A report from the British Ornithologists’ Union Taxonomic Sub-committee The taxonomic status of Macqueen’s George Sangster, Martin Collinson, Andreas J. Helbig, Alan G. Knox and David T. Parkin

32. Macqueen’s Bustard Chlamydotis macqueenii, Mangyshlak, western Kazakhstan, May 1996. An incubating female in Artemisia (wormwood) steppe, fairly typical breeding habitat of this species in Kazakhstan. Simon Aspinall

ABSTRACT For much of the twentieth century, Macqueen’s Bustard Chlamydotis macqueenii was treated as a subspecies of Chlamydotis undulata, but recent studies of courtship behaviour, vocalisations, and mitochondrial and nuclear DNA have shown consistent differences between Macqueen’s and Houbara Bustard.Together with clear-cut plumage differences, these new data suggest that Macqueen’s and Houbara Bustard are best treated as separate species.The Canary Islands population of Houbara (C. u. fuertaventurae) is not safely diagnosable from populations in Northern Africa (C. u. undulata) at present, and, based on current knowledge, these populations are best treated as a single species.

60 © British 97 • February 2004 • 60-67 The taxonomic status of Macqueen’s Bustard

he ‘Houbara Bustard Chlamydotis undu- been suggested that macqueenii and undulata lata’ is widespread across arid, semi- may have been in contact in the recent past Tdesert regions of the Palearctic, from the (Gaucher et al. 1996). Atlantic coast of Africa (including three of the This conventional treatment of the Canary Islands) to Mongolia. This distribution ‘Houbara’ group is based on the Polytypic is fragmented, however, and consists of a series Species Concept, which generally regards closely of more-or-less isolated populations (fig. 1; see related, non-overlapping taxa as subspecies of a also Cramp & Simmons 1980). Conventional polytypic species; this classification was wisdom has regarded this as a polytypic species, assumed to be consistent with the Biological comprising three subspecies: C. u. macqueenii Species Concept. Recent research has, however, (hereafter macqueenii) in eastern Egypt (Sinai), cast new light upon the courtship, vocalisations Arabia and central Asia from northwest Kaz- and genetic variation of the Houbara taxa. This akhstan east to Mongolia, wintering from the research, combined with revised views of Persian Gulf to northwest India and in central species limits (e.g. Helbig et al. 2002), suggests China; C. u. undulata (hereafter undulata) in that the traditional interpretation may no northern Africa from Mauritania to western longer be tenable. This paper summarises the Egypt; and C. u. fuertaventurae (hereafter fuer- evidence for taxonomic differentiation in this taventurae) on Fuertaventura, Lanzarote and complex, extending the review by Sangster Graciosa, in the Canary Islands. At present, (1996). there is no contact at all among the popula- tions: they are entirely allopatric. Indeed, we Recent research findings know of no evidence that macqueenii, fuer- Plumage and courtship taventurae and undulata have ever been sym- of the Houbara group are gregarious patric (i.e. with populations overlapping), or outside the breeding season, but solitary and even parapatric (i.e. with populations coming territorial when breeding (Cramp & Simmons into contact, but not coexisting), although it has 1980). Courtship display is by the male and is

Fig. 1. Map showing world distribution of the three taxa in the Houbara complex: Houbara Bustard Chlamydotis undulata of the nominate race and the Canary Islands form fuertaventurae, and Macqueen’s Bustard C. macqueenii.

British Birds 97 • February 2004 • 60-67 61 The taxonomic status of Macqueen’s Bustard

Table 1. Acoustic characters of display calls of Houbara Bustard Chlamydotis undulata and Macqueen’s Bustard C. macqueenii (from Gaucher et al. 1996, modified where appropriate).

