VOL. 11 (4) DECEMBER 1985 103

AUSTRALIAN WATCHER 1985, 11, 103-113

Parental Care and Investment in the Tooth-billed Scenopoeetes dentirostris (Ptilonorhynchidae)

By C.B. FRITH and D.W. FRITH, 'Prionodura', Paluma via Townsville, Qld 4816

Summary The known southern distributional limit of the Tooth-billed Bowerbird Scenopoeetes dentirostris is extended from Paluma (19°00'S, 146°l3'E) to Mt Elliot(l9°30'S, 146°57'E) near Townsville, Queensland. Records of the rarely found nest of Scenopoeetes, clutch size, egg weight, egg-laying and nestling periods are summarised. Systematic observations over 45 hours at three nests strongly suggest, but do not conclusively prove, uniparentalism presumably by females. Data for a single-nestling brood at one nest are compared with similar data for the uniparental Prionodura newtoniana and monogamous biparental Spotted melanotis, which provide further evidence in support of uniparentalism in Scenopoeetes. Meagre nestling diet information is summarised. Parental care and behavioural records are reviewed and previous erroneous and confusing reports discussed. •

Introduction The Tooth-billed Bowerbird* Scenopoeetes dentirostris is one of the least known of the 18 bowerbird species and is certainly less known than the other eight species in Australia. It occurs in upland rainforests between c. 600 and 1400 m above sea level from Mt Amos (15°42'S, 145°18'£) southward to Saddle Mountain on Mt Elliot (l9°30'S, 146°57'£) just south of Townsville, Queensland, where Dr George Heinsohn (pers. comm.) was attracted to an active court by typical male vocalisations on 13 November 1980. This is an extension of the previously known southern limit of this bird's range of 55 km due south or 90 km to the south-east from the previously recorded location of Paluma or Mt Spec (Storr 1973, Griffin 1974).

The Tooth-bill is an atypical bowerbird in being a very cryptically plumaged, sexually monomorphic rainforest dweller long thought to breed monogamously (North 1904, Jackson 1909, Marshalll954, 1964, Chaffer 1984) but which is now considered a species in which males are promiscuous and females uniparental (Gilliard 1969, Schodde 1976, Donaghey et al. 1985). Both sexes have conspicuous serrations on the mandible edges, which are used in eating foliage (Lavery & Grimes 1974, Frith & Frith 1979), hence the common name. Males do not construct bowers, as do males of other polygamous bowerbird species, but clear a court area of rainforest-floor leaf litter and place selected leaves paler side uppermost on to the clearing as decorations. At their courts males are spectacularly vocal, but are very wary and quickly retire to higher forest foliage if approached without great care.

*Tooth-billed CatbirdAiluroedus dentirostris in the Interim List of Australian , 1975. AUSTRALIAN 104 FRITH & FRITH BIRD WATCHER

Fema"te Tooth-billed Bowerbird biology is unknowl} save some anecdotal, misleading and confusing accounts in early oologicalliterature (see below). It is assumed that females are attracted to courts where they assess the quality of male vocalisations, displays, courts and decorations and perhaps male attendance levels (time investments) before soliciting a selected male. Females apparently incubate eggs and rear young unaided (i.e. without male assistance).

The nesting season, clutch size and brood size George Sharpe (Anon 1909) collected a nest and two eggs on 7 November 1908. Jackson (1909) found nests with eggs between 8 and 27 December: three clutches of two, and one of a single egg incubated for about 5 days which suggested a completed clutch. He also found two fertilised eggs in each of two females that he shot at male courts. Moreover, he found four additional nests containing one nestling between 5 (not 10 as cited by Marshall 1954 and repeated by Cooper & Forshaw 1976) and 26 December. The estimated age of one of these nestlings was 3 to 4 days on 5 December and another was 'rather well feathered' on 19 December. We add to this our nests: two with a clutch of two, and one nest with a single nestling (see below). The clutch of eggs collected by Sharpe on 7 November and one we found on 21 November appear to be the earliest recorded egg-laying dates for Scenopoeetes. Warham's (1962) very recently fledged nestling provides an approximate latest known fledging date of 22 January. Beruldsen (1980), however, gave the 'nesting season' as October to December and Schodde (1976) stated that 'nesting' occurs from September to January which is unlikely as males do not commence court clearing in any significant way . until September (pers. obs., in prep).

