Bird Identification

Telling young Honey-buzzards from Common Buzzards

Telling young Honey-buzzards from Common Buzzards is an everyday id. challenge along the major flyways at this time of year (mid-Sep). Although the adult Honeys have mostly already gone, the juveniles are now peaking, in some places joined by big numbers of Common and/or Steppe Buzzards.

Both species are extremely variable if you look at the plumage as a whole, and this variation can be bewildering to many of us, but if you just focus on the underwing, the whole thing becomes easier.

I have chosen three underwings to demonstrate the difference between a juv Common Buzzard and in this case two different juv Honey-buzzards. Have a look at the captions, and you will find it easy to tell them apart next time you see one.

The underwing of a juv Common Buzzard. Looking at the flight-feathers first, note how uniform the ground colour and the barring appears, the trailing edge is clearly darker and the barring is rather fine and dense. Looking at the coverts, note the dark triangle along the leading edge, a feature shown by all Common Buzzards except for the palest ones. Note also, that the median coverts form a pale band to the underwing, another diagnostic Common Buzzard feature.

The underwing of a juv Common Buzzard. Looking at the flight-feathers first, note how uniform the ground colour and the barring appears, the trailing edge is clearly darker and the barring is rather fine and dense. Looking at the coverts, note the dark triangle along the leading edge, a feature shown by all Common Buzzards except for the palest ones. Note also, that the median coverts form a pale band to the underwing, another diagnostic Common Buzzard feature.

The underwing of a dark morph juvenile Honey-buzzard. This is the most common colour form in juveniles and 4 out of 5 juveniles would be of this form. Compare with the Common Buzz above and note that secondaries are notably dark, often clearly darker than the primaries and that the barring is sparse and heavy. Looking at the coverts, note the uniformity, which in Common Buzz is only found in black morph Steppe Buzzards (not in Europe!) and that it is the greater, not the median coverts, which appear lighter.

The underwing of a dark morph juvenile Honey-buzzard. This is the most common colour form in juveniles and 4 out of 5 juveniles would be of this form. Compare with the Common Buzz above and note that secondaries are notably dark, often clearly darker than the primaries and that the barring is sparse and heavy. Looking at the coverts, note the uniformity, which in Common Buzz is only found in black morph Steppe Buzzards (not in Europe!) and that it is the greater, not the median coverts, which appear lighter.

The underwing of another, slightly more marked juvenile Honey-buzzard. Although the flight-feathers are lighter in this bird, note the sparse and heavy barring and the dusky secondaries.

The underwing of another, slightly more marked juvenile Honey-buzzard. Although the flight-feathers are lighter in this bird, note the sparse and heavy barring and the dusky secondaries.

Solution to Eagle Quiz #2

What is the eagle in quiz #2?

To be honest, I don’t know, but this needs a bit of explaining.

It is obvious that it is one of the “brown Aquilas”, Lesser Spotted , Greater Spotted or Steppe Eagle. The plumages of all these species vary a lot depending on age, but there is also a considerable variation within each age-class. The single most reliable id. character in these three species is the barring of the remiges, the large flight-feathers of the wing. The barring of the remiges does not vary as much as the body plumage, and all three species have their own typical barring. All this has been explained in the relevant identification literature.

Based on plumage characters, including also the wing barring, Steppe Eagle can easily be excluded. In Steppe the barring is coarse, with fewer and more sparsely spaced bars to each feather compared to the two Spotted Eagles.

Adult Steppe Eagle. Note the sparse barring to secondaries. Eilat, Israel, Nov 6th, 2009

Adult Steppe Eagle. Note the sparse barring to secondaries. Eilat, Israel, Nov 6th, 2009

We are thus left with the two Spotteds. In juvenile and the following immature plumage the barring is different in these two species, but with increasing age the barring gets more and more similar. In definite adult plumage both species show uniformly dark remiges with no barring at all. Based on the type of barring of the remiges, and the moulting sequence, this bird can be aged as a third plumage individual (3rd cal yr autumn). This means, that it still shows the diagnostic barring of the remiges, particularly in the secondaries and the inner primaries. In Greater Spotted Eagle (GSE) this barring is in juveniles fine and sparse, with dark bars much narrower than the pale interspaces, and the barring is confined to median parts of the feather, often with unmarked basal and distal parts of eg. secondaries. The same pattern will prevail also in the next generation of moulted feathers. In Lesser Spotted (LSE) the barring is denser with broader dark bars and the paler interspaces are as narrow as the dark bars. Further, each secondary is barred like this from base to tip, making the overall impression darker and very different from a juv GSE.

