AUSTRALIAN 60 WATCHER

AUSTRALIAN BIRD WATCHER 1993, 15, 60-67

Comments on the Taxonomic Position of the roseicapilla

by JOHN COURTNEY, 'Ashgrove', Swan Vale, via Glen Innes, N.S.W. 2370

Summary Behavioural and morphological features of the Cacatua were examined in an attempt to identify characters diagnostic for the genus, and thereby clarify the taxonomic position of the Galah Cacatua roseicapilla. It is shown that the Galah has 9 out of 10 'definitive Cacatua characteristics', the same score as seven other . The remaining five species may possess all 10 characters. On these 'traditional' criteria, the Galah falls well within Cacatua, a result in agreement also with biochemical data.

Introduction Ideally, in taxonomic decisions involving change, both sides of the case ought to be examined before a decision is made. Unfortunately this does not always happen, and the transfer of the Galah Cacatua roseicapilla from Cacatua to the monotypic genus Eolophus appears to be an example of such. This proposed change has been based on the differences between the Galah and other members of Cacatua, and disregards the many features shared in common, which may indicate relationship. This preoccupation with differences to the exclusion of all similarities puts such a one­ sided case that this paper is presented in order to show that another side exists, and to try to examine the question in general. In this paper, Cacatua is used in the modern sense as encompassing all the former 'white' cockatoo genera (e.g. Plyctolophus, Ducorpsius) , which have been synonymised with it. Thus, 'typical Cacatua' encompasses characters shared by the thirteen species of the genus as presently constituted, and is not restricted here to mean characters of the type species of Cacatua, C. alba (Muller) ( = Cacatua cristata Vieillot). Resume of taxonomic position of Galah Increasing confusion surrounds the question as to whether the Galah should be included in Cacatua or separated generically in monotypic Eolophus. To use Cacatua when discussing the phylogeny of the Galah, and Eolophus to emphasise its supposed differences in behaviour and morphology, is not sustainable or reasonable and this question must be resolved. This can only be done by examining the evidence for and against. A starting point is the relevant literature, and the following resume is intended only to explain previous moves leading to present uncertainty; it is not intended as a complete review. Traditionally, the Galah has been regarded as a member of the 'white' cockatoo genus known variously as Kakatoe or Cacatua. Gould (1865) and four major checklists, Anon. (1913), Anon. (1926), Peters (1937) and Condon (1975), have all placed it thus, and most literature followed suit. However, some authors dissented. Mathews (1916, and in many of his other publications) used Eolophus, citing as reasons its distinct colour, small and stout bill, and wing shape (long primaries, pointed wing tip and short secondaries). Vane (19?9) also used Eolophus in his review of the , because of its grey and pink coloration (however, perceiving relationships, he also confusingly included the short-billed corellas in Eolophus but under a separate subgenus). VOL. 15 (2) JUNE 1993 Taxonomic Position of Ga1ah 61

Forshaw (1963) was the first of the modem authors to contest forcefully the inclusion of the Galah in Cacatua and, on the grounds of some differences in flight , behaviour and colour of plumage, formally moved to have the Galah transferred to the monotypic genus Eolophus Bonaparte (1854). Forshaw (1969, 1973) continued with this view. Curiously, this move was not mentioned by Lendon (1973) who unquestioningly retained the Galah in Cacatua, even though Holyoak (1970) had previously documented further differences (cranial and colour) and supported Forshaw. Lendon did, however, acknowledge the arrangement of Vane (1959) but declined to abide by it. Forshaw (1978, 1981) persevered with Eolophus. Perhaps the most dramatic tum of events in the continuing saga was the result of a biochemical study of the systematics of the Australian cockatoos by Adams et al. (1984): they flatly stated that the Galah is not only a member of Cacatua , but is very closely related to the complex within that genus. Following this Schodde & Tidemann (1986), at that time a reliably up-to-date publication, used Cacatua. Then, foreshadowing moves to come, Schodde (1988) provisionally used Eolophus and stated that it was placed in its own monotypic genus because of its colour pattern, pink­ downed nestlings and distinctive skull, and gave Hornberger & Schodde (in prep.) as a reference. Forshaw (1989) continued using Eolophus. Rowley (1990) followed suit and used Eolophus, but without giving taxonomic opinion other than to quote Forshaw (1981) and Schodde (1988). Finally (with Hornberger & Schodde still 'in prep.'), Christidis et al. (1991) qsed Cacatua fqr the Galah, without comment on any need for its separation from Cacatua. Furthermore, the genetic distance they recorded between the Sulphur-crested Cockatoo Cacatua galerita and Galah was of a similar magnitude to that obtained within other genera.

