VOL. 17 (4) DECEMBER 1997 185

AUSTRALIAN BIRD WATCHER 1997, 17, 185-191

Age-Related Colour Changes and Behaviour in the Ground Parrot Pezoporus wallicus

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

Summary Three chicks of the Ground Parrot Pezoporus wallicus, from northern New South Wales, were hand-reared in 1977 as part of a larger project on Australian parrots. These juveniles began to acquire the red frontal band when aged 3 months 1 week, and this process was completed by 4 months. The pink bill and cere of chicks began to grey at 2 months, gradually darkening to the grey of adults at 6 months. Chicks had dark brown irides which gradually lightened to pale brownish white at 6 months. By 3 years of age, the two birds presumed to be males exhibited slight sexual dimorphism in having plain green unstreaked feathers on the throat/upper breast; in contrast, these feathers in females (and juveniles) had a black blotch in the centre. Males had plain pale blue feathers on the underside of the carpus (not examined in a presumed female). These feathers were also plain pale blue on two unsexed nestlings. Males performed a 'shoulder-squaring' courtship display typical of platycercine parrots, but did so on the ground. They also performed a vigorous 'body-bouncing' display while perched. The species is partial to water-bathing and sun-basking. Courtship-feeding was confirmed. The method of head-scratching is 'over the wing'. Males also had an unusual ritualised fighting method. Except for courtship-feeding, no physical contact between individual Ground Parrots was observed. The birds roosted apart at night, usually on the ground, but sometimes perched. All activity was diurnal.

Introduction Although the Ground Parrot Pezoporus wallicus is difficult to observe in the field because of its shy behaviour, cryptic plumage and preference for dense ground cover (Gosper 1995), its basic biology is now well known (e.g. Meredith et al. 1984; Jordan 1987, 1988; McFarland 1988, 1991a,b). However, many aspects of colour changes and behaviour from chick to adult have remained unrecorded because of the difficulty of observation in the field. This study, using hand-reared captive birds, attempts to redress these deficiencies. Lendon (1973) observed that data are non-existent on courtship-feeding, water-bathing, age of acquisition of red frontal band, and method of head-scratching. As much of this previously unknown information was obtained when observing the individuals in this study, the results are presented to supplement information on the life-history of the species.

Methods The three young Ground Parrots of this study originated from the north coast of New South Wales, and thus belonged to the nominate race wallicus of the eastern Australian mainland. When hand­ rearing began on 18 September 1977, the chicks' remiges (secondaries) were 10 mm long. On the evidence of Hodges (1961) they were estimated to be 12 days old. Rearing of an unrelated fourth young, estimated to be two days older than the other chicks, began on 3 October 1977, and a further two wild nestlings were subsequently examined. This study was the continuation of the project outlined in Courtney (1974), and was an extension of the study by Courtney (1997). Results

Colour The nestlings in this study (see photo in Low 1986) and those observed by Hodges (1961) had pink bills. Their bills began to darken at about 58 days old, and gradually became the grey of adults at six months old. Initially their ceres were also pink. This paled to creamy white as their beaks began to darken, then gradually became grey over the same period as the mandibles darkened. AUSTRALIAN 186 COURTNEY BIRD WATCHER

The nestlings had dark brown irides that gradually paled, becoming pale brown with underlying white, at six months of age. The flesh-coloured feet and legs of juveniles and adults were faintly tinged with grey, a feature previously noted by Serventy & Whittell (1962). This is a condition considered unusual in parrots (Smith 1975). The usual brown appearance oflegs (e.g. Forshaw 1981) seems to be an illusion created by dust and dirt, for their legs appear almost flesh-coloured after bathing in water. At about 100 days" old, all three young remaining (one of the original brood died) had acquired a small (c. 1-1.5 mm diameter) patch of red feathers immediately above the natural division in the centre of the cere. Previously, the feathers in this region were green and black. Twenty days later their red frontal bands appeared complete, having spread outwards from the centre. By three years of age, when they started performing courtship behaviour, two of the three Ground Parrots (thought to be males) differed by having the throat and upper breast plain green. The age of acquisition of the plain green feathers was not determined precisely. In contrast, the third individual (thought to be female) had the feathers of the throat and upper breast green with narrow black centres along the shafts, giving them a streaked appearance; this condition persisted until the bird died at about four years old. These feathers closely resembled those evident in a photograph by J. Gray (in DeJose 1989) of a presumed female brooding nestlings in the wild. A Ground Parrot incubating eggs (Evans Heac!, N.S.W.) that was killed and eaten on the nest by a Grass Owl Tyto capensis, leaving only the head and throat, also had green feathers with black shaft-streaking on the throat (pers. obs.). Two unsexed nestlings had black­ blotched throat/upper-breast feathers; the black was more pronounced than on the presumed adult females discussed above. In the two adult males, most feathers on the undersurface of the carpal joint were pale blue, along with a few scattered green feathers. This was discovered when one individual was observed making the typical platycercine 'shoulder-squaring' courtship display, which is thought to display the blue colour-patch beneath the carpus (e.g. Lendon 1973, Smith 1975). Two wild nestlings, subsequently examined, had similar plain pale blue feathering beneath the carpus. The feathering in this region was not recorded for the presumed adult female. Nestlings have remiges resembling those of adult Ground Parrots. The secondaries have two yellow spots, and sometimes a small third spot is present on the rear vane. The primaries have a single spot on the rear vane, corresponding to the 'wing-stripe' of most platycercines. In most primaries, and some secondaries, a pale triangular patch ('toothing') is present on the frontal vane (Schodde & Mason 1980). Some secondaries closest to the body have multiple 'toothing'.

