How many morphs do we know for Atlas Long-legged Buzzard?

How many morphs do we know for Atlas Long-legged Buzzard? – Andrea Corso

In all the available field guides, but also on major work such as Cramp & Simmons (1980) there are no mention neither illustrations of any other plumage of Atlas Long-legged Buzzard (Buteo rufinus cirtensis) but the pale one which is the best known and the  most widely photographed, corresponding to the pale plumage of nominate subspecies rufinus. Indeed, most of the European birders still know and could ID only this plumage, while some other recently started to realize that the variability is much higher, even higher than in nominate;  indeed, back only in the 2006 there were some reports in Spain (one at Cazalla, Tarifa on 23rd September 2006; one at Cadìz, 14th September, 2006) of some “odd” Buteo sp., identified as vulpinus by all birders while considered cirtensis  by myself (http://www.rarebirdspain.net/arbsi033.htm). Indeed, regularity since 1999 I started to study the matter, as I am very passionate about North African birds and zoology in general there. In the Rare Birds in Spain paper above mentioned, for the first time I reported about all the other plumages (including the at the time unknown in modern literature  “grey-brown birds”) that I observed on Atlas Long-legged Buzzard, with several details on the identification of this taxon. Since then, I got tens of photos, mostly from Spanish and Portuguese birders, asking for an opinion on the identity of several buzzards there observed time by time. I answered in details with all the characters, as long as I could, but was clear even to myself first that the problem was far more complicated, and that simply, many birds should have left unidentified or deserved a more in depth study. Therefore, I visited museums to handle all the skins and, more importantly, I visited North Africa and the Middle East since 1999 annually, 3 to 5 times per year. I have been looking at pairs at nest (20 in Tunisia, 10 in Morocco, 2 in Egypt) year by year, and I was carefully checking all the observed birds. My results will be published on an extensive article in due course in Dutch Birding where the fruits of this long study will be printed on paper, alongside with many photos and plates but here I whish to report at least about the morphs of that fascinating, least known Western Palearctic raptor. I hope you will like this short summary.

1.A typical rufous plumaged Atlas Long-Legged Buzzard. This is one of the first birds reported in Tarifa – Cadiz area, Spain and mis-identified by all birders as B.b.vulpinus, then correctly ID by myself as B r cirtensis. Note the very long and striking tarsus, the long gape-line, the dark carpal patch (though not as solidly and uniformly dark as on nominate rufinus). Photo © Stephen Daly

1. A typical rufous plumaged Atlas Long-Legged Buzzard. This is one of the first birds reported in Tarifa – Cadiz area, Spain and mis-identified by all birders as B.b.vulpinus, then correctly ID by myself as B r cirtensis. Note the very long and striking tarsus, the long gape-line, the dark carpal patch (though not as solidly and uniformly dark as on nominate rufinus). Photo © Stephen Daly

For a matter of easier description, we could include into three main plumages or “morphs” the appearance of adult birds but with many intergradations and gradual changing which constitute a spectrum of colour gradient : 1) a pale plumage that vary from a very pale, almost sandy-white (which is most common on desert areas) to a more patterned and contrasted plumage, the one typically shown in field guides and references and 2) a rufous plumage, which is a rich rusty-warm colour quite uniform coinciding with the fox-red plumage of vulpinus, found all along the distribution range, but less illustrated and described, grading into a 3) darker plumage (here described separately for a matter of relevance) which may be the darkest end of the pigmentation variability,  being grey-rusty brown, very much the same the grey-brown morph of vulpinus and often even extremely similar to many buteo (chiefly of the southern populations), more commonly distributed in the northernmost part of the range and that is the least known plumage of all. The existence of a third type, a dark morph, is also discussed though is not yet proven behind any doubt. Juvenile mostly show two main plumage with several intermediate birds: a most common pale plumage with more or less extensive dark patterning (like the streaking of underbody) and a much darker, browner, more patterned plumage which could be less broadly dark marked or with dark markings wider and more extensive. The presence of a pale U over the belly or the breast as on Buteo buteo ssp. vary a lot, and is more commonly found on darker birds, while, contrariwise to the rufous morph in the nominate taxon where it is very rarely shown, regularly rufous plumaged cirtensis may show this marking though often is indeed lacking.