Methods From 1952 to the present, young of many species of Australian and cockatoos were hand­ reared by me, in order to record their juvenile food-begging calls and related behaviour, and to note colour changes of plumage and soft parts from chick to adult (see Courtney 1974, 1975, 1986a,b). Data from this source, plus the available literature and information supplied by colleagues, were examined in an attempt to identify characters diagnostic of the genus Cacatua, and thereby clarify the position of the Galah. Ten readily observable behavioural and morphological characters were identified as being shared by Cacatua (in the modern sense) plus the Galah, but not found in other cockatoo genera, with one notable exception: one or two of these characters are present also in Probosciger.

Differences in Galah from other Cacatua The unique combination of grey and pink in adult plumage of the Galah is well known. Its manner of flight, too, is distinctive in Jacking brief glides often used by other Cacatua cockatoos and in being faster and stronger. The pink colour of the natal down of nestlings of the Galah is different from other cockatoos (Courtney 1965). Unlike all other members of Cacatua, the Galah Jacks yellow in its plumage (Holyoak 1970). Schodde (1988) indicated that there is a difference in colour pattern (presumably the near-white patches on rump and upperwings), and that the skull of the Galah has well-developed maxillary processes and reduced temporal fossae.

Similarities in Galah to other Cacatua Examination of the genus shows that there are ten diagnostic characters that collectively separate the group from all other cockatoo genera. Other diagnostic characters for the genus Cacatua may remain to be defined. Those examined were as follow. (1, 2 & 3). Young of the genus possess a three-factor combination of recognisable Cacatua juvenile food-begging call, higher-pitched breath-drawing note sandwiched AUSTRALIAN 62 COURTNEY BIRD WATCHER

between begging notes, and a rhythmic swaying begging posture of the young, none of which occurs in any other cockatoo (or parrot), except for a trace (?) of factors 1 and 2 in the Probosciger aterrimus. The young of all Australian parrots and cockatoos possess juvenile food-begging calls, which differ greatly between genera and especially between natural groups (which may be families or subfamilies; Courtney in prep.). The begging call of young Cacatua cockatoos is a repetitive, harsh, straight, droning wheezing note which sometimes lapses into a clearer whistling tone. Each wheezing note varies in length between species in Cacatua, being shortest in the Galah (mean rate 60 notes per minute, as also in Nymphicus and Callocephalon), intermediate in the Pink Cockatoo Cacatua leadbeateri and in the corella complex (c. 45 and 30 notes per minute respectively), and longest in the Sulphur-crested Cockatoo (c. 14 calls per minute). The harsh, droning wheezing tone is immediately identifiable as Cacatua, and differs recognisably from the smooth, soft hissing of the Nymphicus hollandicus, and the strange, buzzing wheeze of the Gang-gang Cockatoo Callocephalonfimbriatum. Of the 'black' cockatoos, the Palm Cockatoo appears to have a note reminiscent of the Sulphur-crested Cockatoo. Within , those with yellow or white tails (C. funereus superspecies) emit a repetitive, harsh rasping sound, whereas those with red tails (C. banksii and C. lathami) utter a repetitive, brief, high-pitched squeak (described by Courtney 1986a,b and Saunders 1983) . For audio examples of these vocalisations, refer to Buckingham & Jackson (1988, 1989). Factor 2 seems unique to the Cacatua genus, except that a rudimentary trace of this may occur in the Palm Cockatoo. It is a brief pip vocalisation sandwiched in between each note of the begging call, and seems to be a breath-drawing noise. It is a distinctive idiosyncrasy of Cacatua, and though present in all Australian species observed it is most used by the Galah and the corella complex. This note was mentioned by Pidgeon (1981) but not assigned any name, therefore it is referred to here as the Breath-drawing 'Pip' Vocalisation (for audio examples, refer to Buckingham & Jackson 1988) . Factor 3 is also unique to the genus Cacatua. When begging for food the young of these cockatoos, including the Ga1ah , all slowly and extensively sway the head and body from side to side in a continuous fashion, except the Pink Cockatoo which in an aberrant way 'sways' by slowly rocking forwards and backwards in a bowing motion (pers. obs.). The young of all other cockatoo genera do not sway when begging, only when showing fear (Courtney 1974). Unwary and inexperienced observers of recently acquired young cockatoos must be careful not to confuse fear-induced swaying with true begging postures. · (4). Only Cacatua cockatoos have a wide, bare strip of skin surrounding the eye (periophthalmic ring) that also happens to be distinctively and permanently coloured (red, white or blue), and in some species heavily carunculated as well (Galah, Sulphur­ crested Cockatoo). All other genera of cockatoos have a plain blackish-brown, narrower strip of skin surrounding the eye, except males of the Calyptorhynchus funereus superspecies, and this changes colour for display, so is probably analogous not homologous with that of Cacatua. (5) . Cacatua cockatoos, including the Galah, are unique among parrots in alone possessing sexually dimorphic coloured irides, which are red (or of a diminishing red) in females and blackish brown in males. In all other parrots that have brilliantly coloured irides, these are brightest in males and used for display purposes (i .e. 'eye­ blazing' ) but occur in females also. The only exceptions are some of the hanging­ parrots Loriculus, and in these, the males have brilliant irides and the females brown ones (Forshaw 1978) . VOL. 15 (2) JUNE 1993 Taxonomic Position of Galah 63