Parental care - the historical background Male Tooth-bills often appear the most conspicuous and numerous in their highland rainforest range during the summer, and yet remarkably very few nests have been recorded. A nest found by Mr G. Sharpe on 7 November 1908 (Jackson 1909, p. 265) appears to be the first record. Sharpe met S.W. Jackson in the Evelyn Scrubs and gave the latter hints on locating Scenopoeetes nests. Jackson was on a major three-month search for nests and eggs of highland rainforest birds but particularly for those of the Tooth-billed Bowerbird. He eventually located nine nests, by methodically sending aboriginal climbers up vine-covered forest trees, or by observing the movements of birds. None of these nests were visible from the ground, being small, sparse cup structures of fine tendrils placed in high, dense vine tangles. Jackson (1909) has published excellent photographs of nests and eggs, and of a nest containing a nestling. A note by W.S. Day (in North 1904, p. 70) states 'At the end of June they [Tooth-bills] begin to mate, and go about in pairs only' but this is contrary to our experience and that of others (Lavery & Grimes 1974) and is without foundation. Often, Jackson referred to 'Tooth-bills' or a 'pair' of birds being observed in order to locate a nest, or becoming excited when a nest was approached; or VOL. 11 (4) DECEMBER 1985 Tooth-billed Bowerbird: Parental Care & Investment 105

First published photograph of an incubating, presumed female Tooth-billed Bowerbird Scenopoeetes dentirostris, Paloma (north Queensland), December 1984 Plate 28 Photo: C. & D. Frith even to watching a fledged young being fed 'by the parents'. Moreover, he stated (1909, p. 276) that the 'pair' at a nest containing two eggs on 8 December involved a female that had maintained a court prior to nesting and a male that maintained his court until at least 13 December. His reference to male Tooth-bills taking any part in nesting can, we feel, be discounted as he was misled by the contemporary assumption that the Tooth-bill was a monogamously breeding bird (North 1904, p. 70) and therefore misinterpreted what he saw, or thought he saw. Our observations and those of others clearly suggest uniparentalism in Scenopoeetes whilst other statements by Jackson clearly indicate his confusion on this point. On several occasions Jackson noted only the one Tooth-bill at a nest He also specifically noted that Tooth­ bills 'sit close' on eggs, permitting a man to approach within a few metres. Such behaviour is also typical of sitting uniparental female Golden Prionodura newtoniana and Satin Bowerbirds Ptilonorhynchus violaceus (pers. obs.), but is far less so of sitting monogamous female Spotted Ailuroedus melanotis which quit the nest whilst an approaching human is further away relative to the close approach that the above uniparental females will permit (pers. obs.). Jackson's (1909, p. 256) first personal observation of the species involved 'a pair' of birds 'evidently conducting a primitive courtship ... rubbing their bills together'. We have seen similar activity on several occasions, involving two, three or four birds, but these instances appeared more likely to be aggressive encounters at a feeding tree. This initial observation of Jackson's may, however, have given him a lasting wrong impression. AUSTRALIAN 106 FRITH & FRITH BIRD WATCHER

Also indicative of Jackson's predisposition to the nption that both sexes of Scenopoeetes share nesting duties is his reference t<{'long-watched pairs of rifle birds' (Victoria's Riflebird Ptiloris victoriae) a(lnests. His error in this respect was not unique, as (promiscuous) bowerbirds and birds of paradise were widely thought to nest in pairs and were therefore 'seen' to do so by the biased observer. Foster (in Campbell 1901, p. 68) recorded both female and male Paradise Riflebirds Ptiloris paradiseus nest building. Hislop (in North 1904, p. 28) reported a 'pair' of the latter species driving a Blaclc Butcherbird Cracticus quoyi 'from the neighbourhood oftheirnest'. Significantly, however, all three references to riflebirds actually seen sitting on nests in Campbell (1901) involve female-plumaged birds only, and clearly the aforementioned records of apparent 'pairs' obviously involved a nest-building or nest­ defending female whose scolds had temporarily attracted the attention of a male. Our experience is that the scolding distress calls of a nesting female uniparental bowerbird (Prionodura, Ptilonorhynchus, Scenopoeetes) often quickly attract conspecifics which may join in the scolding. Whilst direct evidence ofuniparentalism in Ptiloris spp. is lacking (LeCroy 1981), members of this are invariably considered to be promiscuous in males and uniparental in females (Gilliard 1969, Cooper & Forshaw 1977, LeCroy 1981, Beehler 1983, Beehler & Pruett-lones 1983). Most regrettably Chaffer (1984) has, without any justification, repeated the assumption that male Tooth-bills assist not only in the· raising of young, but also in nest building. The recorded Tooth-bill clutch of only one or two eggs (Jackson 1909, Anon 1909; pers. obs.) and the apparently not uncommon brood of a single nestling (Jackson 1909; pers. obs.) indicate a small clutch size (x = 1.50, N = 14). The mean clutch size of monogamous catbirds is 2.12 for the Ailuroedus crassirostris (N = 17: Donaghey 1981) and 2.03 for the (N = 66: pers. obs.); that for the polygamous 1.97 (N = 30: Donaghey 1981) and Golden Bowerbird 1.70 (N = 20: pers. obs.). The low mean clutch size for Scenopoeetes may be due to us including the four single-nestling broods found by Jackson (1909) which may not have in fact been the result of single-egg clutches but which we included due to the lack of better data. Warham (1962) discovered a very newly fledged Tooth-bill on 22 January, and upon handling it only a single adult scolded him and performed a distraction display on the ground. Sharpe is reported to have collected his Scenopoeetes and Prionodura nests and eggs 'after waiting near the nest for over an hour and flushing the females from them several times' (Anon 1909). In one instance Jackson (1909) did specifically refer to only one disturbed parent at a nest.