1)     PALE, BEST KNOWN PLUMAGE

Adult – In all the field guides today available, only the plumage closest to the most common one in nominate is described and illustrated, ie the pale morph which is always, also in the nominate, the easiest to identify and the most typical. Adult birds are rather easy to identify and to distinguish from buteo and also from vulpinus, despite the small size and the more compact looking enhance the similarities between the latter and cirtensis. The plumage is rather richly coloured, with a tendency to orange-buff, ochre or orange-reddish colour, as in nominate rufinus, with typically breast and  neck to head paler than the remaining underparts, which are always darker, with in fact darker brownish-rusty trousers and flanks. In flight, the dark areas underneath stand out as two body side dark patch in an otherwise pale bird. Compared to nominate however, flanks and trousers have usually a more reddish or rusty-orangish hue, lacking the blackish hue of nominate,  and often the lowest thigh feathers are paler and least marked. In many birds, the trousers (thighs) and flanks are only marginally darker and slightly rustier than the rest of the body, or even concolours with the body. However, contra for ex. Svensson et al (2009) and many other references, the thighs could be also as dark as in nominate, sometimes also in birds belonging to this “morph”.  The belly and lower vent are usually paler than in nominate, and in this plumage usually least patterned. Therefore, the contrast between higher underparts and lower underparts, shown as a be-colour impression is more obvious and striking in the nominate race while it appear most of the time more “patchy” dark and pale in cirtensis. Indeed also, the head and neck stand out less dramatically than in nominate,  the forehead and the crown being in most birds darkish, forming often a darker “hat”, and the neck is more streaked by pencil-like dark streaks. Also, more often than in nominate, there is a contrasting paler U over lower breast, similar to the one shown by buteo and vulpinus though usually less marked and less obvious. The carpal patch is almost black (though tinged rusty or brownish more often than in nominate) and is usually rather solid and extensive, however, note that more frequently than in nominate race the carpal patch could be reduced to a dark “comma” at wrist or a “double comma”. The tail is very bright and richly coloured, once fully and definitely in adult plumage, is cinnamon-orange or rusty-orange when fresh, fading once abraded (and sun-bleached) into a off white or creamy white. When typical, the tail, is to be considered immediately different from any vulpinus, even the most colourful fox-red-morph (Forsman, 1999; Clark, 1999; Shirihai & Forsman, 1991, Shirihai al. 1996; pers. obs.) being richer coloured, more orange and showing no dark barring. In palest birds the tail could be often creamy-buff even when fresh and not only when abraded and sun-bleached as in all rufous birds. Mostly younger adult usually show a various amount of dark barring (form 1 to 8 or 9 dark bars), which are often irregularly patterned and irregularly diffused among the different tail feathers and on inner and outer webs. FOR MORE IN DEPTH DISCUSSION ON TAIL BARRING SEE CORSO, IN PREP. Legs and cere yellow, sometimes bright yellow (mostly males) and in other birds tinged greenish (mostly in female when pair seen at nest). – White birds: some birds, mostly from the southern desert area of the breeding range, show an extensively very pale plumage that is so well defined that could even be differentiated in a paler type plumage or “morph”. They show an almost fully white-buffish underparts, sometimes, the thigh-feathers are slightly orange or cinnamon-creamy, other times there is only an hue of orangish tinge on flanks and thighs. Uderwing coverts are ocreous or buff, very pale and unmarked, with a very obvious and contrasting black carpal patch never observed like so in  buteo  and in vulpinus. The carpal patch in the palest birds is however sometimes missing and limited to a dark or darkish “comma” at wrist. Upperwing coverts are also often rather whitish, appearing the upperwing (chiefly if abraded) strongly two-coloured as on abraded juvenile Short-toed Eagle in 2nd calendar-year. Indeed, in the field, these birds are often very similar to a late 2CY Short-toed Eagle. Note: Of course, this plumage is the one which abrade and that chiefly sun-bleach sooner and more obviously, due to the fact that is mostly found in desert areas! The white impression is therefore even more striking for that reason.