This dimorphic iris colour reaches its zenith in the Galah and Pink Cockatoo. It is patchy in eastern Australian Sulphur-crested Cockatoos, in which many females seem to have blackish-brown irides like males. Some females have dark burgundy-red irides, and occasional females have the most brilliant fiery-red irides, far more brilliant than any Galah or Pink Cockatoo (pers. obs.). Presumably then, this species once had this feature but is now losing it. Low (1986) and Forshaw (1978) gave the following details: the Lesser Sulphur-crested Cockatoo C. sulphurea seems more uniform, with females having brownish-red irides and males brown (for illustration of female iris, see Low 1986). Irides are reddish brown in female and dark brown in male Blue-eyed Cockatoos C. ophthalmica. In the Umbrella Cockatoo C. alba the female iris is reddish brown and male dark brown. In the Salmon-crested Cockatoo C. moluccensis it would seem that there is no sexual dimorphism in iris colour (Forshaw 1978; R. Low in litt. 14 Jan. 1992). All Australian mainland corellas have dark brown irides in both male and female, but the following three island corellas exhibit sexual dimorphism. The males all have dark brown irides, but those of female Goffin's Cockatoo C. goffini are paler brown; in Ducorps' Cockatoo C. ducorpsii irides are reddish in females ; and in the Red-vented Cockatoo C. haematuropygia female irides are distinctly brownish red. All of this suggests that the ancestral Cacatua had red irides in the female, like the Galah and Pink Cockatoo, but there is now a tendency for this to be lost. Whatever the function of this red iris in the female was, it probably is of functional use now only in the Galah and Pink Cockatoo. When some members of a group possess a feature in common, whereas in others of the group the feature (e.g. red irides) is either rudimentary or absent, then it is a relict feature that is being lost, not gained. Such a feature can only be inherited through a gene from a single common ancestor - it is unlikely that members of a group would be independently evolving a common feature. Though apparently not recorded in the literature, Gang-gang Cockatoos are also sexually dimorphic in the irides, though in this species the iris of the male is blackish brown and that ofthe female is pale brown, better described as khaki. This dimorphism suggests a primitive link with Cacatua, but does not negate the uniqueness of their red irides. (6). All Cacatua cockatoos, including the Galah, have some body and head feathers that are white (Courtney 1974), hence the term 'white' cockatoos. The only other cockatoo to have feathers that are wholly white is the Cockatiel, and these are on the wing coverts, not head and body. (7) . All Cacatua cockatoos, including the Galah, have head, neck or throat feathers that have their fluffy downy bases coloured yellow or various shades of pink, except C. alba and possibly C. ophthalmica. Such contrasting coloured bases do not occur in any other cockatoo. This factor is strong and consistent in those species with pink, and weak and inconsistent in those with yellow. A difference in the head feathers exists between the Galah and the corellas. In the Galah, the basal extremity is white followed by extensive pink. In the corellas all of the basal half is pink, except in C. haematuropygia where it is yellow and pink. In both the Galah and the corellas, the terminal half is white. (8). All Cacatua cockatoos have plain feathering that is unbarred and untipped with another colour. All other species of cockatoo have feathers that are barred or tipped with another tone, at some stage in their life. This is self-evident in Nymphicus, Callocephalon and Calyptorhynchus; and Macgillivray (1914) recorded both tipping and barring in a juvenile Probosciger. (9). All Cacatua cockatoos have rectrices (main tail feathers) that are broadest at the tip and narrowest at the base, thus giving the feather a blunt, club-shaped appearance. This is perhaps least pronounced in the Galah, and most pronounced in the Sulphur- AUSTRALIAN 64 COURTNEY BIRD WATCHER crested Cockatoo, with the others somewhere in between. A slight tendency towards this shape seems to occur also in the Gang-gang Cockatoo, and not surprisingly in view of the dimorphic iris condition, which in combination suggests an early link in both genera. More surprising is this rectrix shape in the Palm Cockatoo (R. Schodde in !itt. 6 October 1992). Rectrix shape in the Cockatiel is the opposite to Cacatua, being long and pointed towards the tip. In black cockatoos Calyptorhynchus the rectrices are long and uniform in width, being neither clubbed nor pointed. (10). All members of Cacatua, except the Galah, have an extensive yellow or pink suffusion on the undersurface of the inner webs of the rectrices and remiges, whereas in the Galah, a pink suffusion is evident only on a small area of some of these feathers in some individuals. An analysis of the above ten 'definitive Cacatua characteristics' shows that the Pink Cockatoo has nine and lost one (sideways swaying begging posture); the three mainland species of corella (following Ford 1985) have nine and lost one (sexually dimorphic irides); the three island corellas presumably have ten out of ten; the Sulphur-crested Cockatoo superspecies comprising galerita and sulphurea has ten out of ten, with some individuals of galerita having a tendency to lose one (dimorphic irides); the related species ophthalmica and alba presumably have nine and lost one (coloured bases to feathers of throat and neck); inoluccensis is questionable and may have only nine out of ten (lacks dimorphic irides?); and the Galah has nine out of ten (the tenth factor is present but rudimentary, either it has been virtually lost or the species did not fully achieve the pink suffusion under wings and tail). Clearly, the Galah falls well within the core Cacatua assemblage.

