Author Archives: linosabirding

Taxonomical notes : Lesser Kestrel is really monotypic?

With these “taxonomical notes” I want to launch a series of notes and thoughts about some problem related to the taxonomy of Western Palearctic birds, addressing some conundrums which have not yet been studied in detail or did not get enough attention. Many of these notes are simply reported in order to stimulate further in depth studies by taxonomist and researchers, with some being instead only a brief view of my researches in due course and in progress. Indeed, for what concern this “first case” here reported, my study started back in Autumn 2003 and the whole problem will be presented on a specific paper in preparation.

Taxonomical notes : Lesser Kestrel is really monotypic?

By Andrea Corso

During autumn 2003, I was at Chockpak Ringing Station, Kazakhstan, alongside with three  Dutch birders and friend of mine (Arend Wassink, Justin J Jansen and Wim Nap), studying raptors and the other birds there, with the guiding of Professor Andrei Gavrilov. We visited as well many other sites of Eastern Kazakhstan. The trip was very interesting and fruitful for many aspects and the country was confirmed to be one of my favorite destination. Among the several remarkable observations, I was greatly intrigued by the pattern of the upperwing in most of the adult male Lesser Kestrel ringed and observed in the field. During the firsts observation days in Kazakhstan I was telling my fellow observers some tips about field characters of Lesser Kestrel. While talking about the upperwing grey panel in adult male I emphasized how this character is very often not visible under field condition and usually only at very close view, good light or in perched birds. Looking at the males flying around then, I was readily contradicted, as in all the males around, the grey on the upperwing was not only well visible, even at distance, but also very conspicuous and dark looking. This fact intrigued me very much so I started to check and study in details every male observed in the following days and eventually also all the birds caught to be ringed. It resulted therefore as almost 100% of the males observed shown more grey then I was used to see in European birds; this was confirmed by the many males caught during our stay at the ringing station. For what concern European birds, Corso (2000, 2001) report that to a certain degree, the upperwing grey panel could show a range of variability, among several other characters. However, not any of the European bird personally observed (some 20.000 adult males in total) ever shown an upperwing pattern that may look identical to the birds I observed in Kazakhstan. Rarely, birds within European population (chiefly from the eastern part of the range) may show a more extensive grey wing-panel, with all the GC (greater coverts) sooty-grey and in rare occasion some median coverts (MC) and tertials too (Corso, 2000, Corso, 2001; pers.obs.).  However, I never observed any European bird with almost the whole upperwing coverts dark led-grey all the way to scapulars and tertials as in some Kazakhstan birds.  None of the main references on European raptors either illustrate or describe birds like these (Cramp & Simmons, 1980; Snow & Perrins, 1998; Forsman, 1999; Clark, 1999; Ferguson-Lees & Christie, 2001). None of them even mention that the grey area (panel) appear to be greater in Eastern populations then in the Western populations. Only in Ferguson-Lees & Christie (2001) it is depicted a bird with more grey then usual but not as much as noticed in this study. In Forsman (1999), the only picture showing a male with much grey on upperwing has been taken in fact in Kazakhstan. I was therefore very excited as I thought to have found a yet un-described subspecies of the believed monotypic Lesser Kestrel. However, once back home, I started to search references on the taxonomy of this falcon and found that back in ‘800 a “variety” or race has been already described by Swinhoe.