Vocal parameter undulata macqueenii

Duration of the phrase or series 5.4-9 s* 12-18 s** Number of notes per series 3-5*** 25-40 Variation of melodic structure during a series No Yes Variation of intensity during a series No Yes Variation of rhythm during a series No Yes Average length of a note including intermediate silence 2.25 s 0.43 s Length of the note 0.45 s 0.24-0.33 s Length of intermediate silence 1.8 s 0.18-0.09 s Silence/note ratio 4 0.5 Frequency variation during the note No Decreasing Number of vibrations during the note 42-45 21-25 * Gaucher et al. (1996) stated that the phrase lasts 9 seconds, but a published recording (Chappuis 2000) includes a three-note phrase lasting 5.4 seconds. ** Table 1 in Gaucher et al. (1996) shows a range of 12-13 seconds, but this is probably a typographic error because a range of 12-18 seconds was given in their main text, which is consistent with a published recording (Chappuis 2000). *** Gaucher et al. (1996) stated that there are four notes, but two phrases in a published recording (Chappuis 2000) show only three notes, and a sonogram illustrating a five-note phrase was presented in Gaucher et al. (1996, fig. 7). curtailed after pair-formation, which suggests Vocalisations that its role is predominantly to attract a If no potential partner is close to the displaying female. Key components of the display include male, he begins to call. Although audible to the feathers on the neck and head becoming observers up to 50 m away, this part of the erect and the adoption of postures which make display was apparently unreported until Alek- the male highly conspicuous. Gaucher et al. seev (1985) recorded it in macqueenii. Gaucher (1996) studied the behaviour and vocalisations et al. (1996) reported that calls during display of of macqueenii and undulata, both in the field undulata and macqueenii differ in no less than and in captivity, and reported differences in 11 vocal parameters (table 1, fig. 2). For certain visual aspects of the courtship display. example, undulata typically utters a series of The filamentous feathers on the sides of the four notes, which together last nine seconds, neck are black in undulata, but black-and-white whereas macqueenii typically gives a series of in macqueenii. Furthermore, the crest of undu- 25-40 motifs and notes, lasting 12-18 seconds. lata is white and remains erect during display, During a series, the notes of macqueenii show while that of macqueenii is black-and-white and variation in melodic structure, intensity and falls over the bill. These differences in the rhythm, whereas no such variation has been colour of the feathers and the position in which reported in undulata. The display calls of fuer- they are held during display (see drawings in taventurae were not studied by Gaucher et al. Gaucher et al. 1996, and colour photos in Sang- (1996) and have not been analysed in detail. ster 1996) seem to be diagnostic. During the running phase of the display, undulata runs Variation in enzymes almost as fast as macqueenii, but the neck is The variation within and between populations or reported to swing with a greater amplitude in higher taxa can be analysed by screening geneti- macqueenii than in undulata (although quanti- cally variable enzyme loci. A comparison of the tative data were not given by Gaucher et al.). In gene (allele) frequencies of different enzymes fuertaventurae, the frills on the sides of the neck allows an estimate to be made of the amount of are black (and thus similar to those of differentiation between two populations. undulata). Gaucher et al. did not study the Granjon et al. (1994) carried out such a compar- courtship behaviour of fuertaventurae,but ison by applying Nei’s coefficient of genetic dis- descriptions in an earlier study by Hinz & Heiss tance to 31 enzyme genes of macqueenii from (1989) indicate that it is closely similar to that Pakistan (n=22) and undulata from Algeria of undulata. (n=17); they concluded that there is a ‘high

62 British Birds 97 • February 2004 • 60-67 The taxonomic status of Macqueen’s Bustard genetic identity… between the two subspecies’. their similarity to group taxa into clusters that Further details are presented in Appendix 1. are considered to reflect their evolutionary history. Phylogenetic analysis of the Houbara Mitochondrial-DNA sequences Bustard sequences showed that eastern birds Gaucher et al. (1996) sequenced 300 base pairs clustered together into a macqueenii group, of the mitochondrial-DNA (mtDNA) genome clearly separate from western birds, which clus- from individuals of macqueenii from Pakistan, tered together into an undulata group. The dis- Saudi Arabia and Sinai, and undulata from tinctness of these groups indicated that each has Algeria. DNA sequences can be analysed using a a separate common ancestor, thus supporting technique called ‘neighbour-joining’, which uses the division of the two based on morphology.

3 Fig. 2a 2.5 2 1.5 1

Frequency kHz Frequency 0.5 0 1 2 3 4 5 6 7 8 9 1011121314151617 Time (sec)

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0.5

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-1 1234567891011121314151617 Time (sec)

3 Fig. 2b 2.5 2 1.5 1

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1

0.5

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-1 1234567891011121314151617 Time (sec) Fig. 2. Sonograms (above) and oscillograms (below) of a complete phrase of the display call of captive male Macqueen’s Bustard Chlamydotis macqueenii (2a) and Houbara Bustard C. undulata (2b). Recordings were taken from Chappuis (2000); sonograms were made using Syrinx (Burt 2001).