Behaviour Unlike most other parrots, Ground Parrots can run at varying speeds, at least as quickly as gamebirds of similar size, and appear not to bound like many platycercine parrots do. When running at top speed around an aviary, their legs become a blur to the human eye. They readily climb aviary netting (contra Lendon 1973), grasping alternately with beak and feet, moving up or down at an angle, and descending tail­ first. They also climb into bushes and tangles of fine branches, perching competently. When large bunches of green seeding grass were placed in the aviary, the parrots usually clambered up onto the unstable mass, rather than standing on the ground to feed . When climbing about, their long claws appeared to act as extensions to the toes, helping to prevent their feet from falling through between the stems. Their long legs VOL. 17 (4) DECEMBER 1997 Morphology and Behaviour of Ground Parrot 187 enabled them to step up onto tussocks with minimal effort. Sometimes when feeding on the ground, they reached above their heads with one foot to pull down seeding grass within reach of the bill. They held entire seed-heads in the foot while eating, never single large seeds as other parrots often do. These parrots were ambidextrous, an unusual trait in parrots. Close observation showed that the foot chosen to pick up a fallen seed-head happened by chance: it was simply the foot not supporting the body weight at the time of nearest approach to the object. When the parrots were eating, their pupils suddenly contracted greatly when the tip of the bill approached within 1 em or so of the food item. This action appeared to be connected with close focusing of the eyes. Courtship-feeding was confirmed in the Ground Parrot when, at the age of almost three years, one presumed male was seen to make preliminary head-bobs, then regurgitate with gentle head-bobbing into the slightly up-turned beak of the presumed female. No food-soliciting call was uttered, in contrast with the behaviour of adult female Budgerigars Melopsittacus undulatus which vocalise like juveniles when food­ soliciting (Wyndham 1980). Ground Parrots drink unhurriedly by immersing the partly opened but immobile mandibles and rapidly pumping the contained tongue up and down. The head is lifted up and down from the water a number of times, but never tilted back like cockatoos. In comparison, Budgerigars drink in a different way by immersing the bill once only and rapidly opening and closing the mandibles, then flying off (pers. obs.). The Ground Parrots were observed water-bathing at least daily, during which they squatted deeply in the water, dunked the head and vigorously flapped the wings in similar fashion to rosellas Platycercus. The species also sun-basks, and is extraordinarily partial to and tolerant of solar radiant heat, more so than any other parrot encountered in this and related studies (Courtney 1997 and relevant references). The Ground Parrots were frequently observed lying stretched out on one side, with uppermost wing fully extended over the legs in typical platycercine posture, in high midday summer temperatures which caused stress to other parrots in aviaries nearby. Apart from gaping the bill and breathing rapidly (which probably acts as a heat­ exchange mechanism), they exhibited no signs of heat-distress. The Ground Parrot lifts the foot over the lowered wing to scratch the head, the method normally used by platycercines. Shortly before the age of three years (and a few days before courtship-feeding was observed), both males were observed in an activity interpreted as ritualised fighting. Several times, both males faced each other from a distance of at least 0.5 m, walked quickly towards each other, leaping into the air at each other when close, but bodily contact was avoided at the last moment when each bird rolled on its side with wings extended vertically, and glided past the other with bellies almost touching. Immediately on passing, they rolled back into normal horizontal flying posture, descended and landed. They then faced each other again, and repeated the performance. Eventually the slightly older bird ceased this activity and ran away, pursued briefly by the other bird. No further interaction between these two birds was observed, suggesting that aggression in this species is rather low-key. What may have been another aggressive display was directed at a human standing in the vicinity. In these instances a male sometimes ran rapidly towards a nearby person, all the while wagging the closed tail from side to side, but stopped short of contact. All observations suggested that the species is rather solitary; courtship-feeding was the only physical contact observed between these individuals. At night, all three always roosted well apart, usually on the ground but occasionally one used a low branch. No evidence was obtained of nocturnal activity, despite many observations AUSTRALIAN 188 COURTNEY BIRD WATCHER at night with a light, over a number of years (contra Webber 1948). The epigamic (courtship) display was commonly observed during September and October. The male stands upright and lifts the folded wings well away from the body at the 'shoulders' (carpus) while the tips of the wings remain touching the back. Presumably this is to display the soft sky-blue undersurface of the carpus, which in bright sunlight contrasts with the green of the body. The long tail is pressed firmly to the ground because of the upright body posture, and therefore cannot be fanned in the manner of most"platycercine parrots performing this 'shoulder-squaring' display. This posture is maintained for many seconds during which the bird may stand still, or walk slowly around in small circles, calling frequently with a series of short whistles usually described as 'tee tee tee'. Occasionally, a male perching on a branch vigorously thrusts the body up and down several times by bending and straightening its legs, while calling in a similar way. Vocalisations of nestlings have been described by Courtney ( 1997), and of adults by McFarland (1991a). The individuals of this study uttered a limited range of calls, of which the most frequently heard was the tee tee tee call. When recently fledged, the young warbled softly and constantly for long periods, in a manner similar to young Budgerigars and young Glossopsitta lorikeets. Males uttered a frog-like 'croak-click' call (for auditory example, refer to Buckingham & Jackson 1990), and occasionally a rapid succession of throaty 'clacking' noises. Two other calls were distinguished, but rarely used: when conditions were quiet and the birds undisturbed, one occasionally uttered an extraordinarily lengthy soft, thin whistle of unvarying pitch, which ended with about three brief whistles of the same pitch; conversely, when the birds were active, one uttered a brief 'double squeak'. It was not observed which of the three birds uttered these calls.