Results and discussion On 1 August 1978 we commenced field studies on upland rainforest­ dwelling bowerbirds at a study site near Paluma (19°00'S, 146°13'E) c. 875 m above sea level approximately 70 km north-west of Townsville, Queensland, where the Tooth-billed Bowerbird is common. During the subsequent four bowerbird breeding seasons (September to March) we located only one occupied Tooth-bill nest, whilst finding numerous old and occupied nests of the Spotted Catbird, Golden Bowerbird and Satin Bowerbird. This lack of success was doubtless due to the sparse construction and well-concealed, VOL. 11 (4) DECEMBER 1985 Tooth-billed Bowerbird: Parental Care & Investment 107

typically high location of Tooth-bill nests and our lack of experience and 'search image' of them. At 0920 h on 9 November 1978 CBF saw a Tooth-billed Bowerbird snap off a fine twig c. 150 mm long and fly directly into the forest with it, presumably to build a nest. At 1215 h on 13 October 1979 CBF saw a Tooth-bill with a stick in its bill fly into a lawyer vine Calamus sp. tangle about 15 m high, and leave without the stick. On 20 December 1981 a Tooth-bill was seen flying into a dense inacessible vine tangle around a tree trunk about 22 m high, and was seen to leave and return over several days in a manner consistent with the behaviour of a lone incubating bird. On 23 December 1981 a Spotted Catbird was seen to hop to the rim of this nest, peer into it and depart. Subsequent watches indicated that this nest was deserted and, as catbirds Ailuroedus spp. are tenacious nest predators (Donaghey 1981; pers. obs.), the visiting catbird may have been previously responsible. On 21 November 1983 a Tooth-bill nest 12 m high in a fork in the crown of a forest-edge tree had a bird sitting on two eggs, but this nest was empty and deserted on 27 January 1984. On 21 November 1983 a<1other nest (Table 1, nest 1) was found 8 m high in a vine tangle suspended from branches of a forest-edge tree. It contained two eggs measuring 41.6 x 28.2 and 40.4 x 28.7 mm and both weighing exactly 16.3 g, this being the first weight taken for Scenopoeetes eggs. As no figure is available for the fresh egg weight of Scenopoeetes it is worth calculating it from the egg measurements as we have weights of the eggs seven days prior to their hatching. Fresh egg weight as a proportion of female body weight provides an important measure of the female's investment in egg formation (Trivers 1972). Tooth-billed Bowerbirds' eggs are essentially prolate ellipse in shape (Preston 1974), the volume of which can be derived by V = rr/6 x length x breadth 2 • Assuming a specific gravity of 1.05 glee for egg contents (Berghold 1929), the fresh weights of the eggs of this clutch were 18.2 and 18.3 g respectively. Unfortunately we have caught only one probable female Tooth-bill (showing a trace of a brood patch) on 6 December 1983, and it weighed 148.5 g. The calculated mean fresh egg weight of 18.25 g represents 12.3% of this individual's weight at that time. The mean body weight of ten other unsexed Tooth-bills, possibly predominantly males, caught between 5 and 18 December was 157.5 g and the derived fresh egg weight of 18.25 g represents a proportionate egg weight of 11.6%. Both these proportionate egg-weight figures fall within the similarly calculated ones of 11.6 to 12.6 % for the monogamous Green Catbird, but are higher than 10.2% for the uniparental Satin Bowerbird Ptilonorhynchus v. violaceus (Donaghey 1981, who gave a mean clutch size of 2.12 and 1.97 for the two species respectively). The proportionate fresh egg weight in relation to body weight in these bowerbirds is thus rather high for of their body weight (Lack 1968, p. 184, Donaghey 1981 , p. 79). The two eggs of nest 1 hatched sometime between 1000 h on 27 and 1300 h on 28 November 1983 and the young were absent, presumed preyed upon, on 1 December. Five hours were spent watching the incubating bird (presumed female) at this nest and 4.5 hours watching her care for nestlings during their first and second day of life (Table 1). AUSTRALIAN 108 FRITH & FRITH BIRD WATCHER