Introduction

Nowadays, Lesser Kestrel Falco naumanni (Fleischer, 1818) is considered monotypic, with no subspecies recognized (Cramp & Simmons, 1980; Snow & Perrins, 1998; Forsman, 1999; Clark, 1999; Ferguson-Lees & Christie, 2001; Corso, 2000, 2001). However, Swinhoe described in 1870 a new race or “variety” (according to his given name) of Lesser Kestrel from Pekin, China which he named Falco cenchris var. pekinensis (Swinhoe, 1870). He described the holotype bird, collected on 18th October 1868, as following : “Large numbers of Kestrels were flying and hovering about. Their movement struck me as peculiar; and on shooting a male we found the species to be a race of Falco cenchris, Naumann. We procured on this occasion an adult male, and in the Western Hills a young male. They agree in size and form with Falco cencrhis of Europe; but the adult male has all the wing-coverts grey right up to the scapulars, most of them narrowly edged with rufous. The adult has the inner or short primaries broadly bordered at their tips with whitish, rufous in the immature, and wanting in the European bird. Both adult and immature have the white on the under quills 3 ¼ inches short of their tips; in the European bird it advances one inch nearer the tips. I will note this Eastern race as var. pekinensis. It will probably be the bird that winters in India.” (Swinhoe, 1870). Later on, Swinhoe (1871) on his “Revised Catalogue of the Birds of China” so reports “Breeds on the western hills of Pekin, and assembles in large numbers in September. Mr. Hodgson’s drawing of the Nepal bird (in the British Museum) shows that it is this race of Tichornis cenchris that resorts to India. The adult male has all the wing-coverts grey right up to the scapulars ; the inner or short primaries are broadly bordered at their tips with whitish, rufous in the immature ; the white on the under quills is 3^inches short of their tips. Subsequently, Jerdon (1871) report this taxon for the Birds of India. It is also mentioned later by Sharpe (1874) in his “Catalogue of the Accipiters, or Diurnal Birds of Prey, in the collection of the British Museum” and so described: “Very similar to C.naumanni, but darker and more vinous red above; underneath also darker-coloured and unspotted when adult. The principal distinction is the wing-coverts, which are almost entirely blue-grey, only the very innermost being slightly washed with rufous. Total length 12 inches, culmen 0-8, wing9-6, tail 5-8, tarsus 1-45. Hab. N: China; Himalayas.” Hodgson (1844, 1845a,b, 1855) mention too the race pekinensis. Hartert (1913) and Hartert & Steinbacher (1933) mention this race as well giving again a description fitting with the original one by Swinhoe and considering valid this taxon (though with some overlapping characters sometimes with the nominate naumanni and reporting some clines). Warren (1966) report :  “Syntype, Adult male. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe. Seebohm Collection. Proc. zool. Soc. Lond., 1870 : 442. Also Warren & Harrison (1971, 1973) reported again pekinensis.

More recently, authors has variously faced with the Chinese population from simply ignoring it, to mentioning and describing it as Falco naumanni pekinensis with the given English name of Eastern Lesser Kestrel or synonymizing it with naumanni (lumping together the two taxa): so, for ex. Brown & Amadon (1968) and Brown, et al. (1983) mention among the African raptors also Falco naumanni pekinensis reporting that this race is distributed from Turkestan to northern China, and in Africa it is observed outside the breeding season in Eastern Africa with “Most of the Lesser Kestrels passing through Somaliland appear to belong to this race”. These authors describe pekinensis as so “Adult male differs from the preceding race (naumanni) in having the grey of the wings extending up to the scapulars; secondaries broadly tipped with whitish and a greater amount of blackish on the ends of the primaries. The female and young differ on the latter character only.” Of the same opinion are Etchécopar & Hüe (1967) which report “F.n.pekinensis Swinhoe (Généralment plus gris, sur les moyennes et petites couvertures alaires); Migratrice : Venant d’Asie, accidentelle en Ègypte”. For the Avifauna of China, Etchécopar & Hüe (1978) report again F.n.pekinensis while more recently, Tso-Hsin (1987, 1994) in his synopsis, synonymize pekinensis with naumanni which is reported to be monotypic.  Vaurie (1965) mention Falco cenchris var. pekinensis only as a synonym of Falco naumanni, monotypic. Lesser Kestrel in Asia (Pakistan, South Asia, India, China) is considered monotypic also by Ali & Ripley (1978), Ripley (1982), Inskipp, et al. (1996), Grimmett, et al. (1998) while in the recent Rasmussen & Anderton (2005) no mention at all is given about pekinensis.

Discussion

Was therefore with no clear idea that I went to Tring, the Natural History Museum (NHM) (alongside with my friend and MISC member Ottavio Janni) to check the syntypes of Swinhoe, but eventually what I found were birds clearly different from any Western Lesser Kestrel I knew before. All the specimens labeled as pekinensis preserved into the collections held at Tring and at Almaty Nature Museum of the Zoology Research Institute of the Academy of Science (IZA) show obvious differences to all the other skins of birds collected in the breeding grounds within the Western Palearctic, while some birds collected in the African and even more in the Indian wintering grounds appear indeed similar. I divided the skins into A) birds collected in China during breeding season; B) birds of unknown breeding ground origin, collected elsewhere in Asia; C) birds which are typical naumanni, collected mostly in the breeding grounds of Europe and N Africa; D) birds collected during migration or wintering grounds in Africa, the Middle East and Arabian Peninsula; E) birds collected in India, during migration or winter time.