2.A typical plumaged bird, this is the commonest plumage (or morph) encountered and the most commonly illustrated and described in modern filed guides. The head could be paler than in this bird, as usually in nominate, but most of the time is less strikingly paler indeed than in rufinus. The thighs are commonly bright rusty-rufous, lacking in many cases the blackish tinges shown by most nominate rufinus. However, this is more variable than reported in literature, and in many darker birds there is in fact a blackish tinges.

2. A typical plumaged bird, this is the commonest plumage (or morph) encountered and the most commonly illustrated and described in modern filed guides. The head could be paler than in this bird, as usually in nominate, but most of the time is less strikingly paler indeed than in rufinus. The thighs are commonly bright rusty-rufous, lacking in many cases the blackish tinges shown by most nominate rufinus. However, this is more variable than reported in literature, and in many darker birds there is in fact a blackish tinges. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

3.An adult male of the typical plumage but of these birds more typically encountered (but not exclusively) on desert areas which show a very clean, unmarked plumage where the white colour is predominant. Usually, the thigh-feathers are still rufous tinged, but in some extreme birds, chiefly once abraded and sun-bleached, the whole underparts could appear off white or creamy white.

3. An adult male of the typical plumage but of these birds more typically encountered (but not exclusively) on desert areas which show a very clean, unmarked plumage where the white colour is predominant. Usually, the thigh-feathers are still rufous tinged, but in some extreme birds, chiefly once abraded and sun-bleached, the whole underparts could appear off white or creamy white. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

4.Same bird (fig.3) from above, note that the tail when sun-bleached become almost white too. When is fresh the tail is orange-cinnamon or rusty-orange tinged reddish. However there is a great deal of variability in the tail colour and pattern.

4. Same bird (fig.3) from above, note that the tail when sun-bleached become almost white too. When is fresh the tail is orange-cinnamon or rusty-orange tinged reddish. However there is a great deal of variability in the tail colour and pattern.  Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

5.Same bird head profile. Note how pale and contrasting is the head, in that case just like in nominate rufinus. Note also the long powerful bill and the long gape-line.

5. Same bird head profile. Note how pale and contrasting is the head, in that case just like in nominate rufinus. Note also the long powerful bill and the long gape-line. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

6.Close view of the faded tail of the same bird. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

6. Close view of the faded tail of the same bird. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

Juvenile – Typical juvenile bird appear normally rather pale, with least marked underbody, chiefly an almost unmarked breast and higher belly with very narrow darker pencil streaks. The dark spotting/streaking its often more conspicuous to the side of the breast, while in most case the central area its least marked or clean. Lower vent and thigh feathers are usually more marked, more patterned and darker, as well are the flanks, those are in the higher part more frequently than in typical adults tinged blackish as in nominate or at least slaty-grey dark brown. The darker flanks and partially the thigh-feathers stand out strikingly in flight as sides dark patches over an otherwise pale bird. Normally the whole plumage its below a pale buffy – creamy white that soon bleach into off white, and a pale brownish above with a cold grey cast, mostly over wing and typically over the tail where there is extensive frosty icy off white or greyish-white, in wide pale areas. Conspicuous is a darker crown and forehead giving an “hat” impression and enhancing the pale supercilium, while the nape its pale, off white. These, combined to dark obvious moustachal mark and often, but less, a broad dark eye-stripe give to the bird a very Saker-like impression. Underparts marks usually shaft streaks, a barely barred pattern to some flank feathers, while adult shows extensively barred feathers. On underwing, greater and most median coverts unmarked white, lesser and marginal coverts show instead dark shaft marks. Carpal patch less striking than in adult being more peppered/patterned pale. Among typical juvenile as for adult there are some palest plumaged bird, that we may call the white-morph, that appear almost fully off white with barely some sparse darker drops (pale brownish or pale rufous-rusty) on lateral corner of the breast and vent. In this birds, the flanks still are darker and more marked, but much less than in typical plumages, and the thigh-feathers, noticeably the lowest trousers, are often also fully off unmarked white. When faded and sun bleached, from upper view these birds looks like a small abraded juvenile Short-toed Eagle, with contrastingly paler upperwing coverts and head. Structure typical of juvenile buzzards compared to adults, with narrower wings, more S shaped on lower profile, shorter and broader “fingers”, longer tail. Iris variably pale colored, from yellow to yellowish grey or dark sullied grey (sexually or individually related?), sometimes remaining greyish up to 2 years (pers. obs.). Bare parts bright yellow, just barely tinged bluish when into the nest and mostly the female (pers.obs. and contra several references).