British Birds 97 • February 2004 • 60-67 63 The taxonomic status of Macqueen’s Bustard

The work indicated that the undulata and mac- Sinai, and undulata from Algeria, using well- queenii clusters comprise separate evolutionary established methodologies. In summary, the lineages. No differences were found between the results showed consistent differences between mtDNA sequences of undulata and fuertaven- undulata and macqueenii, with the two taxa turae.Broders et al. (2003) extended the study forming separate monophyletic clusters, thus of Gaucher et al. (1996) and confirmed that supporting the results of Gaucher et al. (1996), there are consistent differences between undu- Pitra et al. (2002) and Broders et al. (2003). lata/fuertaventurae and macqueenii. Further details are presented in Appendix 3. Pitra et al. (2002) analysed the mtDNA of more than 20 species of bustards, including all Discussion three forms traditionally lumped under Diagnosability Houbara; they confirmed that undulata and In an attempt to bring a degree of consistency fuertaventurae are sister taxa, but that mac- to its deliberations, the BOU Taxonomic Sub- queenii is more divergent. They suggested that committee drew up a set of ‘Guidelines’ to help undulata/fuertaventurae differ from macqueenii in defining species limits (Helbig et al. 2002). by about as much as, for example, Buff-crested Key to these deliberations are (1) whether or Lophotis gindiana and Savile’s Bustards L. savilei not the taxa are diagnosably distinct, and (2) or Australian Ardeotis australis and Great Indian whether they represent independent evolu- Bustards A. nigriceps differ from each other. tionary units (lineages, following de Queiroz Idaghdour et al. (2004) recently published the 1999). results of another molecular study of the Macqueenii and undulata evidently possess Houbara group. They sequenced 854 base pairs different morphological, behavioural and vocal of the mitochondrial control region from 73 characteristics which are diagnostic, and molec- individuals of all three taxa. Again, their results ular analyses of mitochondrial and nuclear confirm that fuertaventurae and undulata are DNA show that they form two clearly distinct weakly differentiated, but that these taxa are (monophyletic) units (or clades). Although the clearly distinct from macqueenii. Further details molecular differences are small, they are within are presented in Appendix 2. the range considered acceptable for separating closely related non-passerine species (e.g. Avise Nuclear and mitochondrial-DNA analyses & Zink 1988, Shields 1988, Seibold et al. 1996). In an attempt to test whether the subpopula- The evidence that the populations of tions of macqueenii are genetically distinct, Houbara Bustard on the Canary Islands are D’Aloia (2001) carried out analyses of mtDNA diagnosably distinct is not conclusive. Cur- of macqueenii from China, Pakistan, rently, fuertaventurae is recognised on the basis Afghanistan, eastern and western Kazakhstan, of minor quantitative differences from Iran, Oman, Abu Dhabi, Saudi Arabia and undulata, such as its smaller size and darker plumage. These differences may be the result of ecological factors. Although sample sizes are small, mtDNA sequences of the North African and Canary Islands populations appear to be identical (Gaucher et al. 1996; Broders et al. 2003), which can be explained either by recent colonisation of the Canary Islands from North Africa, or by recent or continuing gene flow between the two regions (Gaucher et al. 1996). The differences in behav- Richard Smith 33. Houbara Bustard Chlamydotis undulata, of the Canary Islands population iour and morphology between C. u. fuertaventurae, Lanzarote, February 2000. macqueenii and undulata, and

