Note this shot on Surfbirds, for example:

Note the brand new secondaries that have just about reached the old juvenile feathers on this 2nd calendar Red Foot. This isn't the only example I have found.

However, I've had another look at the pics of the Benacre bird and I'm not as convinced as I was that there are new feathers. But still, to my eye it looks like there are some darker, fresher secondaries on this bird. I am probably wrong.

However, if this bird hasn't begun moult, then that could be a very strong argument for it being an escape as I believe captive birds are more likely not to undergo moult when they are supposed to. 2nd calendar to adult Marsh Harriers should have undergone remex moult by now.

This bird cannot be a juvenile - have a look at the Winterton Pallid Harrier shots on Surfbirds for a good example of how fresh and unworn juvenile large BOPs will look.

Anyway, back to the ID. This bird has primary fingers that appear to thin for Marsh Harrier. Marsh harrier has 'chunky' fingers that result in a 'hand' that is as broad as the 'arm'. In other words, the wings are broader and are as broad to the primary tips on Marsh Harrier whereas to my eye, the Benacre bird has a hand that narrows.

The Chestnut on the underparts looks just a little too reddish for Marsh Harrier. I've tried to find a Marsh Harrier via Google that matches this bird for colour and I can't find one. By all means prove me wrong. This is, after all, a very difficult bird to ID.

The shape of the body on the Benacre bird doesn't look right for a Harrier. It has a barrel-like body with a 'domed' back more like a buteo? Have a look on Google and again try to match the Benacre bird to other pics of Marsh Harrier.

I have found one species, so far, that could be a match for this bird. It shows white on the vent, a white throat and the underparts are a match for the colour on the Benacre bird, I feel. Try having a look at the 'intermediate' form of Swainsons Hawk (Sibley). This species can show considerable variability, it seems, and that could explain the white assymetrical blotches on the underwing etc.

Cheers,

Andy.

Ps: Nice Grosser.

That new set of pictures look fine for a partially leucistic Marsh Harrier to me. I don't think its at all safe to base aging on feather wear in a bird that has abberant plumage. Albino/leucistic birds often show very heavy wear.

Also I can't see anything out of keeping with Marsh Harrier in the wing-tip shape - see attached. There does appear to be a tendency for juvs to have wider primaries than adults however so perhaps it isn't a juv afterall

I was on the fence after the first set of pictures because the head looked a little buteo-ish.

Like others this has me puzzled. Having looked at the entire thread again & the new shots I'm more inclined to say wierd MH. But try this (as Real Grosser says this bird's body is really barrel-like) : Trace the outline of the bird so you can only see the outline & no colours. On one pic in particular the bird's body looks all wrong - with a big belly - & the arm looks narrow.
Having said all that I wonder if this is just a strange angle which gives this impression.
Also I think my previous crude measurements comments could be out re the leg length for the same reason.
Still undecided but I don't think this is a normal bird of any species. What do others think re the amount of wear on all the wing and tail feathers - seems abnormal to me?

Here are some Swainson's hawks, allegedly intermediate ones

http://www.rshantz.com/Animals/Birds/Hawks/Swainsons/20050717Swainsons02N.jpg
http://content.ornith.cornell.edu/UEWebApp/images/SW_6_S.jpg
http://content.ornith.cornell.edu/UEWebApp/images/SW_7_S.jpg
http://content.ornith.cornell.edu/UEWebApp/images/SW_9_S.jpg

You were answering my last point as I was making it Jane!

As Andy say´s above, and also notice the wrong wing formula, p1 being far to long for March, or any of the harriers, should fall approx. level with p6, that is to say if primaries are in the right shape and not in moult, which there seems to be no sign of here. Iris looks all dark like juveniles (except some males in 1cy) and older females which normally takes several years to develop pale iris. As far as I can see, the tail projection from the feet (pic1) is the only pro Marsh I can be sure of. You have of course the pale throat patch of Swainson´s but the Wing formula alone is wrong for Swainson´s!

http://www.pbase.com/clinton62/image/42300594

http://home.earthlink.net/~richditch/swainsonshawk.htm

Andy,s pic: (for primary positions)

http://digiscopingukbirds.homestead.com/2005/MarshHarrierDSC_1255.jpg

http://www.justbirds.org/Italia/Marsh harrier.jpg

An intriguing raptor!

JanJ

I've had a lash at finding Marsh Harriers in a similar pose to the Benacre bird to compare structure. Give the ad Male a full crop and its a pretty good match!

JANJ said:

As Andy say´s above, and also notice the wrong wing formula, p1 being far to long for March, or any of the harriers, should fall approx. level with p6, that is to say if primaries are in the right shape and not in moult, which there seems to be no sign of here.
JanJ

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I thought P1 was approx equal to P6....

edit: mind you the harder I look, the more assymetric the wings look!

JANJ said:

You have of course the pale throat patch of Swainson´s but the Wing formula alone is wrong for Swainson´s!

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I agree that the Swainson's line of thought is a distraction. It's a while since I last shared an RV park with one, but I do recall that they are compact, short legged and short-tailed fellas. Not built like our mystery bird at all.

As for aging, it was good to hear from nice grosser. I agree entirely that it looks tatty for a juvenile of any species. But it is such a difficult bird in other ways that I am not as ready as him to 100% rule out that its a juvenile.

I'm still on MH based on structure, with baffling features being piebaldness (but that's explicable) chunky head and body shape in some pics (troubling but variable) and apparent body colour (a bit odd, but I wonder whether a visit to photoshop would fix that).

Jane Turner said:

I've had a lash at finding Marsh Harriers in a similar pose to the Benacre bird to compare structure. Give the ad Male a full crop and its a pretty good match!

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OK. Now try matching a Marsh harrier to the first shot of the Benacre bird!

This bird is not a juv. Some examples of juvenile birds showing this kind of wear should be posted here by those who disagree with me.

See attached 'dark morph' Swainsons pic. What should the wing formula be for Swainsons?

I'm not convinced it is a Swainsons but it seems to be the closest match plumage-wise.

Cheers,

Andy.

I'm not one for technical plumage details, but a Swainson's Hawk has very peculiar "pointy" wings, which this bird, whatever it is, has not.

For fun, check this Dutch leucistic Common Buzzard:
http://home.planet.nl/~jwhvdijk/bonte_buizerd.htm

Real Grosser on my list said:

OK. Now try matching a Marsh harrier to the first shot of the Benacre bird!

This bird is not a juv. Some examples of juvenile birds showing this kind of wear should be posted here by those who disagree with me.

See attached 'dark morph' Swainsons pic. What should the wing formula be for Swainsons?

I'm not convinced it is a Swainsons but it seems to be the closest match plumage-wise.

Cheers,

Andy.

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Wing formula for Swainson´s is shown in #54, providing that Swainson´s isn´t in wing moult which could alter the formula.

JanJ