Eagle for ID (2 Viewers)

[Jane Turner]

According to this link posted earlier:
http://www.bsaponline.org/litrev.html
"The gape of hastata extends well behind the eye, whereas that of clanga (and pomarina) does not".

On Sumit's photo, it goes to just below, but not behind, the eye, which suggests to me it is more likely to be clanga.

Michael
PS is anyone going to admit to ever having dropped a clanga over eagle ID? :king:

It looks pretty much bang on the middle of the eye to me too Michael...

However I couldn't help noticing this Importantly the gape is thicker and more fleshy; contrary to some of the literature it extends to the middle of the eye as in Greater Spotted

This would be so much less fun if there were some hard and fast rules about that Indian Spotted Eagles actually looked like

Addition

I've lightened the pic of the upper wing, which was in heavy shadow. It no longer looks like an adult bird. Assuming its GSE, it would be a 3rd cal year bird I'm guessing. I can't decided if the secondaries show any barring or not. I'm leaning towards not on the outer ones at least.

 

[Edward woodwood]

ok here's some relevant (I hope) from a brief e-mail discussion with expert Steve Parry re a possible article for an OBC Pub. Hope Steve doesn't mind....

It is certainly the case that there are many misidentifications...... hastata is probably very rare and its conservation status is desperately in need of critical
re-evaluation. They no longer appear to occur in many areas from which 19th century specimens were taken.

Separating juvenile hastata from clanga in the field is very easy, juv clanga are exceptionally distinctive. But adults are another matter, they basically just look brown in the field and that is largely it in terms of plumage!!! The relatively minor plumage differences between the two are absolutely consistent but relatively subtle and are probably difficult to spot in field conditions. Gape/head size, extensive 'lips',overall size and
vocalizations of hastata are probably the best criteria for field observers who have not examined museum specimens or live birds in the hand. Hastata are smaller than clanga but their skulls are the same size or actually
larger in sexwise comparisons- so they have a very different jizz. This is very obvious when you know what to look for.

There are probably also habitat differences between the two. Hastata seems to take mostly small mammals in dry(ish) woodland/savanna habitats whereas wintering clanga tend to wetter habitats. I think that most of the reports of hastata from jheels etc are probably wintering clanga hunting amphibians.

Available evidence also suggests that clanga may very rarely breed in India. This is controversial but some specimen evidence seems to support this. Another cause for concern are young A. rapax vindhiana - some of these have a 'spotted plumage' (quite unlike their African conspecifics) and are superficially similar in this respect to young hastata. They also have relatively large gapes. However, both hastata and clanga have very elongate legs and relatively small feet. They also have small, rounded external nares (nostrils) [as in your photo.] A. rapax vindhiana have slit-like nares, bigger
deeper bills and short thickish tarsi with relatively larger
feet. They also differ in a number of plumage traits. All three differ in size but female hastata, male clanga and male rapax overlap in several measures of size.

there....that clears that up then

 

[Jane Turner]

ok here's some relevant (I hope) from a brief e-mail discussion with expert Steve Parry re a possible article for an OBC Pub. Hope Steve doesn't mind....

there....that clears that up then

Wow...thanks Tim....clear...well no....not entirely

Any chance of asking Steve to pass a casual eye over this bird. The gape line does look big on the photo. but then again I've nothing to compare it with!

 

[Edward woodwood]

so you've digested that....

now cop this also via Steve Parry.

another difference between clanga and hastata - clanga usually shows a 'spiky' nuchal crest (particularly in juv plumage) when perched or at rest. Hastata does not seem to have one or much of one.

There is also a slight possibility of hybrids between
hastata and clanga, perhaps even clanga and vindhiana

The ID literature on all six of these eagles is very confused or
contradictory and they are always getting mixed up by even experienced
observers in the field

now u definitely know....

 

[Jane Turner]

I digested in as much as it blinking hard and all the literature is contradictory!

The one thing Sumit has in his favour is that this is a superb photo.... hopefully someone with loads of experience of these beasts can nail it.

What do you think by the way Tim... just a GSE or is there a chance is Indian SE?

 

[Edward woodwood]

I will send it to Steve.....he may be in the field though.

 

[Jane Turner]

I will send it to Steve.....he may be in the field though.

Looking at the OBC sdatabase, it was clear that there are only two individuals of hastata, one of which is a ringer for the mystery eagle

 

[Edward woodwood]

As for the ID I really couldn't say. As in Steve comments everyone gets these messed up and the lit. is all confused too. It's a rare taxon so a photo would be a very important one indeed, and circumstantially you'd say not hastata but not based on anything concrete at all!

 

[Jane Turner]

For reference a Greater Spotted eagle with all its outer 7 primaries and wing in about the same position as the mystery bird. Here 4=5 is the wing point,as I assumed for the mystery bird. The 7th is long and emarginated (though not as long and emarginated as the 6/7th on the mystery bird if it hasn't dropped its 10th pp

Added Is it just me, or does this look longer winged in relation to head size than the mystery bird

 

[Edward woodwood]

behave yerself Spar!

and to you to Spar ......one half day at Skool and then I'm off a-drinking and a-birding for a fortnight.

hope the tree is securely up now.