Discussion and conclusions In wing shape, the Galah is at the end of a continuum from broad, rounded wings with short primaries and long secondaries in the Sulphur-crested Cockatoo, through to the corellas which have an intermediate wing shape approaching that of the Galah. Wing shape is presumably adaptive, related to the daily need for sustained flight over long distances: are probably the most mobile of the cockatoos, often (even daily) commuting many kilometres (e.g. Forsaw 1981, Rowley 1990; JC pers. obs.). The small, stout bill is probably a simple anatomical (adaptive) consequence of a powerful bill on a small cockatoo. Though Galahs do continuously beat their wings in flight and other Cacatua cockatoos have a habit of making frequent brief glides in their flight pattern, this is not absolute. Sulphur-crested Cockatoos and corellas flying long distances to and from a feeding site do not use the 'brief glide', but do so when landing is in sight, so presumably it is an intention movement or signal. Therefore, as gliding is not an unavoidable part of the flight pattern of Cacatua, as is, for example, undulation of flight in broad-tailed parrots, it is not a solid taxonomic character. Furthermore, Galahs do use the shallow, hesitant flight and brief glides in display flights (as do other 'white' cockatoos, pers. obs.). The claim, relating to behaviour, that Galahs may deviate from the traditional cockatoo direct ('under-the-wing') method of head-scratching because of an observation on a young (?) caged bird, has dubious value; Galahs (like other cockatoos) usually head-scratch by the direct method. In any case, Smith (1975) has shown that the head-scratching method is not a 'solid' taxonorni~: character: for example, unlike all other cockatoos, the Cockatiel scratches 'over the wing'; this does not mean that it is not a cockatoo. VOL. 15 (2) JUNE 1993 Taxonomic Position of Galah 65