Greater Spotted Eagle 2nd cal yr autumn, Nov 2004, Oman. Note the finely barred remiges and how the barring is confined to the median section of the feather, leaving basal and distal parts plain.

Greater Spotted Eagle 2nd cal yr autumn, Nov 2004, Oman. Note the finely barred remiges and how the barring is confined to the median section of the feather, leaving basal and distal parts plain.

Lesser Spotted Eagle, 2nd cal yr autumn, Israel, Oct 2009. Note the dense and uniform barring of remiges, covering the entire length of the feather.

Lesser Spotted Eagle, 2nd cal yr autumn, Israel, Oct 2009. Note the dense and uniform barring of remiges, covering the entire length of the feather.

However, our quiz bird, clearly a Spotted, shows a feather pattern intermediate between GSE and LSE. This is clear when we are looking at the three remaining juvenile secondaries (S4, S8 and S10 counting inward towards the body). The barring is too dense and the bars too broad for a typical GSE, but at the same time it is too sparse for LSE, and the bars also get finer towards base and tip, suggesting a GSE pattern. If we forget the barring for a while and look at the rest of the plumage, we can see a most distinct inner carpal crescent, looking just like the carpal area of LSEs of this age. Many GSEs have a second carpal crescent in juvenile plumage, but by this age it should be lost. The general milk-chocolate brown colour of the plumage is more in line with LSE, while a GSE of this age should be darker and colder brown. The iris colour of a LSE of this age should already be very pale (at least in most birds), while a GSE should have a dark iris. Again, this bird shows an iris colour intermediate between the two species. The proportions of head and bill look to me perfect for a GSE, although this is a very subjective character.

As you already might have guessed, my conclusion is, that this could be a hybrid between GSE and LSE, and I actually also believe it is one, but, of course, this is impossible to prove. It is not necessarily a F1 hybrid, but it could be a back-cross between a hybrid and a LSE. Hybrids between these species are fairly common and have also been well documented in the eagle populations of the Baltic States and Poland. Since the eagles are long-lived and the hybrids are fertile, various types of hybrids and their back-crosses can be expected to turn up wherever the two species occur, including on passage or as vagrants. Next time you are identifying a Spotted Eagle you should also consider the possibility of a hybrid. They appear to be far more common than the average birder could ever have dreamt of.

Eagle Quiz  #2

I photographed this eagle in N Israel on Oct 5th this year. Give it a thorough look, use all your knowledge and all your books, and see if you can identify it.  With all the relevant details visible it should be a piece of cake, but is it?  Comments will follow in the near future. Stay tuned.

Can you identify this this eagle? In the field it could not have passed any closer, and with all the details visible it should be a piece of cake. But is it?

Can you identify this this eagle? In the field it could not have passed any closer, and with all the details visible it should be a piece of cake. But is it?

Another tough harrier!

Went out today (Aug 30th, 2009) to my local patch (Kirkkonummi, Porkala, roughly 60N x 24 E) , for the first time in weeks, to check out the raptor migration. Small groups of adult Honey Buzzards were heading south and some migrant Kestrels were hovering over the stubble fields, but apart from those very little was happening.

I soon arrived at a harvested field, which has been good for raptors in the past. Some 200 metres out I noticed a harrier, busy harassing a group of crows feeding among the stubble. The first looks through my binoculars sent shivers down the spine: It showed a strikingly distinct and complete pale collar around the neck, unstreaked buffish underbody and underwing coverts (lesser and median), slim body and rather narrow wings, and the flight was fast and the bird remarkably agile! I walked closer across the field, reaching down to 100-150m from the bird, in order to get some documentary pictures, and through the viewfinder of the camera I could see all the features of a classic juvenile Pallid, a female judged by the dark iris. Two juv Pallids had been seen in the general area, on and off over the past week, so I had absolutely no problems in convincing myself, that I was watching one of them.  Unfortunately, the bird soon lost its interest for the crows and drifted off, disappearing behind some trees. It was never seen again, despite the efforts of more birders arriving at the scene.