 

[Edward woodwood]

oh fantastic!

great memories in a few years......when you've forgotten the cost!

 

[Sumit]

Hi Folks,
Thanks a ton to all of you for your participation and contribution.
Seems like I missed all the fun, the perils of travelling to remote places in the sub-continent where you are lucky if you can connect for a few minutes !!
What I have from Mike Prince, (who wrote the Delhibird article quoted above) is that he thinks it is a juvenile GSE having seen enough GSEs and some ISEs in India. I will get Mike's logic across tomorrow. I have also written to the foremost Indian expert on raptors and await his views.
I can also add that ISE's though rare are frequently sighted in the Kaziranga area and most of the ISE images at OBC were shot in Kaziranga. So range and abundance should not be an issue in the ID.

Til tomorrow with a little more on this bird and thanks again.

Sumit

 

[Sumit]

A little late, but I got good stuff from Mike and I quote:

(Quote)" ... All the field guides discuss separation of GSE from LSE and this is probably mostly irrelevant and certainly very misleading for us in India. In addition Bill Clark's original paper in Ibis only discusses separation of ISE from LSE as well. ISE is much more similar to GSE than it is to LSE. When I last emailed Bill Clark specifically regarding features for ISE/GSE separation rather than ISE/LSE he just replied with the quote "it's very difficult". Maybe some of the LSE features quoted are also applicable to ISE, but I don't believe anyone really knows! How obvious and long certain primaries are maybe of use, but is difficult with worn or moulting birds anyway.

The bird is very broad-winged and short-tailed. It also has dark-brown underwing-coverts, appearing maybe darker than the flight feathers, and a mottled underwing band. These are very typical of GSE (particularly juvenile) and not ISE. I think this bird is most likely an immature: very worn flight feathers with some contrast probably of different aged feathers." (unquote)

Cheers!
Sumit

 

[Jane Turner]

Thanks Sumit. Hopefully your pic is good enough to be of use if any further features emerge.... one thing though...I don't think it can be a juvenile... it in a resumed, suspended moult. The first one post juvenile is complete..

 

[Sumit]

Thanks a ton Jane for your interest, support and contribution. I agree that this is by no means a clinched ID. The weight of evidence seems to veer towards GSE but so little is known about ISE that we cannot eliminate that species with any certainity. As you rightly suggest, the image may have use as we continue to struggle with aquila identification.
Thanks to everyone who contributed with time and energy. I am indeed indebted.
Cheers!
Sumit

 

[Jane Turner]

I really enjoyed it thanks..

 

[Edward woodwood]

Hi folks

Steve Parry, having seen the pic is of the opinion it's probably a clanga but is not sure enough to say for def.

I will send it to Bill Clark who may be able to go a little further

 

[mikeprince]

Having been sent the pic direct by Jane I thought I'd share my reply with everyone else. Firstly a caveat: although I wrote the Delhibird article referenced above I have not (as Sumit said!) seen several ISEs in India. In fact I'm yet to convince myself 100% that I've seen one, mainly because I really can't find out how to identify them!

Anyway, back to this eagle. As Sumit mentioned I initially thought Greater Spotted Eagle based mainly on structure and general colouration. Having looked at it a bit harder I inconclusively agree with Jane that it is a "possible" Indian Spotted Eagle.

Unfortunately I don't know whether features such as the short 7th primary and double carpal crescent apply to Indian Spotted in the same way they do for Lesser Spotted. I agree P7 (or what I think is P7 from this immature in active moult) looks short, which would not be expected on GSE. However a breeding ISE in south India at the moment is apparently also showing a long P7 as do the ones (that are clear enough to tell) on www.delhibird.org/species/sp007511.htm. The double carpal crescents again are not a good GSE feature but I'm not sure about the validity of this on a relatively mottled immature bird. Also I note the barring on the flight feathers seems to extend indistinctly across the primaries and I think GSE should have unbarred primaries?

The underwing coverts do not seem especially pale to me, and are certainly within the range for older GSE.

Unfortunately the gape breadth seems to be the best feature for identifying ISE and although looking thick the angle of this photo does not allow this to be assessed accurately enough. I'm still not sure whether the length of the gape is a useful feature or not - the Ibis paper by Parry, Clark and Prakash says that it "extends beyond the eye" however Bill Clark said in an email to me that "it is only on nipanensis [sic, i.e. Steppe] that the gape extends to the back of the eye".

Easy really, isn't it?!

-- Mike --

 

[Jane Turner]

Thanks Mike. Hopefully when we do know what the features of ISE are this pic may be good enough to say it is...or it isn't one!

 

[Sumit]

Hi All,
Rishad Naroji feels that this is a Greater Spotted Eagle. Rishad is an recognized authority in India on matters relating to raptors.
Cheers!
Sumit