Discussion and conclusions All six nestlings observed had pink bills (see photographs of three of these birds in Low 1986). Some confusion has arisen regarding bill colouration in Ground Parrot nestlings and fledglings, since Lendon (1973) stated that young observed by him had yellow bills. However, these appear to be the same young observed by Hodges (1961), who clearly indicated (twice) that they had pink bills. The confusion has been compounded by Schodde & Mason (1980), who used the data ofLendon and not that of Hodges to predict that, because they are related, nestling Night Parrots Pezoporus (Geopsittacus) occidentalis would have yellow bills like Ground Parrots. Despite much data on young Ground Parrots in McFarland (1991a,b), there appears to be only one reference to pink bill colouration. Fledglings have brighter pink bills than 'adults' (McFarland 1991b) [sic; presumably a slip for 'nestlings', as adults have grey bills]. Photographs of young in the wild confirm that chicks ( 10 days old have bill and legs slightly paler pink than those of fledglings (D. McFarland in litt.). Pink is unusual, for all other young platycercine parrots observed (including the Budgerigar) (Courtney 1997) had yellow bills. The Ground Parrots in this study did not develop completely pale yellow irides (appearing almost white in bright sunlight) like some of the breeding birds in the study of McFarland (1991a,b), even though the older male survived to the age of 15 years. However, some wild breeding birds studied by McFarland had irides with brown flecking over palest yellow. It would appear that the hormonal stimulus associated with breeding may be necessary to complete the transition from pale brown irides, with underlying white, to pale yellow (D. McFarland in litt.). The streaking on the throat/upper breast of adult birds may vary, as revealed by a check of Queensland Museum specimens and photographs of incubating birds by VOL. 17 (4) DECEMBER 1997 Morphology and Behaviour of Ground Parrot 189