As shown in the here reported photos, all the birds coming from China (A), most of them labeled originally as pekinensis, show according to the original description of the holotype (called syntype by Warren, 1966 – why?) the whole upperwing coverts grey with also the tertials grey or partially grey. Additionally, the grey tinge is not only reaching the lower scapulars in some birds, but is also of a darker led grey, more sooty (less pure and cold bluish-grey or cerulean-grey), then the birds from Europe (C); on the same way, also the grey on the head and tail is darker and more sooty. The mantle, as correctly reported by Sharpe (1874) is of a deeper and darker vinous rusty-red colour, and the underparts are darker and more satured as well. Birds from other Asian countries (B), such as Kazakhstan, have similarly patterned wing-coverts, though in some birds less extensive and with in most birds part of the lesser and the leading edge rusty tinged (mostly as a rusty “patch” on the inner “harm”), the grey colour of head, tail and coverts being in some not so dark led grey as the Chinese birds (but in some birds being similar) and the underparts appearing less saturated as the mantle less vinous in many birds (but similar in some); indeed, these birds appear intermediate and could be called “cline”. Birds collected in the Middle East, Arabian Peninsula (as in UAE) and Eastern Africa during migration period or winter time have typical plumage (as C) or appear intermediate (as B), but their origin is not known so they could simply be taken into account as “intermediate” birds of unknown origin, while some birds collected in India (E) indeed look like “pekinensis” (as A). On the web and in ornithological books, several birds from India, Arabian Peninsula and Eastern Africa show either an intermediate plumage like birds of the group (B) or a “pekinensis-type” like plumage. The birds from Turkestan, described by Zarudny (1912) as Cerchneis naumanni turkestanicus and reported to have paler plumage than pekinensis with less grey on upperwing but more than on European birds, could be included into the group (B) as intermediate birds of clinal population, while the taxon Cerchneis naumanni sarmaticus (Domaniewski, 1917) is of no taxonomic value at all.

NB: For a comparison study, only birds of the group (A) and (C) could be taken into account, while birds of the group (B) in the middle could only be taken into account as clines or intermediate birds, which are normally found in every subspecies.

From a first and preliminary analysis, it seems that birds of the species’ range show an increasing amount of grey to coverts and saturation in colors moving west to east, with some birds from the Spanish population showing almost no grey on coverts (only a tinges or a tip to the greater coverts), moving east the coverts showing an increasingly wider amount of coverts grey tinged,  almost gradually, as well a more saturated plumage. Therefore, it seems likely that there is a cline in both the extension of the grey on the coverts and the saturation of the pigmentation, with however the Chinese birds being constantly different from all the other Lesser Kestrels and with the differences strongest and most visible. This is only a brief overview of the results obtained and a simple and basic summary, for a better and more in depth treatment see Corso, et al. (in prep.). However, from the preliminary result, not only it seems that the pekinensis taxon is valid, as being readily identifiable and obviously different, but that a genetic study of the Chinese population is surely advisable and should be taken into account (could be that result would indicate something like Red-footed Falcon and Amur Falcon, in the past considered conspecific and often called Western and Eastern RFF ?).

In any case, whatever the validity of pekinensis would be confirmed or not, and accepted or rejected, still the differences in the plumage of the eastern populations should finally be acknowledged and taken into account, as up to date these have never been considered and illustrated in any field guide, handbook or reference dealing with Asian birds in last decades and always Lesser Kestrel has been only depicted with the same wing pattern, therefore with a limited amount of grey on the greater coverts, often hard to be seen in flying birds.