64 British Birds 97 • February 2004 • 60-67 The taxonomic status of Macqueen’s Bustard their molecular separation into two distinct the conclusion that undulata and macqueenii groups, indicate that these are separate evolu- are best treated as species also follows if the tax- tionary lineages. The lack of published evidence onomic criteria of other species concepts are for diagnostic differences within either undulata applied. For instance, because they represent or macqueenii suggests that, at present, no other populations which are clearly diagnosable in populations in the complex qualify as distinct several morphological, behavioural, vocal and species following the guidelines of Helbig et al. molecular characters, they qualify as species (2002). under the Phylogenetic Species Concept (Cracraft 1983). Because undulata and mac- Reproductive isolation queenii form separate, monophyletic groups of Behavioural characters are often superior to populations and are diagnosable by several morphological characters in the study of the characters, they would be treated as species level of reproductive isolation in closely related under a different version of the Phylogenetic species (Mayr 1963). The additional evidence Species Concept (Mishler & Theriot 2000), a reported by Gaucher et al. (1996) allows us to version perhaps more appropriately known as re-examine the taxonomic status of Houbara the ‘Monophyletic Species Concept’ (Davis Bustards because courtship is directly involved 1997; Hull 1997). Under the Recognition in pair-formation and often forms a reliable Species Concept (Paterson 1985), undulata and indicator of species recognition in the birds macqueenii would probably be treated as dif- themselves. Although there are no data to indi- ferent species because their pair-formation cate whether female undulata would respond to mechanisms differ. Based on these differences in the display of male macqueenii, and vice versa, pair-formation mechanisms, a case can be made the evidence that the pair-formation mecha- that undulata and macqueenii are reproduc- nisms of these taxa differ in several ways sup- tively isolated and that they probably qualify as ports their treatment as separate species. Only species under the Biological Species Concept experimental tests of mate choice in Chlamy- (Mayr 1970). Consequently, we believe that the dotis bustards can confirm whether the behav- treatment of undulata and macqueenii as ioural differences indeed prevent the formation species does not depend critically on the choice of mixed pairs. of species concept.

Taxonomy Acknowledgments The three subspecies of ‘Houbara Bustard’ are We thank an anonymous referee whose comments on an allopatric, and, following the guidelines of earlier draft have improved this paper. Helbig et al. (2002), closely related allopatric References taxa should be regarded as separate species only Alekseev, A. F. 1985.The Houbara Bustard in the north- if they are fully diagnosable in each of several west Kyzylkum. Bustard Studies 3: 87-92. discrete or continuously varying characters Avise, J. C., & Zink, R. M. 1988. Molecular genetic related to different functional contexts (Helbig divergence between avian sibling species: King and Clapper Rails, Long-billed and Short-billed Dowitchers, et al.’s condition 4.1). It is now established that Boat-billed and Great-tailed Grackles, and Tufted and macqueenii and undulata possess different and Black-crested Titmice. Auk 105: 516-528. fully diagnosable morphological, behavioural, Barrowclough, G. F. 1980. Genetic and phenotypic vocal and molecular characters. There is, differentiation in a wood warbler (genus Dendroica) hybrid zone. Auk 97: 655-668. however, no evidence to suggest that fuertaven- Broders, O., Osborne,T., & Wink, M. 2003. A mtDNA turae is diagnosably distinct from undulata. phylogeny of bustards (family Otididae) based on Based on these considerations and the available nucleotide sequences of the cytochrome b gene. J. Ornithol. 144: 176-185. evidence, we recommend that the Houbara Burt, J. 2001. Syrinx Version 2.2b. http://SyrinxPC.com complex be treated as two species: Houbara Chappuis, C. 2000. African Sounds 1: Birds of North, Bustard Chlamydotis undulata (with the sub- West and Central Africa. Societe Ornithologiques de species undulata and fuertaventurae) and Mac- France in collaboration with The British Library National Sound Archive, Paris and London. queen’s Bustard C. macqueenii (monotypic). Cracraft, J. 1983. Species concepts and speciation analysis. Although the guidelines of Helbig et al. Current Ornithology 3: 159-187. (2002) are consistent with the Evolutionary Cramp, S., & Simmons, K. E. L. (eds.) 1980. The Birds of the Western Palearctic.Vol. 2. OUP,Oxford. Species Concept (Mayden 1997) and the D’Aloia, M.-A. 2001. Studies of the population structure of General Lineage Concept (de Queiroz 1999), the Houbara Bustard Chlamydotis undulata in the