D. McFarland (in litt.). Of five adult male specimens, four lacked streaking and one (with 'white' irides) had streaking; a juvenile male (no red frons) was streaked. A juvenile female (just acquiring the red frons) was streaked; there were no confirmed adult female specimens, but of five unsexed adults, four lacked streaking and one was strea}ced. Of four presumed adult females, three in profile view had no streaking evident and one in front-on view had several blotched feathers although the streaking was less extensive than on the juvenile female specimen (from photos, per D. McFarland). It therefore appears that Ground Parrots, particularly males but perhaps also some females, tend to lose the breast-streaking with age. The above-mentioned museum specimens also revealed that all12 birds, regardless of age or gender, had blue under the carpus. The blue on the two juvenile birds seemed slightly less intense or extensive than on the adults (D. McFarland in litt.). The Ground Parrot is therefore not sexually dimorphic in this character, which also shows little age-related variation. Unlike the Ground Parrots observed, the unsexed Night Parrot specimen found by the roadside at Boulia, Queensland, in 1990 (Boles et al. 1994) appeared to have the carpal feathers greenish grey with black centres, much like other small feathers elsewhere on the body (pers. obs.). Investigation is warranted to ascertain whether the difference in the undersurface of the carpal joint is age- or gender-related in the Night Parrot, or is another difference between the Ground and Night Parrots (in addition to nature of cere, frontal band, iris colour, belly barring, tail length and shape, tarsus and claw length and shape, gait: cf. Forshaw 1978, 1981; Courtney 1997). If the latter, this would have implications regarding courtship display, for male Night Parrots would not 'shoulder-square' if there is no colour-patch to display. A behavioural difference, together with the morphological differences, may also have taxonomic implications. The merging of Geopsittacus with Pezoporus by Leeton et al. (1994) on unilateral molecular evidence may be premature, as they did not consider morphological or behavioural evidence. As noted by Courtney ( 1997), half of the genera comprising the platycercines are dark-eyed and 'shoulder-square' to show the blue under the carpus (the Ground Parrot in this group is uniquely pale-eyed), whereas many of the rest display their brilliantly coloured irides by 'eye-blazing' in courtship display. None has been reported to do both. This poses the question: Which behaviour came first? Of the platycercine parrots that are known to 'eye-blaze' in display (Melopsittacus, Cyanoramphus-Eunymphicus complex, Lathamus), all have traces of blue beneath the carpus in many individuals, with the Red-fronted Parakeet C. novaezelandiae having the most distinctive blue, more so than the Ground Parrot (pers. obs.; G.A. Smith in litt.), suggesting that their antecedents 'shoulder-squared'. Of the three 'eye-blazing' taxa above, all are disparate and do not represent a single lineage within the group (Christidis et al. 1991). This suggests that the most primitive true platycercines both ' shoulder-squared' and 'eye­ blazed'. As only platycercines and perhaps the Asian ringnecks Psittacula 'shoulder­ square' (Smith 1975, 1979) and many of the world's parrots 'eye-blaze', this in turn suggests that the earliest platycercines evolved from 'eye-blazing' stock which then developed 'shoulder-squaring' as well. Most platycercine genera have since discarded one of these displays, and at least one has discarded both (e.g. Red-capped Parrot Purpureicephalus spurius, Courtney 1997). If the species of any platycercine genus perform both displays, these will most likely be the tiger-parrots Psittacella which have blue beneath the carpus and brilliant irides. Psittacula may do so as well, but has yellow beneath the carpus (see Smith 1979, p. 108). The 'eye-blazing' display is arresting for it involves extreme contraction of the pupils to show the brilliantly coloured irides, e.g. see this depicted for the Princess AUSTRALIAN 190 COURTNEY BIRD WATCHER

Parrot Polytelis alexandrae in Groen (1966). Normally, only bright light contracts the pupil of the eye. The way in which the Ground Parrots and Budgerigars of this study contracted the pupils when reaching for, and close to, a seed, suggests how parrots can contract their pupils at will in courtship displays: 'eye-blazing' is probably achieved by throwing the eyes into 'close focus' mode. The remiges of Ground Parrots (and presumably of Night Parrots) appear to be unique in having two clearly marked pale spots on the secondaries, with a trace of a third on some, combined with single spots only on the primaries. As more than one pale spot should be regarded as barring, the Ground Parrot represents a condition intermediate between wing-barring and the more usual wing-stripe (ofplatycercines). Of the world's parrots (other than the above two), apparently only four other species have wing-barring formed by pale spotting. These are the Kakapo Strigops hohroptilus, Kea Nestor notabilis, and females of the Cockatiel Nymphicus hollandicus and Gang­ gang Cockatoo Callocephalon fimbriatum: all Australasian species of diverse lineages, but perhaps reflecting a common origin. Most aspects of behaviour observed in the Ground Parrot are consistent with what one might expect in a 'primitive', cryptic ground-dwelling platycercine that lives in exposed treeless areas. Its climbing ability and foraging behaviour, as observed in this study, are also consistent with Gosper' s (1995) subsequent observations of wild Ground Parrots feeding in shrubs, contrary to some earlier perceptions that the species is entirely terrestrial. Scepticism over the Parrot's climbing ability (e.g. Meredith et al. 1984) is therefore unwarranted, and there is no reason to doubt Favaloro's observation (in Forshaw 1981).