On 22 November 1983 we located nest 2 (Table 1) by seeing a female approach it and sit, apparently to incubate. The nest was 17 m high in a tree fork well concealed on three sides by lawyer vine Calamus australis foliage. Watches at this inaccessible nest were made almost daily from 27 November, when it contained a nestling estimated to be three days old, to 15 December 1983 inclusive. On 25 November 1984 a nest 9.8 m high in a suspended vine tangle was found to contain a single egg being incubated by a Tooth-bill. This egg was not subsequently added to over the next few days, but the nest could not be studied further.

Watches at nests 1 and 2 were made from a partly con~ealed position near the edge of an unsealed road c. 20 and 30 m from the nest trees, using tripod­ clamped 8 x 35 mm field glass·es focused on the nest. Both parent and nestling birds could be clearly seen and food items in their bills sometimes identified as fruit or . All. activities were timed by digital stop-watch and recorded immediately. Observations over approximately 45 hours at three nests (including the December 1981 nest) leave us in no doubt that one parent only was involved in all activity at each nest. Whilst no .birds were marked, their periods of presence and absence and their extra-nest movements left all four observers (see acknowledgements) in no doubt that one parent was involved. For example the female at nest 2 could often be seen to leave it and forage on fruiting trees very close to the observer before returning to the nest to feed the young. These observations together with what is known of the nesting biology of other polygamous bowerbird species (Gilliard 1969, Cooper & Forshaw 1976, Donaghey 1981) and our studies of male Tooth-billed Bowerbird behaviour through the breeding season (pers. obs. and in prep.) strongly suggest that female Tooth-bills are uniparental.

Female attentiveness during incubation A 140-minute watch that began at 1023 h when the two eggs were two days prior to hatching and a 160-minute watch that began at 0736 the day prior to hatching, were made at nest 1 on 26 and 27 November 1983 respectively. The percentage of observation time the female spent incubating was 63.1 (2 bouts) and 74.8 (3 bouts) (x = 69%) and the number of incubation bouts 0.9 and 1.2 per hour respectively. Incubation bouts ranged from 26 min 17 sec to 58 min 58 sec (x = 40 min 49 sec).