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Middle East with DNA analysis techniques. Zool. Middle Mayden, R. L. 1997. A hierarchy of species concepts: the East 22: 25-35. denouement in the saga of the species problem. In: Davis, J. I. 1997. Evolution, evidence, and the role of Claridge, M. F., Dawah, H. A., & Wilson, M. R. (eds.), species concepts in phylogenetics. Syst. Bot. 22: 373- Species: the units of biodiversity: 381-424. Chapman & 403. Hall, London. de Queiroz, K. 1999.The general lineage concept of Mayr, E. 1963. Species and Evolution. Harvard species and the defining properties of the species University Press, Cambridge, Mass. category. In:Wilson, R. A. (ed.), Species: new — 1970. Populations, Species, and Evolution. Harvard interdisciplinary essays: 49-89. MIT Press, Cambridge, University Press, Cambridge, Mass. Mass. Mishler, B. D., & Theriot, E. C. 2000.The Phylogenetic Gaucher, P.,Paillat, P., Chappuis, C., Saint Jalme, M., Species Concept (sensu Mishler and Theriot): Lotfikhah, F., & Wink, M. 1996. of the Monophyly, Apomorphy, and Phylogenetic Species Houbara Bustard Chlamydotis undulata subspecies Concepts. In:Wheeler, Q. D., & Meier, R. (eds.), Species considered on the basis of sexual display and genetic concepts and phylogenetic theory: a debate: 44-54. divergence. Ibis 138: 273-282. Columbia University Press, New York. Granjon, L., Gaucher, P.,Greth, A., & Vassart, M. 1994. Moreno, J. M. 2000. Canto y Reclamos de las Aves de Allozyme study of two subspecies of Houbara Bustard Canarias.Turquesa Ediciones, Santa Cruz de Tenerife. (Chlamydotis undulata undulata and C. u. macqueenii). Paterson, H. E. H. 1985.The recognition concept of Biochem. Syst. Ecol. 22: 775-779. species. In:Vrba, E. (ed.), Species and speciation: 21-29. Helbig, A. J., Knox, A. G., Parkin, D.T., Sangster, G., & Transvaal Museum, Pretoria. Collinson, M. 2002. Guidelines for assigning species Pitra, C., Lieckfeldt, D., Frahnert, S., & Fickel, J. 2002. rank. Ibis 144: 518-525. Phylogenetic relationships and ancestral areas of the Hillis, D. M., Moritz, C., & Mable, B. K. (eds.) 1996. bustards (Gruiformes: Otididae), inferred from Molecular Systematics. 2nd edn. Sinauer, Sunderland, mitochondrial DNA and nuclear intron sequences. Mass. Mol. Phylogen. Evol. 23: 63-74. Hinz, C., & Heiss, E. M. 1989.The activity patterns of Sangster, G. 1996.Taxonomy of Houbara and Macqueen’s Houbara Bustards: aspects of a field study in the Bustards and neglect of intraspecific diversity. Dutch Canary Islands. Bustard Studies 4: 68-79. Birding 18: 248-254. Hull, D. L. 1997.The ideal species concept – and why we Seibold, I., Helbig, A. J., Meyburg, B. U., Negro, J. J., & Wink, can’t get it. In: Claridge, M. F., Dawah, H. A., & Wilson, M. M. 1996. Genetic differentiation and molecular R. (eds.), Species: the units of biodiversity: 357-380. phylogeny of European Aquila eagles (Aves: Chapman & Hall, London. Falconiformes) according to cytochrome-b nucleotide Idaghdour,Y., Broderick, D., Korrida, A., & Chbel, F. 2004. sequences. In: Meyburg, B. U., & Chancellor, R. D. (eds.), Mitochondrial control region diversity of the Houbara Eagle Studies: 1-15.World Working Group on Birds of Bustard Chlamydotis undulata complex and genetic Prey and Owls, Berlin. structure along the Atlantic seaboard of North Africa. Shields, G. F. 1988. Evolution of mitochondrial DNA in Mol. Evol. 13: 43-54. geese. Proc. Int. Ornithol. Congr. 19: 1889-1895.