1.Falco naumanni “pekinensis” – adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe (A.Corso - courtesy of NHM, Tring). Note the entirely led grey wing-coverts and tertials, well contrasting with the white leading edge feathers, the dark sooty led grey hood and the saturated colours of mantle (vinous red) and of the underparts. No illustration in any modern field guide is available of such a plumage, with no description or illustration reporting these characters.  Photo: © A.Corso - courtesy of NHM, Tring

1. Falco naumanni “pekinensis” – adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe (A.Corso – courtesy of NHM, Tring). Note the entirely led grey wing-coverts and tertials, well contrasting with the white leading edge feathers, the dark sooty led grey hood and the saturated colours of mantle (vinous red) and of the underparts. No illustration in any modern field guide is available of such a plumage, with no description or illustration reporting these characters. Photo: © A.Corso – courtesy of NHM, Tring

2.Falco naumanni “naumanni” – ad. ♂ from Spain. Note that in many European birds the grey on wing coverts is very limited and pretty hard to be seen in the field or even in the hands. Note that the plumage is paler, less intense and deep in both the grey of hood and wing-coverts and of the mantle and underparts. Photo: © A.Corso - courtesy of NHM, Tring

2. Falco naumanni “naumanni” – ad. ♂ from Spain. Note that in many European birds the grey on wing coverts is very limited and pretty hard to be seen in the field or even in the hands. Note that the plumage is paler, less intense and deep in both the grey of hood and wing-coverts and of the mantle and underparts. Photo: © A.Corso – courtesy of NHM, Tring

3.Falco naumanni “pekinensis” – adult ♂ .Note the deeply saturated underparts. Photo: © A.Corso - courtesy of NHM, Tring

3. Falco naumanni “pekinensis” – adult ♂ .Note the deeply saturated underparts. Photo: © A.Corso – courtesy of NHM, Tring

4.Falco naumanni “naumanni” – ad. ♂ from Cyprus, collected in March. Note the very pale underparts typically found in European birds (Western Lesser Kestrel) and compare with the eastern birds. Photo: © A.Corso - courtesy of NHM, Tring

4. Falco naumanni “naumanni” – ad. ♂ from Cyprus, collected in March. Note the very pale underparts typically found in European birds (Western Lesser Kestrel) and compare with the eastern birds. Photo: © A.Corso – courtesy of NHM, Tring

5.Upperparts of F.n.”pekinensis”  to show the very much saturated upperparts. Photo: © A.Corso - courtesy of NHM, Tring

5. Upperparts of F.n.”pekinensis” to show the very much saturated upperparts. Photo: © A.Corso – courtesy of NHM, Tring

6.1 “pekinensis” (leftmost bird) compared with 1 ad. ♂ from Afghanistan and 1 ad. ♂ from Spain, all from Spring, to show the decreasing intensity of the saturation of the grey and the mantle, which in European birds is less vinous-rusty and more terracotta with a pinkish hue.  Photo: © A.Corso - courtesy of NHM, Tring

6. 1 “pekinensis” (leftmost bird) compared with 1 ad. ♂ from Afghanistan and 1 ad. ♂ from Spain, all from Spring, to show the decreasing intensity of the saturation of the grey and the mantle, which in European birds is less vinous-rusty and more terracotta with a pinkish hue. Photo: © A.Corso – courtesy of NHM, Tring

7.Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso - courtesy of NHM, Tring

7. Same birds (above) from below. Photo: © A.Corso – courtesy of NHM, Tring

8.Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso - courtesy of NHM, Tring

8. Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso – courtesy of NHM, Tring

9.Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Mesopotamia labeled with the trinomial Falco n. naumanni. Photo: © A.Corso - courtesy of NHM, Tring

9. Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Mesopotamia labeled with the trinomial Falco n. naumanni. Photo: © A.Corso – courtesy of NHM, Tring

Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Palestine which is labeled with the trinomial nomenclature Falco naumanni naumanni , collected on 1923. Note the differences in saturation and colour tinge/hue of upperparts. Photo: © A.Corso - courtesy of NHM, Tring

10. Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Palestine which is labeled with the trinomial nomenclature Falco naumanni naumanni , collected on 1923. Note the differences in saturation and colour tinge/hue of upperparts. Photo: © A.Corso – courtesy of NHM, Tring

Close view of the head of same birds of fig.11 to show the grey hood paler in naumanni. Photo: © A.Corso - courtesy of NHM, Tring

11. Close view of the head of same birds of fig.10 to show the grey hood paler in naumanni. Photo: © A.Corso – courtesy of NHM, Tring