Brooding, feeding and maintenance of nestlings Table 1 summarises time-budgeted observations at two Tooth-bill nests over a composite (very predominantly single-nestling brood) nestling period. Similar comparative data are also presented for one-nestling broods of the uniparental Golden Bowerbird and biparental Spotted Catbird for the same location, habitat and time of year. These data are not adequate to take account of variables such as time of day, age of nestling(s), quality of meals, individual variation in parent behaviour or weather. Certain striking differences in figures for brooding and nest attentiveness are, however, apparent between the two uniparental species and the biparental catbird. Female Spotted Catbirds (males do not brood young) spent 50% of VOL. 11 (4) DECEMBER 1985 Tooth-billed Bowerbird: Parental Care & Investment 109 observation time brooding compared with 30 and 26% in the Tooth-bill and Golden Bowerbird respectively. These figures for uniparental Scenopoeetes and Prionodura are not significantly different (Mann-Whitney U = 105, n1 = 17, n2 = 11, p > 0.05) but are significant between Scenopoeetes and biparental Ailuroedus (Mann-Whitney U =50, n1 = 17, n2 = 10, p < 0.05); and between Prionodura andAiluroedus (Mann-Whitney U = 27, n1 = 11, n2 = 10, p < 0.05). For the purpose of these comparative statistical tests, and those below, the figures for Scenopoeetes nest 1 are omitted from the samples so that all are for single-nestling broods (for all three species). Female Spotted Catbirds spent almost twice as much time brooding per hour as did the uniparental females {Table 1), and a Mann-Whitney U Test applied to these means results in the same significance levels as above. Whilst the mean number of brooding bouts per hour are almost identical in the three species those of Ailuroedus were much longer (Table 1). The percentage of the total watch that parents spend at the nest [including brooding, feeding or perched on the nest rim preening, peering at or eating faeces of nestling{s)) was very significantly different between the uniparental and biparental species. Thus Scenopoeetes v. Ailuroedus Mann-Whitney U = 43, n1 = 17, n2 = 10, p < 0.025 and Prionodura v. Ailuroedus Mann-Whitney U = 21, n1 = 11, n2 = 10, p < O.ol, as is to be expected in view of ma1eAiluroedus participation in feeding young. No significant difference between uniparental Prionodura and Scenopoeetes (Mann-Whitney U = 93, n1 = 11 , n2 = 17, p > 0.05), however, supports the assumption that Scenopoeetes is uniparental. Donaghey (1981) presented similar data to those in Table 1 for the Green Catbird and Satin Bowerbird Ptilonorhynchus v. violaceus in sub-tropical rainforest and woodland in north-east New South Wales. His data are, however, for 238.8 and 182.2 hours of observation respectively over entire nestling periods at nests with several young within. His figures for percentage of time spent brooding by female Green Catbirds and Satin Bowerbirds are 31.0 and 5.9 respectively. Our data are far too few and different to compare with those of Donaghey, but the apparent gross differences may reflect greater abundance and/or density of foods in rainforests within the tropics, or differences in nestling diet, as would certainly appear to be the case in Ptilonorhynchus in which the nestling diet is 95% insects (Donaghey 198l). We learnt little about nestling diet due to distances between nests and observer. From 28 November to 1 December the nest 2 female was seen feeding her young (c. 4-7 days old) rather fluid meals, masticating them between her mandibles, presumably fruit pericarp or soft . On 28 and 30 November (young c. 4 and 6 days old respectively) she offered relatively large black fruits but they were not taken and so she swallowed them herself. On 2 December (young c. 9 days old) a black fruit was offered on two separate occasions and the second time the nestling managed to swallow it. One orange fruit was fed on 3 December (young c. 10 days old) and black fruits on 6 to 13 December inclusive (c. 13 to 20 days old). Many similar meals could not be identified, the female often arriving with mandibles closed or only slightly ajar. On 10 December the female chased and caught a flying insect, and on 15 December she fed the nestling an insect and then sallied for another and took it to the nestling. On three occasions she foraged on fruits of a tree only 40 m from the nest tree before returning to feed the young several AUSTRALIAN 110 FRITH & FRITH BIRD WATCHER

Table 1 Duration of parental activities at nests of the Tooth-billed Bowerbird Scenopoeetes

Nest' Age of' Date Time watch No. minutes %watch Brooding bouts no. young: days commenced per watch 9spent per hour brooding

SCENOPOEETES 1 1 28/11 13:51 150 53.1 3.6 1 2 29/11 14:33 120 35.6 3.0 2 3 27/11 08:00 120 52.6 2.0 2 4 28/11 14:08 120 42.6 2.0 2 5 29/11 14:27 120 46.6 2.0 2 6 30/11 07:23 260 39.3 2.1 2 7 1/12 09:58 120 52.2 2.0 2 8 2/12 12:09 120 14.5 0.5 2 9 2/12 15:26 60 9.1 1.0 2 10 3/12 07 :46 60 2 11 4/12 08:12 60 13.4 2.0 2 12 5/12 10:00 60 19.6 1.0 2 13 6/12 08:45 120 35.1 1.5 2 14 7/12 05:50 180 33.7 1.0 2 16 9/12 14:30 195 39.5 1.2 2 17 10/12 07:30 120 18.2 1.0 2 18 11/12 07:00 135 29.1 1.8 2 20 13/12 07:30 120 37.9 1.5 2 21 14/12 07:30 120 1.1 0.5 2360 30.2 1.6 PRIONODURA 4 6 27/12 07:45 120 46.7 2.5 4 7 28/12 07:10 120 43.9 2.5 4 8 29/12 10:30 120 52.8 2.0 4 9 30/12 09:00 120 36.2 2.5 4 11 1/1 10:20 120 45.5 3.0 4 12 2/1 08:15 120 26.3 2.0 4 13 3/1 06:55 120 35.5 2.0 4 16 6/1 10:00 120 0 4 18 8/1 14:30 120 0. 4 19 9/1 09:15 120 0 4 20 10/1 07:00 120 0