The shock came to me when I got home and started to process the images. The bird did indeed show all the forementioned features, BUT it also showed a deep emargination to the outer vane of p6 (the fifth “finger” counting inwards)! This is something a real Pallid never shows, but rather something typical of a Hen Harrier!  Scrutinizing the bird in detail, it also proved to show an underwing barring more similar to a juv Hen than to a typical Pallid,  and the pale area around the eye was too wide for a normal Pallid, again more like in a juv Hen. But then the wing-formula was not as rounded as that of a female Hen, the wings appeared narrow and the body was slim and so was the head. During all the time I watched it, mostly through the camera, it never gave the impression of a female Hen Harrier. The flight was fast and direct, and when harassing the crows it was  remarkably agile.

So what is this bird? Is it just a Hen, with plain underbody and plain underwing coverts? Do Hen Harriers like this even exist in the first place? Or is it some kind of a hybrid between Hen and Pallid?  Pallid Harriers have become increasingly common in Finland over the past years, and several are known to summer in areas where Hen Harriers breed commonly.  To be honest, I don’t know what this bird is, but without the pictures I surely would have submitted it as a good Pallid, now of course I won’t!

Anyway, the pictures remain for anyone to assess, and whatever this bird is, it definitely deserves some attention. Can birds looking like Pallids any longer be identified as Pallids?  Have a thorough look for yourself and see what YOU think about this bird. Would you have  given it a second thought in a normal fly-by situation?

Note unstreaked, Pallid-like body and underwing coverts and distinct and complete neck-collar. The wing-formula, underwing barring and amount of white around the eye are, however, reminiscent of Hen Harrier.

Note unstreaked, Pallid-like body and underwing coverts and distinct and complete neck-collar. The wing-formula, underwing barring and amount of white around the eye are, however, reminiscent of Hen Harrier.

Upperparts, showing emarginated p6. Note head-markings

Upperparts, showing emarginated p6. Note head-markings

Note head-markings, underwing markings, the plain body and the long 5th finger

Note head-markings, underwing markings, the plain body and the long and emarginated 5th finger

It is a Tawny Eagle!

It has taken me some time to revisit this case, but now is the time. As you can read above, the bird is an adult Tawny Eagle, an extremely variable species occurring all over Sub-Saharan Africa (and in India). It is poorly treated in current fieldguides and handbooks, although its plumages are many and the plumage variation is much wider than generally appreciated.  The Tawny is a breeding species in Ethiopia, while the Lesser Spotted occurs on passage and the Greater either on passage or as a scarce wintering bird around the Rift Valley lakes and wetlands.  This picture was taken in early May this year, which is a bit late for the spotteds, but probably still a possible date. Thanks again to John Graham from South Africa, for sharing this bird with us!

This particular Tawny looks rather similar to both Lesser and Greater Spotted Eagle, and is a tricky bird to tell. Some Tawnies, like this one,  are streaked below like immature spotted eagles, and this fact is usually overlooked in the literature. Therefore, this is not a well-known plumage. The active moult in the wing (at p4)  tells it is an older bird, not a first winter, which is important to note.

The characters worth noticing are the uniformly colored remiges, lacking any barring (often the remiges are diffusely barred), the lack of distinct pale crescents at the carpal, the shortish and stocky-looking legs and the general proportions, with a comparatively slightly longer tail than in the spotteds and with less rectangular wings.  Any older Greater Spotted would normally show a striking, white crescent at the base of the outer primaries and birds with streaked bellies (=immatures and sub-adults) normally also show pale undertail coverts and barred remiges and the underwing coverts would be clearly darker than the remiges.  Any older Lesser Spots normally show two pale crescents around the carpal (an additional pale crescent at the base of the greater carpal coverts), while the remiges and body show the same characters as mentioned for Greater. The Lesser Spotted also shows a warmer chocolate-brown  colour to body and underwing coverts, but the colour of a Greater could be very similar to the bird in the pictures. If spotted eagles show pale streaking to the underbody, they  normally also show pale spots to the underwing coverts, which this bird is lacking.