7.A typical juvenile plumage, though often this is the plumage found mostly among birds from the drier and sandier desert areas, while many juvenile show the dark markings more broader and more extensive as in Fig. 7ii

7. A typical juvenile plumage, though often this is the plumage found mostly among birds from the drier and sandier desert areas, while many juvenile show the dark markings more broader and more extensive as in Fig. 7ii Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

7ii

7ii Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

2)    RUFOUS PLUMAGE

Adult –  Never illustrated in any modern field guide, is a second morph, the rusty-rufous or simply rufous. Birds with this plumage are more common to the north of the breeding range, but is sometimes found also to the south.  This plumage show a rather extensively warm rusty brown or reddish plumage, with duller or rustier flanks, thigh-feathers and middle belly, darker and more contrasting in most birds than undertail coverts, lower belly and breast which are paler and cleaner. Sometimes the thigh-feathers and the flanks are tinged dark sooty grey or blackish-brown. Usually, the undertail coverts are rather paler, being orange or pale creamy almost off white like the lower belly and the breast. These area may be uniform or barred/blotched with marks being deeper rusty or brownish. The breast its uniform in the real rufous or fox-red plumage, or with shaft streaks more reddish or darker rusty, but could be frequently streaked with blackish-brown or dark grey. In several birds it is noticeable a paler U over the breast, like the one in buteo  and vulpinus, more frequently that on the nominate subspecies, but often there is no hint of such a pale U pattern. The head its rather uniform with the lower parts but show a darker crown forming a dark “hat”, dark moustache, malar and gular stripes. Underwing coverts are usually rather uniform and reddish or rusty, with a variably extensive and marked black or blackish carpal patch, however always wider and more contrasting than in typical buteo  and typical vulpinus (but exception exist). Upperparts browner and darker, with extensive rusty or orange-reddish broad fringes when in fresh plumage. Tail as for pale plumages but usually more often and more extensively barred even when fully adult, or more rusty. In some birds the tail is dark sooty grey, tinged rusty and brownish, mostly at the central part along the shaft, always with a cold frosty tone lacking in buteo and vulpinus.

Juvenile –  As the juvenile of the pale plumage but more extensively dark marked, duller, more patterned, with darker underwing coverts, darker tail with wider barring, more patterned undertail coverts and thigh-feathers and flanks, darker head. Some show wider dark shaft streaking over breast, neck and belly approaching very much Common Buzzard of the nominate taxon, mostly the birds from the southern populations, being almost identical for ex. to juvenile buteo  from Southern Spain, Southern Italy, Sicily, and hardly distinguished from them (see under Identification – note especially tarsus length and strength, bill size, gape line, hovering attitude, calls).

8.A paler type of the rufous plumage. This is a very variable plumage-type or morph (though this term is possibly less appropriate given the high variability and intermediate birds) with birds like this and extreme one like a uniform dark, intense rusty-reddish. Thigh-feathers could be either like in this bird or much darker, sometimes even blackish or earth-brown tinged.

8. A paler type of the rufous plumage. This is a very variable plumage-type or morph (though this term is possibly less appropriate given the high variability and intermediate birds) with birds like this and extreme one like a uniform dark, intense rusty-reddish. Thigh-feathers could be either like in this bird or much darker, sometimes even blackish or earth-brown tinged. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

9.Same bird as fig. 8 from above; note the very broad rusty-orange fringing to the upperparts and the fresh cinnamon-orange tail.

9. Same bird as fig. 8 from above; note the very broad rusty-orange fringing to the upperparts and the fresh cinnamon-orange tail. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

10.Head profile of the same bird, rather pale; note however that in most birds of the real rufous plumage the head is uniform with the breast, being also rather intense and dark rufous tinged.