As regards differences in colour of plumage, it must be pointed out that this is not a matter of real difference, but one of degree only. The grey of the Galah is not unique: it is now known that many juveniles of Cacatua species have some grey in their plumage (Courtney 1974, 1985). In addition to the Sulphur-crested Cockatoo and the corella complex, grey has now been observed in some juveniles of the Salmon­ crested Cockatoo as well (R. Low in !itt. 15 July 1987). To remove the Galah from Cacatua on presence of grey in adults, when grey is present in the common gene pool of Cacatua, would be an exercise in 'splitting hairs'. The completely rose-pink breast is certainly unusual. However, many Cacatua cockatoos do possess pink in their plumage, but not to such an extreme degree. Even bizarre colour differences are not necessarily indicative of a wide genetic gap, e.g. Weber's Lorikeet Trichoglossus haematodus weberi is completely green, the Ponape Lorikeet T. rubiginosus is completely red, and both are part of one genus; the Crimson Rosella Playercercus elegans elegans is deep red, whereas its alleged the Yellow Rosella P.e. jlaveolus is quite yellow. Holyoak (1970) came up with a valid difference, the total lack of yellow in the Galah, whereas all other species of Cacatua have at least some token yellow. However, it can be lost. Males of the western subspecies of the Pink Cockatoo C.Z. mollis are stated by Forshaw (1978) to have ' darker red with little or no yellow' (italics mine). There is no yellow elsewhere on the Pink Cockatoo. As for the taxonomic value of 'pink-downed nestlings', it is generally erroneously assumed that all Cacatua young have long, yellow natal down, whereas that of the Galah is pink, and thus 'unique' (e.g. Forshaw 1981, p. 92). However, nestlings of the Pink Cockatoo are clad in a minimal vestige of very short, off-white natal down (Courtney 1985 mistakenly used 'buffy-white' when 'beige-white' was intended). If one unchallenged member of Cacatua (the Pink Cockatoo) can have aberrant natal down, the Galah can too. With colour differences (amounting to retention of grey pigmentation in adults and intensification of pink) shown to be an unreliable indicator of phylogeny in the Galah, and the taxonomic value of 'pink-downed nestlings' shown to be questionable, the case of Schodde (1988) and Hornberger & Schodde (in prep.) must rest on cranial differences. It would be unethical of me to attempt to comment on the differences and their significance until such work is published in full, for it is their work and not mine. However, it can be said that Smith (1975, p. 33), in his classic review of the systematics of parrots, was cautious in accepting cranial features. He found marked differences in detail between species in large genera (e.g. Amazona), and conversely found confusing similarities between unrelated species of similar size, and concluded that skull morphology in isolation may be a misleading guide to systematics. There is a curious similarity in many respects between the highly aberrant Palm Cockatoo Probosciger and the genus Cacatua, that has apparently gone unrecognised. The juvenile begging call in the only recorded example of the Palm Cockatoo (Buckingham & Jackson 1988) seems closely similar to that of the Sulphur-crested Cockatoo, and also carries a hint of the Breath-drawing 'Pip' Vocalisation. Probosciger and Cacatua have club-shaped tail feathers. When angry or frightened Probosciger, Cacatua moluccensis and C. alba react in the same way, by stamping a foot on their · perch (Smith 1985). In addition, Schmutz & Prus (1987) pointed out that the karyotype of C. moluccensis possibly provides a link between Probosciger and other cockatoos. Therefore, the sharing of a common feature ('club-shaped' rectrices) by Probosciger and Cacatua may not be unusual and does not negate the taxonomic value of this feature, used in conjunction with other features. There are many differences between species in the genus Cacatua, and historically this has been accommodated by the use of subgenera (e.g. Anon. 1926, Peters 1937, AUSTRALIAN 66 COURTNEY BIRD WATCHER