In conclusion, the bird can be identified as a Tawny based on the combination of  barely noticeable, diffuse pale carpal patch, unmarked remiges and tail-feathers, stocky legs and by the fact, that the streaking is confined to lower breast only, while the undertail and underwing coverts are darkish.

I have seen and photographed a bird very similar to this in 1998, as the other member in a breeding pair in Wondo Genet, C Ethiopia, only some 15 kms from where this bird was seen, in Sheshemannee. That particular bird from 1998 was featured with a photograph in a trip report as a Greater Spotted, so these birds have indeed been misidentified before!

For comparison, below, adult Lesser Spotted and older immature Greater Spotted Eagles.

Adult Lesser Spotted Eagle, Israel, Sep 2008. Note barred remiges, warm brown underwing coverts and double-crescent at carpal. This bird has already lost its pale undertail coverts of the preceding immature plumages , but still retains pale markings to its greater underwing coverts.

Adult Lesser Spotted Eagle, Israel, Sep 2008. Note barred remiges, warm brown underwing coverts and double-crescent at carpal. This bird has already lost its pale undertail coverts of the preceding immature plumages , but still retains pale markings to its greater underwing coverts.

Third-winter Greater Spotted Eagle from Oman, Nov 2004. Note barred remiges, contrastingly dark underwing coverts and very bright carpal patch on this bird and compare with the quiz bird. Note also structure, with very broad and rectangular wings and shortish tail.

Third-winter Greater Spotted Eagle from Oman, Nov 2004. Note barred remiges, contrastingly dark underwing coverts and very bright carpal patch on this bird and compare with the quiz bird. Note also structure, with very broad and rectangular wings and shortish tail.

Which species of eagle?

Now you can test your id skills on this brown Aquila-eagle photographed in Ethiopia earlier this year by John Graham from South Africa.  The correct answer will be given here after you’ve had the chance to munch it for a while.

Aquila sp1

Aquila sp.

-

Tricky harrier

I was just sent some pictures of an interesting harrier taken by my friend Matti Pajunen.  This 2nd calendar year female harrier was photographed in Varanger, northernmost Norway on May21st. In the field Matti was first struck by the very prominent head-markings, which pointed towards Pallid Harrier. Also the practically unstreaked underparts, including the underwing coverts pointed to that species, but somehow the bird’s appearance and flight did not feel right for Pallid, which Matti is familiar with from before.

The wing-formula is one of the more important features when separating Hen and Pallid Harriers. This bird does not show a typical Pallid wing-tip, but nor is it the wing-formula  of a Hen: the fifth primary, counting inwards, is not clearly fingered as in Hen, but in length and shape something halfway between the two species. All in all, the wing has more the shape of Hen Harrier, being rather broad and rounded, whereas Pallids normally show a narrower and more pointed hand. However, some female Pallids may look rather stocky in appearance, so this is by no means diagnostic. The underwing markings are in favour of Hen, with distinctly barred primaries and secondaries, with the secondary bars continuing across the primaries (normally not the case in Pallid), but again, some young Pallids may show similarly barred secondaries and therefore look similar.

circus-matti-pajunenn210509skallelv-3w

circus-matti-pajunen-210509skallelv-2w

circus-matti-pajunen-210509skallelv-4wSo what is this bird? It is probably not a Hen Harrier, since too many things speak against it. Could it just be a Pallid Harrier, with less typical underwing barring? It could of course also be a bird with some hybrid background, since hybridisation between the two species is known to occur.  In 2005 a mixed pair raised young in Finland, and since then a few birds with mixed characters have been seen.  Unfortunately, the photographic conditions were rather poor (overcast and late evening) during the observation and especially the flight pictures do not show all the necessary details of the wing-tip that one would hope for. Anyway, an interesting record and an excellent reminder, that bird identification can be difficult even when you have relatively good photographs at hand.


Dick Forsman

is a Finnish ornithologist, author, artist and travel guide. Dick's deep interest in birds, raptors in particular, started during his early childhood and ever since he has built his life around this passion.

Blog categories