10. Head profile of the same bird, rather pale; note however that in most birds of the real rufous plumage the head is uniform with the breast, being also rather intense and dark rufous tinged. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

11. A typical rufous plumage, rather dark and uniform. This plumage is not shown in modern field guide and unknown to most birders. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

12.A typical rufous plumage, rather dark and uniform. This plumage is not shown in modern field guide and unknown to most birders

12. A typical rufous plumage, rather dark and uniform. This plumage is not shown in modern field guide and unknown to most birders. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

Another rufous bird. Note the blackish tinge to the flanks and upper thighs in this bird. Note that the tarsus are very long, and that there is a blackish carpal patch.

Another rufous bird. Note the blackish tinge to the flanks and upper thighs in this bird. Note that the tarsus are very long, and that there is a blackish carpal patch. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

3)    RUSTY-BROWN AND GREY-BROWN BIRDS

Adult – This is the least known plumage, never shown in literature. This plumage is found mostly on the northern part of the distribution range of cirtensis and may constitute the darkest end of the rufous-brown pigmentation of the colour range spectrum in the species.  Some birds show a brownish plumage rather uniform, quite similar, sometimes almost identical to same morph in buteo and vulpinus, usually the brown is warm and with a rusty hue, but few birds have a really grey-brown plumage. In some darkest examples, this plumage could be considered the equivalent of a dark morph, though not the chocolate-blackish morph found in nominate rufinus and in vulpinus.  In those birds, the dark extensive and marked carpal patch, the structure (as the long and robust tarsus and heavy bill), and the full set of characters are indispensable for a positive identification. NOTE: However, should be kept in mind and accepted that it is better to leave unidentified many – or most-  of the birds in these plumages if the tarsus length is not seen perfectly and the call not heard alongside other characters (reported in Corso, in prep.). For example, grey-brown juvenile is in most case impossible to tell apart unless not seen perched very close or in the hands obtaining biometrical measurements. NOTE 2: genetic study should be done to verify if the birds in such plumages have or not pure genes of cirtensis. Indeed, they may be hybrids or may be the result of a genetic introgression with Buteo buteo ssp. from Europe (as shown for other sister taxa like Pine Bunting and Yellowhammer for example). The recent extensively documented and well diffused cases of mixed pairs producing hybrid offspring of buteo  x cirtensis in several southern European countries such as Sicily (Pantelleria island, Sicilian Channel – Corso, 2009), Spain (Elrroiaga, 2010) and Portugal (L.Palma, pers. com.) demonstrate that this is possible, and al least in European grounds already happen, in some areas also regularly and quite extensively (since when ? only recently?). In fact, should be stressed that many birds observed also in Northern Africa are impossible to be identified to a specific level at least on phenotype appearance only. It should be taken in mind, before DNA results are widely done and available to finally clarify this conundrum, that in museums there are skins of grey-brown plumaged Atlas Long-legged Buzzard, collect in the breeding grounds and during breeding season in the ‘800 and which I re-confirmed as showing the characters of cirtensis by their morphometric measurements (such tarsus length, bill height, wing-chord, tail length); this would means that if these are hybrids with Buteo buteo ssp. or the fruit of a genetic introgression, then the phenomenon occur since some hundreds years. Genetically, this is surely possible, as the genetic differences and distances are very low, with all the European Buteo sp. so close each other that some authors proposed to lump them into a superspecies (Riesing, et al. 2003; Kruchenhauser, et al. 2004). These authors report that “ In the genetic analysis, almost no sequence variability was found among taxa comprising the buteo–vulpinus complex as well as Buteo rufinus and Buteo oreophilus , suggesting gene flow and/or incomplete lineage sorting.”. This could imply that Atlas Long-legged Buzzard is either  a “younger” taxon than the nominate ssp., or that is among the Western Palearctic taxa of Buteo sp. the one which show more regularly and visibly characters derived from the ancestor parents.

14.This adult male from Morocco (12/1898) could be included into the grey-(rusty)brown plumage, with the predominantly brownish colour, well marked and extensively barred, white undertail coverts, etc. Birds in such plumage are practically identical to the same morph vulpinus and southern buteo, and often best left not ID. Only tarsus measurements, moult pattern, behavior (like the hovering style), close by comparison of the jizz, call etc could clinch the ID. DNA would be ideal to verify if any genetic flow / introgression has occurred within cirtensis, showing up with this plumage.