Vane 1959, Lendon 1973). Those adopted by Lendon (1973) seem the most realistic and, with one modification (the merging of alba and moluccensis into the subgenus Cacatua), are outlined here. The members of subgenus Cacatua are distinguished by possession of blackish bills, exposed non-feathered ceres and long unhanded crests, and consist of galerita, sulphurea, ophthalmica, alba and moluccensis. Subgenus Lophochroa (Pink Cockatoo: leadbeateri) has the characteristics of pink and yellow banded crest, pink suffusion under wings and tail (moluccensis has yellow and pink, or orange, under tail), extremely short uncoloured natal down, cranial differences (R. Schodde in litt. 18 July 1990), forward swaying begging posture, and habit of maintaining huge nesting territories. Subgenus Eolophus (Galah: roseicapilla) is distinguished by colour scheme of grey (with white) in adult plumage and accentuated rose-pink undersurfaces, pink down in nestlings, cranial differences, lack of yellow and lack of brief glide in normal flight. The subgenus Ducorpsius (corellas: pastinator, sanguinea, tenuirostris, goffini, ducorpsii, haematuropygia) is recognised by the unique combination of yellow suffusion under wings and tail, with pink downy bases to feathers of head, neck or throat. The subgenera are locked together by various features shared in common: the elongated, recurved crest links subgenera Cacatua and Lophochroa; whitish bill with cere covered by small feathers links Lophochroa, Eolophus and Ducorpsius. Eolophus and Ducorpsius are further linked by their very short, rounded white crests with pink bases to the feathers, and Eolophus and Lophochroa are linked by the brilliant red irides of adult females. Finally, the subgenera Cacatua and Ducorpsius are linked by uniform cranial similarities (R. Schodde in litt. 18 July 1990). These four subgenera form the genus Cacatua, which in turn is distinguished by the collective possession of the 10 'definitive Cacatua characteristics' already discussed. In conclusion, if truly depicts phylogeny, then the possession of nine out of ten 'definitive Cacatua characteristics' by the Galah, with the tenth present in rudimentary fashion, when seven other species of Cacatua (out of a total of 13) also score only nine out often, seems to place the Galah squarely in Cacatua. To remove it from that genus on the strength of some cranial differences (legacies of proto-Cacatua, or related to the Galah's small size?), to the total disregard of nine similarities shared in common, would seem to be a negative move creating more problems than it solves, and is therefore unwarranted.

Acknowledgements Rosemary Low of Canary Islands supplied me with photographs and data proving the occurrence of grey in juvenile Salmon-crested Cockatoos. Julianne Courtney of , Brendan Lepschi of Canberra and Stephen Debus of Arrnidale sent me hard-to-obtain literature; Wayne Wilcox of Tenterfield supplied rectrices and remiges from his Gang-gang Cockatoos for comparison; Mervyn Goddard of Tenterfield, 'Sandy' and Judy Hunt of Tamworth, John Young of Ingham, and Neville and Enid Connors of Grafton, all assisted me with data on young cockatoos, and to all these people I am most grateful. I am especially grateful to Dr R. Schodde who has always responded to my numerous questions and freely discussed his own views, who read and commented on a draft of this paper, and examined a series of Palm Cockatoo skins to confirm rectrix shape. I am grateful too to Dr Les Christidis (Museum of Victoria) who examined specimens of Cacatua alba, C. ophthalmica and C. ducorpsii for feather base colour - and rectrix shape. Three referees commented helpfully on a draft. As taxonomy will always provide alternative views, some strongly held, I wish to state that the opinions expressed in this paper are mine alone, and not necessarily those of other people who have kindly assisted me in various ways.

References Adams, M., Haverstock, P.R. , Saunders, D.A., Schodde, R. & Smith, G.T. (1984), 'Biochemical systematics of the Australian cockatoos (Psittaciformes: )', Aust. J. Zoo!. 32, 363-377. Anon. (1913), Official Checklist of the of , Checklist Committee, Royal Australasian Ornithologists Union, . VOL. 15 (2) JUNE 1993 Taxonomic Position of Galah 67