Again same birds in lateral view. Photo: © A.Corso - courtesy of NHM, Tring

12. Again same birds in lateral view. Photo: © A.Corso – courtesy of NHM, Tring

13. An adult ♂ Falco n. naumanni (centre) compared with two ad. ♂♂ “pekinensis” from China, to show how much paler pearl grey is the hood and less saturated, less rusty-vinous but more pinkish tinged is the mantle of the Western taxon or form (all Spring birds). Photo: © A.Corso - courtesy of NHM, Tring

13. An adult ♂ Falco n. naumanni (centre) compared with two ad. ♂♂ “pekinensis” from China, to show how much paler pearl grey is the hood and less saturated, less rusty-vinous but more pinkish tinged is the mantle of the Western taxon or form (all Spring birds). Photo: © A.Corso – courtesy of NHM, Tring

Same birds of fig. 13 in lateral view. Photo: © A.Corso - courtesy of NHM, Tring

Same birds of fig. 13 in lateral view. Photo: © A.Corso – courtesy of NHM, Tring

Advanced 2nd cy ♂ (almost in full 1st adult plumage but for retained juv. S1-S2 and growing P10) ringed at Chockpak Bird Station, Kazakhstan, October.  Intermediate bird with a more saturated colour of the plumage than a typical Western Lesser Kestrel and extensive grey panel on upperwing where however a patch of rusty-vinous terracotta is still visible on inner “harm”.  The origin of this bird (breeding ground) is unknown. Photo: © A.Corso

15. Advanced 2nd cy ♂ (almost in full 1st adult plumage but for retained juv. S1-S2 and growing P10) ringed at Chockpak Bird Station, Kazakhstan, October. Intermediate bird with a more saturated colour of the plumage than a typical Western Lesser Kestrel and extensive grey panel on upperwing where however a patch of rusty-vinous terracotta is still visible on inner “harm”. The origin of this bird (breeding ground) is unknown. Photo: © A.Corso

16.Ad. ♂ (with old P10-P8 and S1-S4) ringed at Chockpak Bird Station, Kazakhstan, October.  A bird very much like Eastern Lesser Kestrel Falco naumanni “pekinensis”-type, with a more saturated colour of the plumage than a typical Western Lesser Kestrel and almost wholly sooty led grey upperwing with a slightly visible rusty tinge on innermost “harm” and on scapulars. The breeding ground of this bird is unknown. On a true Chinese “pekinensis” the rusty tinge will be absent or barely visible and in some even the scapulars would be greyish tinged or grey. However, no birds with such a pattern are found in Europe usually and there are no illustration in any modern field guide showing such a plumage.  Photo: © A.Corso

16. Ad. ♂ (with old P10-P8 and S1-S4) ringed at Chockpak Bird Station, Kazakhstan, October. A bird very much like Eastern Lesser Kestrel Falco naumanni “pekinensis”-type, with a more saturated colour of the plumage than a typical Western Lesser Kestrel and almost wholly sooty led grey upperwing with a slightly visible rusty tinge on innermost “harm” and on scapulars. The breeding ground of this bird is unknown. On a true Chinese “pekinensis” the rusty tinge will be absent or barely visible and in some even the scapulars would be greyish tinged or grey. However, no birds with such a pattern are found in Europe usually and there are no illustration in any modern field guide showing such a plumage. Photo: © A.Corso

Acknowledgments

I wish to thanks as always the Tring, NHM staff to which I am much indebted for the most important help for any of my birds plumages studies. So a warm thanks goes to Katrina Kook, Robert-Pries Johanes, Mark Adams and the others working at Tring and that helped me in various way. On the same way, a warm thanks goes to Dr. Carla Marangoni, curator of the ornithological section at Museo Civico di Zoologia in Roma  (MCZR) for the countless hours of help while I was at the museum among hundreds of skins and specimens. Thanks also to the always kind and helpful Anita Gamauf, curator at the Wien Museum (NMW) and to Prof. Andrei Gavrilov who assisted during the skins study at Almaty Nature Museum of the Zoology Research Institute of the Academy of Science (IZA) and thanks to all the curators of all the other museums where I studied the skins collections in all my visits.