Acknowledgements I thank Mervyn Goddard and Jack Crisp for their knowledge, freely imparted. The original draft of this paper was kindly reviewed by Drs R. Schodde and G.A. Smith, who made many helpful suggestions. Dr Hugh Ford, then editor of Emu, offered helpful advice. Dr David McFarland reviewed the final draft, provided additional information, and kindly checked and reported on the Queensland Museum specimens and his photographs, promptly at short notice. I also thank Stephen Debus, John Peter and a referee for editing the final draft. Author's note This paper was initially submitted to Emu in 1981. A referee for that journal requested severe reduction of the paper and, as this was impractical, the paper was withdrawn. Some of the data have been moved to a companion paperc(Courtney 1997), and some of the original content has become redundant. For example, a prediction that the tiger-parrots Psittacella would be shown to be New Guinea platycercines, because they have barred plumage and blue beneath the carpus like Ground Parrots, has now proved correct (Christidis et a!. 1991). References Boles, W.E., Longmore, N.W. & Thompson, M.C. (1994), 'A recent specimen of the Night Parrot Geopsittacus occidentalis', Emu 94, 37-40. Buckingham, R. & Jackson, L. (Eds) (1990), A Field Guide to Australian Bird Song, 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. Courtney, J. (1974), 'Comments on the taxonomic position of the Cockatiel', Emu 74, 97-102; also corrigenda Emu 74, 346. -- (1997) , 'The juvenile food-begging calls and associated aspects in the Australian "broad- tailed" (platycercine) parrots', Aust. Bird Watcher 17, 169-184. DeJose, J. (1989), Australian Coastal Birds in Colour, Treasure Press Australia, Melbourne. Forshaw, J.M. (1978) , Parrots of the World, 2nd edn, Lansdowne, Melbourne. -- (1981), Australian Parrots, 2nd edn, Lansdowne, Melbourne. Gosper, D.G. (1995) , 'Notes on the activities of Ground Parrots in northern New South Wales', Aust. Birds 28, 57-64. VOL. 17 (4) DECEMBER 1997 Morphology and Behaviour of Ground Parrot 191

Groen, H.D. (1966), Australian Parakeets: Their Maintenance and Breeding in Europe, author, Haren. Hodges, M. (1961), 'Nesting of the Ground Parrot', Emu 61, 218-221. Jordan, R. (1987), 'The Ground Parrot in Barren Grounds Nature Reserve', in Jordan, R. & Jordan, P. (Eds), Barren Grounds Bird Observatory Report 1984-86, 19-23, Royal Australasian Ornithologists Union Repon 21. --(1988), 'The use of mist nets and radiotelemetry in the study of the Ground Parrot Pezoporus wallicus in Barren Grounds Nature Reserve, New South Wales' , Corella 12, 18-21. Leeton, P.R.J., Christidis, L., Westerman, M. & Boles, W.E. (1994), 'Molecular phylogenetic affinities of the Night Parrot (Geopsittacus occidentalis) and the Ground Parrot (Pezoporus wallicus)' , Auk 111 , 833-843. 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. McFarland, D.C. (1988) 'Geographical variation in the clutch size and breeding season of the Ground Parrot Pezoporus wallicus' , Aust. Bird Watcher 12, 247-250. --(1991a), 'The biology of the Ground Parrot, Pezoporus wallicus, in Queensland: I. Microhabitat use, activity cycle and diet; II. Spacing, calling and breeding behaviour; III. Distribution and abundance', Wildlife Research 18, 169-184; 185-197; 199-213. - - (1991b), 'Flush behaviour, catchability and morphometries of the Ground Parrot in south­ eastern Queensland', Corella 15, 143- 149. Meredith, C.W., Gilmore, A.M. & Isles, A.C. (1984), 'The Ground Parrot (Pezoporus wallicus Kerr) in south-eastern Australia: a fire-adapted species?', Aust. J. Ecol. 9, 367-380. Schodde, R. & Mason, I.J. (1980), Nocturnal Birds of Australia, Lansdowne, Melbourne. Serventy, D.L. & Whittell, H.M. (1962), Birds of Western Australia, Paterson Brokensha, Perth. Smith, G.A. (1975), 'Systematics of parrots', Ibis 117, 18-68. -- (1979), Lovebirds and .Related Parrots, Inkata Press, Melbourne. Webber, L.C. (1948), 'The Ground Parrot in habitat and captivity', Avicult. Mag. 54, 41-45. Wyndham, E. (1980), 'Diurnal cycle, behaviour and social organization of the Budgerigar Melopsittacus undulatus' , Emu 80, 25- 33. Received 4 August 1997 •