14. This adult male from Morocco (12/1898) could be included into the grey-(rusty)brown plumage, with the predominantly brownish colour, well marked and extensively barred, white undertail coverts, etc. Birds in such plumage are practically identical to the same morph vulpinus and southern buteo, and often best left not ID. Only tarsus measurements, moult pattern, behavior (like the hovering style), close by comparison of the jizz, call etc could clinch the ID. DNA would be ideal to verify if any genetic flow / introgression has occurred within cirtensis, showing up with this plumage. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

15.Same bird from above, not that the rusty orange fringes are extremely limited (scapulars, shoulders, some wing-coverts and neck sides) in favour of a grey-brown colour. Note the tail pattern and colour, very vulpinus-like.

15. Same bird from above, not that the rusty orange fringes are extremely limited (scapulars, shoulders, some wing-coverts and neck sides) in favour of a grey-brown colour. Note the tail pattern and colour, very vulpinus-like. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

Juvenile –  even darker than the rufous juvenile, with very extensive dark patterning like wide shaft streaks and spots or extensive blotching with some feathers area wholly earth- brown. Most of the juvenile of this browner plumage are identical or nearly so to many Buteo buteo ssp. and only different in few characters hardly seen in the field, such for ex. the tarsus length (but see Corso, in prep.).

16 A pretty dark juvenile, often found as offspring of grey-brown parents and almost only on the northern part of the distribution range. Juvenile of this plumage show the dark marking very extensive, and in the field are virtually identical or identical to many vulpinus and buteo.

16. A pretty dark juvenile, often found as offspring of grey-brown parents and almost only on the northern part of the distribution range. Juvenile of this plumage show the dark marking very extensive, and in the field are virtually identical or identical to many vulpinus and buteo. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

16ii. Head on profile of a dark juvenile.

16ii. Head on profile of a dark juvenile. Photo © Natural History Museum, Tring (courtesy of NHM , Tring Staff).

–         Dark morph

All authors report that cirtensis lack the dark morph (Shirihai et al., 1996, Svensonn et al. 2010, Cramp, 1980,  Ferguson-Lees & Christie, 2001, Clark, 1999). Corso  (2002) discussed the possible existence of an extremely rare dark morph, based on a video on Tunisian raptors by J-M. & M. Terrasse from 1987 where an Atlas Long-legged Buzzard going to a nest, filmed in Northern Tunisia, seems to be fully dark chocolate or warm brownish dark. Being a dark morph in cirtensis considered lacking by all the previous authors, caution is required. However, several Buteo sp. observed on the breeding range of cirtensis by several observes were in a dark  chocolate brown plumage (see more details in Corso, in prep.). I do not yet consider sure the existence of a dark morph in cirtensis, though extremely rare, before obtaining good photos or a skin. However, in light of the reported observations, I think it is better to warn any visiting birders of the breeding range of cirtensis to be aware and to search for this plumage.

Main literature

(other sources not reported – see Corso, in prep.)

Corso, A. 2006. Some notes on the identification of North-West African Long-legged Buzzard Buteo rufinus cirtensishttp://www.rarebirdspain.net/arbsi033.htm

Corso, A. in prep. Identification of Atlas Long-legged Buzzard. Dutch Birding

Kruckenhauser, L., Haring, E., Pinsker, W., Riesing, M. J., Winkler, H., Wink, M. & Gamauf, A. (2004). Genetic vs. morphological differentiation of Old World buzzards (genus Buteo, Accipitridae). — Zoologica Scripta, 33, 197–211.

Riesing, M. J., Kruckenhauser, L., Gamauf, A. & Haring, E. (2003).Molecular phylogeny of the genus Buteo based on mitochondrial marker sequences. Molecular Phylogeny and Evolution, 27, 328–342.

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One Response to How many morphs do we know for Atlas Long-legged Buzzard?

  1. Laurie Allan says:

    Fascinating and very informative, it is obviously very difficult to illustrate the range in a field guide after all they are only a ‘guide’. That is why articles such as yours and the other contributors on Martins site are invaluable. I have just returned from a couple of weeks late birding in Maroc, enjoyable as usual, only one perched LLB seen, pale-ish upperchest but will look closer in future –

    ATB and thanks for an enlightening post –

    Laurie –

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