Materials

Birds studied in the field:

60.000+ birds  (MM and FF): in Italy, Spain, Greece, Tunisia, Morocco, Egypt, Sinai, France, Greece, Israel, Turkey, Georgia, Kazakhstan.

Birds studied in the hand (combined skins and ringed birds):

(A)“Falco naumanni pekinensis”:  adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe. For comparison – 40♂♂- from China. (Tring, NHM; Wien, WNHM; Almaty Nature Museum, IZA); birds in the group (E) were not considered for the description of the characters of pekinensis

(B) Falco naumanni ssp. (showing intermediate characters): 75♂♂ ; 27♀♀ – Kazakhstan, Azerbaijan, Turkmenistan.

(C) Falco naumanni  (typical plumage): 270♂♂ ; 82♀♀  – coming from Spain, Italy, Greece, Tunisia, Morocco, Albania, France;

(D) Falco naumanni (both typical naumanni and intermediate birds): 79♂♂ ; 90♀♀  – Turkey, Israel, Egypt, Senegal, Niger, Mauritania, Iraq, Iran, Tanzania, Syria, Lebanon, Jordan, Palestine,  Kirgizstan, Slovenia, South Africa, Check Republic, Georgia.

(E) Falco naumannipekinensis-type”: 10♂♂ from India.

Skins studied preserved at the following museums: Natural History Museum, Tring, England (NHM); Institute of Zoology, Almaty, Kazakhstan (IZA); Museo Civico di Storia Naturale di Milano, Milan, Italy (MCSM); Museo Civico di Terrasini, Palermo, Italy (MCT); Museo Civico dell’Università di Scienze Naturali di Catania, Catania, Italy (MCUCT); Museo Civico di Zoologia di Roma, Rome, Italy (MCZR); Museo Regionale di Scienze Naturali di Torino, Torino, Italy (MRSN); Museo di Storia Naturale “Giacomo Doria”, Genova, Italy (MSNGD); Museo di Storia Naturale “La Specola”, Firenze, Italy (MSNLS); Museo Civico di Storia Naturale di Carmagnola (); Museo Civico di Scienze Naturali “Angelo Priolo”, Randazzo, Italy (MCR); Naturhistorisches Museum Wien, Vienna, Austria (NMW); Nationaal Natuurhistorisch Museum Naturalis, Leiden, the Netherlands (NNM).

References

Ali, S. & S.D. Ripley, 1978. Handbook of the Birds of India and Pakistan. 9: i-xvi, 1-306.— Bombay.

Brown, L. H., and Amadon, D., 1968. Eagles, Hawks and Falcons of the World, vol.1 and 2. Country Life Books, London.

Brown, L. H., Urban, E. K.& Newman, K. 1982. The Birds of Africa. Vol. I. London, UK: Academic Press.

Cheng, Tso-hsin, 1987. A synopsis of the Avifauna of China. i-xvi, 1-1223.— Beijing.

Cheng, Tso-hsin, 1994. A complete checklist of species and subspecies of the Chinese birds. i-xx, 1-

318.— Beijing.

Clark W.S., 1999. A Field Guide to Raptors of Europe, The Middle East and North Africa. Oxford University Press, Oxford.

Corso A., 2000. Less is More: British vagrants, Lesser Kestrel. Birdwatch 91: 29-33.

Corso A., 2001. Notes on the moult and plumages of Lesser Kestrel. British Birds 94: 409-418.

Cramp S & Simmons K.E.L. eds., 1980. The Birds of the Western Palearctic. Vol. 2: Hawks to Bustards.  Oxford University Press, Oxford.

Domaniewski J., 1917: Przyczynek do znajomości form geograficznych Cerchneis naumanni (Fleisch.) [A

contribution to the knowledge of geographic forms of Cerchneis naumanni (Fleisch.)]. – Comptes Rendus

de la Société des Sciences de Varsovie 10 (9):1043-1047. [In Polish.]

Etchécopar, R. D. & Hüe, F., 1978. Les oiseaux de Chine, de Mongolie et de Corée – Vol. I, Non passereaux. Papeete, Tahiti,  Éditions du Pacifique.

Etchécopar, R. D. & Hüe, F. 1964. Les Oiseaux du Nord de l’Afrique, de la Mer Rouge aux Canaries. Paris, France: Editions N. Boubée & Cie.