George Sangster, Stevenshof 17, 2312 GM Leiden, The Netherlands; e-mail: [email protected] (corresponding author) Dr Martin Collinson, Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD Prof. Andreas J. Helbig, Universität Greifswald, Vogelwarte Hiddensee, D-18565 Kloster, Germany Dr Alan G. Knox, Historic Collections, King’s College, University of Aberdeen, Aberdeen AB24 3SW Prof. David T. Parkin, Institute of Genetics, University of Nottingham, Queen’s Medical Centre, Nottingham NG7 2UH

Appendix 1 (>5%). Private alleles are examples of genetic Variation in enzymes variants which are present in one population or Nei’s coefficient of genetic distance has been taxon and absent from another. They are used previously to compare the gene (allele) regarded as evidence for the absence of gene frequencies of different enzymes among a range flow between the populations, since coexistence of avian groups (see Barrowclough 1980). usually results in alleles being passed between Granjon et al. (1994) applied this technology to individuals by sexual reproduction. The genetic 31 enzyme genes of macqueenii from Pakistan distance between macqueenii and undulata, (n=22) and undulata from Algeria (n=17). measured by Nei’s coefficient, was 0.008, and Thirteen of these loci were genetically variable led Granjon et al. (1994) to conclude that there (polymorphic). No diagnostic alleles were is a ‘high genetic identity… between the two found, i.e. at no enzyme locus was one form subspecies’. A genetic distance of 0.008 is at the found exclusively in macqueenii and another in lower end of values for taxa known on other undulata. Three ‘private’ alleles were, however, grounds to be separate species (Barrowclough found in each, two at quite high frequency 1980).

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Appendix 2 (Broders et al. 2003). Mitochondrial-DNA sequences Pitra et al. (2002) examined two separate Gaucher et al. (1996) sequenced 300 base pairs genes from the mitochondrial genome, plus a of the mtDNA genome from individuals of nuclear sequence, but only the mitochondrial macqueenii from Pakistan, Saudi Arabia and cytochrome b gene (444 base pairs) was Sinai, and undulata from Algeria. An analysis screened in these three taxa. Although their using the ‘neighbour-joining’ technique sug- primary objective was to resolve the evolu- gested that the macqueenii clade and the undu- tionary history of the whole bustard family, and lata clade comprise separate evolutionary to establish the authenticity of the various lineages, and that the genetic distance between genera within the bustards, they confirmed that the two was 0.7-1.1%. No differences were undulata and fuertaventurae are sister taxa, and found between the mtDNA sequences of undu- that macqueenii is more divergent. lata and fuertaventurae. Broders et al. (2003) extended the study of Appendix 3 Gaucher et al. (1996) and confirmed that there Nuclear and mitochondrial-DNA analyses are consistent differences between D’Aloia (2001) carried out RAPD (Randomly undulata/fuertaventurae and macqueenii.They Amplified Polymorphic DNA; Hillis et al. 1996) sequenced 1,143 base pairs of the mitochon- analyses of nuclear DNA, and SSCP (Single drial cytochrome b gene. In addition to the Stranded Conformational Polymorphism; Hillis localities sampled by Gaucher et al., this study et al. 1996) analyses of mtDNA of macqueenii also included samples of macqueenii from Kaz- from China, Pakistan, Afghanistan, eastern akhstan. Their results show that mtDNA Kazakhstan, western Kazakhstan, Iran, Oman, sequences of undulata and macqueenii differ by Abu Dhabi, Saudi Arabia and Sinai, and undu- 1.7-1.9%, whereas those of undulata and fuer- lata from Algeria. These analyses were directed taventurae are identical. Individuals of mac- towards different molecular sequences from queenii from Sinai, Egypt, formed a separate those in the previous studies and, even though cluster in these mtDNA sequence studies, but they all involve molecular data, they can be this was based on differences in a single base regarded as independent lines of evidence. pair (Gaucher et al. 1996) or three base pairs The RAPD data supported the results of Gaucher et al. (1996), Pitra et al. (2002) and Broders et al. (2003) in showing consistent differences between undulata and macqueenii, with the two taxa forming separate mono- phyletic clusters. The RAPD analysis revealed several poly- morphisms in the macqueenii samples but none was specific to any geographic population. The SSCP analyses gave similar results. All undulata were of one type and all mac- queenii were of another type. There was no variation within macqueenii: no differences were found between birds from the Sinai population and those from other Arabian or Asian populations. Although the sample sizes are small, the SSCP data show that there are Marcus Lawson 34 Houbara Bustard Chlamydotis undulata, of the Canary Islands consistent differences between population C. u. fuertaventurae, Fuerteventura, December 2002. the two taxa.

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