Anon. (1926), Official Checklist of the Birds of Australia, Royal Australasian Ornithologists Union, Melbourne. Bonaparte, C.L.J.L. (1854), 'Tableau des perroquets. Monographie du genre Pisnus', Rev. Mag. Zoo/. (2) 6, 145-158 [original not seen]. Bucldngham, R. & Jackson, L. (Eds) (1988), A Field Guide to Australian Birdsong, Cassette 4, Sooty Tern to Superb Parrot, Bird Observers Club of Australia, Melbourne. --& --(1990), A Field Guide to Australian Birdsong, Cassette 5, Regent Parrot to Masked Owl, Bird Observers Club of Australia, Melbourne. Christidis, L., Schodde, R., Shaw, D.D. & Maynes, S.F. (1991), 'Relationships among the Australo­ Papuan parrots, lorikeets and cockatoos (Aves: Psittaciformes): protein evidence', Condor 93, 302-317. Condon, H.T. (1975), Checklist of the Birds of Australia: Non-passerines, Royal Australasian Ornithologists Union, Melbourne. Courtney, J. (1965), 'Down colouring of some Australian parrots', Emu 65, 148; also corrigenda, 317. -- (1974), 'Comments on the taxonomic position of the Cockatiel', Emu 74, 97-102 . - - (1985), 'Natal down and grey in the juvenile plumage of cockatoos Cacatua spp.', Aust. Bird Watcher 11, 94-95. --(1986a), 'Age-related colour changes and behaviour in the Northern Funereal Black-Cockatoo Calyptorhynchus June reus June reus', Aust. Bird Uiltcher 11, 137-145. -- (1986b), 'Plumage development and breeding biology of the Glossy Black-Cockatoo Calyptorhynchus lathami', Aust. Bird Uiltcher 11, 261-273. Ford, J. (1985), 'Species limits and phylogenetic relationships in corellas of the Cacatua pastinator complex', Emu 85, 163-180. Forshaw, J. (1963), 'The parrots of Australia: 5. The Galah', Avicult. Mag. 69, 160-169. -- (1969), Australian Parrots, 1st edn, Lansdowne Press, Melbourne. - - (1973), Parrots of the World, 1st edn, Lansdowne Press, Melbourne. -- (1978), Parrots of the World, 2nd edn, Lansdowne Editions, Melbourne. -- (1981), Australian Parrots, 2nd edn, Lansdowne Editions, Melbourne. -- (1989), Parrots of the World, 3rd edn, Lansdowne Editions, Melbourne. Gould, J. (1865), Handbook to the Birds of Australia, author, London. Holyoak, D.T. (1970), 'Structural characters supporting the recognition of the genus Eolophus for Cacatua roseicapilla', Emu 10, 200. Lendon, A.H. (1973), Neville W Cayley's Australian Parrots in Field and Aviary, Angus & Robertson, Sydney. Low, R. (1986), Parrots, their Care and Breeding, 2nd edn, Blandford Press, Poole. Macgillivray, W. (1914), 'Notes on some north Queensland birds', Emu 13, 132-186. Mathews, G.M. (1916), The Birds of Australia, vol. 6, Witherby, London. Peters, J. (1937), Checklist ofBirds ofthe World, Harvard Mus. Comp. Zoo!., Cambridge, Massachusetts. Pidgeon, R. (1981), 'Calls of the Galah Cacatua roseicapilla and some comparisons with four other species of Australian parrots', Emu 81, 158-168. Rowley, I. (1990), The Galah, Surrey Beatty, Sydney. Saunders, D.A. (1983), 'Vocal repertoire and individual voice recognition in the short-billed White­ tailed Black-Cockatoo Calyptorhynchusfu.nereus latirostris Carnaby', Aust. Wildt. Res. 10, 527-536. Schmutz, S.M. & Prus, S.E. (1987), 'A cytogenetic study of four species of cockatoos and amazon parrots', Genetica 74, 69-71 [original not seen]. Schodde, R. (1988), 'New subspecies of Australian birds', Canberra Bird Notes 13, 119-122. - - . & Tidemann, S.C. (Eds) (1986), Reader's Digest Complete Book ofAustralian Birds, 2nd edn, Reader's Digest Services, Sydney. Smith, G. A. (1975), 'Systematics of parrots', Ibis 111, 18-68. --(1985), 'The Palm Cockatoo (Probosciger aterrimus)', Magazine ofthe Parrot Society 19, 32-40. Vane, E.N.T. (1959), 'Some observations on the Cacatuinae- the cockatoos', Avicult. Mag. 65, 9-16.

Received 11 December 1991 Revised 1 February 1993 •