Ferguson-Lees J. and Christie D.A., 2001. Raptors of the World. Christopher Helm, London.

Forsman D., 1999. The Raptors of Europe and the Middle East. A Handbook of Field Identification. L.T & A.D. Poyser, London.

Grimmett, R., C. Inskipp & T. Inskipp, 1998. Birds of the Indian Subcontinent. 1-888.— London.

Hartert, E., 1913. Die Vögel der paläarktischen Fauna, Heft VIII- p.1081.

Hartert, E. & F. Steinbacher, 1933. Die Vögel der Paläarktischen Fauna. Ergänzungsband. 2: 97-192.— Berlin.

Hodgson, B.H., 1844. Catalogue of Nipalese Birds collected between 1824 and 1844.— [Gray’s] Zoological

Miscellany: 81-86.

Hodgson, B.H., 1845a. Characters of six new species of Nepalese birds.— Ann. Mag. Nat. Hist., (1) 15 (99): 326-327.

Hodgson, B.H., 1845b. [On Nepalese birds.].— Proc. Zool. Soc. Lond.: 22-37.

Hodgson, B.H., 1855. Catalogue of Nipalese Birds, collected between 1824 and 1844.— J. Asiatic Soc.

Bengal, 24 (7): 572-582.

Jerdon,T. C., 1871. Supplementary Notes to ‘The Birds of India’. Ibis 13: 335–356.

Inskipp, T.P., N. Lindsey & J.W. Duckworth, 1996. An Annotated Checklist of the Birds of the Oriental

Region. [i-x], 1-294.— Sandy, Beds., UK.

Rasmussen, P. C. & Anderton, J. C., 2005. Birds of South Asia: the Ripley guide. Barcelona, Lynx Editions.

Ripley, S.D., 1982. A synopsis of the birds of India and Pakistan together with those of Nepal, Bhutan,

Bangladesh and Sri Lanka. i-xxvi, 1-653.— Bombay.

Sharpe, R.B., 1874. Catalogue of the birds in the British Museum. I. Catalogue of the Accipitres or diurnal birds of prey in the collection of the British Museum.— London, Taylor & Francis.

Snow D.W. & Perrins C.M., 1998. Birds of the Western Palearctic: concise edition. Vol 1 – Non-Passerines. Oxford University Press, Oxford.

Swinhoe, R., 1870. Zoological notes of a journey from Canton to Peking and Kalgan.— Proc. Zool. Soc.

Lond.: 427-451.

Swinhoe, R. 1871. A Revised Catalogue of the Birds of China and its Islands, with Descriptions of New Species, References to former Notes, and occasional Remarks. Proc. Zool. Soc. Lond.: 337-423.

Vaurie, C., 1965. The Birds of the Palearctic Fauna. A systematic reference. Non-Passeriformes: i-xxi, 1-

763.— London.

Zarudny, N.A., 1912. On the Ornithology of Turkestan – Urinator arcticus suschkini and Cerchneis naumanni turkestanicus subspp. nov. Ornithologische Mitteilungen : 114.

Warren, R.L.M., 1966. Type-specimens of birds in the British Museum (Natural History). 1: i-x, 1-

320.— London.

Warren, R.L.M. & C.J.O. Harrison, 1971. Type-specimens of birds in the British Museum (Natural History).

2: i-vi, 1-628.— London.

Warren, R.L.M. & C.J.O. Harrison, 1973. Type-specimens of birds in the British Museum (Natural History).

3: i-xii, 1-76.— London.

–          APPENDIX I

LESSER KESTREL NOMENCLATURE  (synonym)

FALCO NAUMANNI  (Fleischer, 1818)

–          Falco naumanni [as Naumanni] J.G.Fleischer, 1818 – in Laurop & Fischer, Sylvan. Ein Jahrbuch für Forstmänner,Jäger und Jagdfreunde auf das Jahr 1818, p.174. (“spärlicher Gast im südl. Deutschland und Schweiz”; error for Sicily, fide Stresemann (MS))

Falco xantonyx [as Xantonyx] J.G.Fleischer(ex Natterer MS), 1818- in Laurop & Fischer, Sylvan. Ein Jahrbuch für Forstmänner, Jäger und Jagdfreunde auf das Jahr 1818, p.175. (= F.naumanni)

Falco tinnunculoides Temminck (ex Natterer MS) (1820) – Manuel d’ornithologie, ou Tableau systématique des oiseaux qui se trouvent en Europe…,2nd edn,1,p.30. (“Hongrie,Autriche-Naples-Sicile-Sardaigne-Espagne”). (= F.naumanni)

Falco cenchris Frisch (1820) – in J.F.Naumann, Johann Andreas Naumann’s mehrerer gelehrten Gesellschaften Mitgliede, Naturgeschichte der Vögel Deutschlands ,2nd edn,1,p.318,pl.29. (Italy,Austria,Tyrol,Switzerland,Savoy,Piedmont).

Falco xanthonyx Naumann (ex Natterer MS) (1822) – Johann Andreas Naumann’s mehrerer gelehrten Gesellschaften Mitgliede,Naturgeschichte der Vögel Deutschlands…,1,p.323. (= F.naumanni)

Falco tinnuncularius Roux,1825 – Ornithologie provençale;ou description…de tous les oiseaux qui habitent constamment la Provence,ou qui n’y sont de passage,1,p.60,pls.40,41. (Provence). (= F.naumanni)

Falco subtinnunculus C.L.Brehm (1827) – Ornis,3 Heft,p.12. (Egypt and southern European islands). (= F.naumanni)

Cerchneis cenchris C.L.Brehm (1831) – Handbuch der Naturgeschichte aller Vögel Deutschlands,p.74. (= F.naumanni)

Tinnunculus cenchris Bonaparte (1842) – Catalogo Metodico degli Uccelli di Europa, p.21. (= F.naumanni)

Tichornis cenchris Kaup (1844) – Classification der Säugethiere und Vögel,p.108. (= F.naumanni)

Poecilornis cenchris Kaup, 1850 in W.Jardine(ed.) – Contributions to Ornithology for 1850,p.53. (= F.naumanni)

Cerchneis paradoxa C.L.Brehm, 1855- Der Vollständige Vogelfang,p.29. (Greece). (= F.naumanni)

Cerchneis ruficeps C.L.Brehm,1855,Naumannia, p.269. (= F.naumanni)

Cerchneis ruficauda C.L.Brehm,1855, Naumannia, p.269. (= F.naumanni)

Erythropus cenchris Jerdon , 1862 – The Birds of India, 1, p.38. (= F.naumanni)

Falco naumanni naumanni – Hartert,1913 [“1921”], Die Vögel der paläarktischen Fauna,Heft VIII(Aug.),p.1080. (= F.naumanni)

Cerchneis naumanni  – Sharpe (1874) – Catalogue of the Birds in the British Museum,1, Accipitres or Diurnal Birds of Prey, p.435. (= F.naumanni)

Falco cenchris var. pekinensis Swinhoe (1870). Proceedings of the Zoological Society of London,p.442. (near Peking).(= F. naumanni pekinensis)

Tichornis pekinensis Swinhoe (1871). Proceedings of the Zoological Society of London,p.341. (= F. naumanni pekinensis)

Cerchneis pekinensis in Sharpe (1874). Catalogue of the Birds in the British Museum,1, Accipitres or Diurnal Birds of Prey,p.437. (= F.naumanni pekinensis )

Erythropus pekinensis in Jerdon (1871). Ibis,p.242. (= F.naumanni pekinensis)

Falco naumanni pekinensis Hartert 1913 [“1921”], Die Vögel der paläarktischen Fauna, Heft VIII(Aug.),p.1081. (= F.naumanni pekinensis)

Cerchneis angolensis Bocage, 1876 – Jornal de Sciencias mathematicas,physicas e naturas, publicado sob os auspicos da Academia real das sciencias da Lisboa 5: 153. (Huilla in Angola). (= F.naumanni)

Cerchneis naumanni turkestanicus Zarudy, 1912 – Ornithologische Mitteilungen, p.114. (= F.naumanni ssp.)

Cerchneis naumanni sarmaticus Domaniewski, 1917 – Compt. Rend. Soc. Sci. Varsovie, X, p. 1044. (= F.naumanni)

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.