1320 26.1 1.5 AILUROEDUS 20 3 14/11 12:15 60 77.4 1.0 9 4 26/11 08:10 120 61.1 2.0 20 4 15/11 14:00 120 80.2 2.0 20 5 16/11 07:32 120 84.1 2.0 9 8 30/11 06:10 120 68.0 3.0 14 9 29/11 07:40 120 61.3 3.0 13 15 7/12 07:05 120 67.4 2.0 13 16 8/12 12:00 120 0 8 18 7/12 15:30 120 0 8 21 10/11 09:00 120 0 1140 50.0 1.5

'All nests contained a single nestling except Scenopoeetes nest 1 which contained a brood of two. Note that the figures for Scenopoeetes nest 1 are excluded from statistical tests in the text

2Age of nestling Scenopoeetes in nest 2 estimated from appearance when first seen, and fledging date assuming a similar nestling period toAiluroedus spp. Donaghey (1981) gave 21 VOL. 11 (4) DECEMBER 1985 Tooth-billed Bowerbird: Parental Care & Investment 111

dentirostris, Golden Bowerbird Prionodura newtoniana and Spotted CatbirdAiluroedus melanotis

x brooding x brooding x ad. nest3 % watch xfeeding xfeeding % of totaP bout time: per hour: visits per ad. feeding visits per bout time: watch parent(s) min/sec min/sec hour young hour sec at nest CENOPOEETES 8:53 31 :58 6.8 1.5 3.2 17 54.5 7:08 21:23 7 13.7 4.0 123 49.3 15:46 31:33 4 5.2 2.0 93 57.7 12:48 25:35 5 4.9 2.0 59 47.5 9:20 28:00 6 3.9 3.0 47 50.6 11:42 23:37 4.8 4.8 2.8 63 44.1 15:40 31:20 4 4.6 2.0 83 56.8 17:23 8:42 4.5 6.4 4.0 58 20.9 5:26 5:26 4 4.7 3.0 56 13.7 3 8.5 3.0 106 8.5 8:04 16:08 6 4.3 4.0 78 17.8 11 :44 11 :44 4 5.8 3.0 69 25.3 14:00 21:03 5 5.3 3.5 54 40.3 20:13 20:13 3.7 5.1 2.6 69 38.8 18:59 23:22 3.1 4 1.8 77 43.6 10:51 10:51 3.5 4.6 2.5 67 22.7 9:49 17:27 4 4.7 2.2 76 33.7 15:10 22:46 4.5 7 3.0 85 45.0 1:16 0:39 3.5 5.5 3.0 66 6.7 11:16 18:25 4.5 5.5 2.9 71 35.7 RIONODURA 11 :13 28:03 4 2.9 4.0 56 49.7 10:32 26:21 4 4.9 2.5 63 49.4 15:50 31:40 5 6.1 3.0 72 62.1 8:41 21:42 5.5 7.2 3.5 57 44.6 9:06 27:18 5.5 7.1 4.5 55 53.4 7:06 15:05 7.5 5.3 5.0 26 33.6 10:40 21:20 6 2.5 3.5 26 45.4 5 4.2 5.0 30 4.2 4 4.4 4.0 40 4.4 6 7 5.5 48 7.7 5 6.3 5.0 33 6.3 6:39 15:36 5.2 5.3 4.1 46 32.8 ~UROEDUS 46:26 46:26 ' 4 5.1 3.0 40 68.4 24:25 36:38 5.5 3.3 3.0 79 69.7 24:04 48:08 6 5.4 4.5 62 76.6 25 :15 50:29 4.5 7 3.5 60 73.1 13:36 40:48 5.5 8.7 5.0 46 14.1 12:16 36:48 6 7 3.0 49 11.4 20:13 40:25 3.5 5 3.0 37 13.8 4 4.1 4.0 61 83.5 4.5 5.7 4.5 43 86.4 3.5 4.7 3.5 72 91.8 16:38 30:00 4.7 5.6 3.7 55 58.9

days (N= 3) for A. crassirostris and CBF (pers. obs.) 21 days (N=3) for A. melanotis. Thus these ages are very approximate only.

3These figures include visits to the nest with and without nestling meals. AUSTRALIAN 112 FRITH & FRITH BIRD WATCHER fruits at a visit. The female appeared to carry almost all meals between the mandibles and in the throat. Once she made head and neck movements as if regurgitating, but may have merely been dislodging food from her throat. Our observations indicate that the nestling diet includes both fruit and insects. Whilst approximately 4 to 7 days old the nestling was fed small and perhaps masticated foods, and observed attempts by it to take whole fruits failed until it was about 9 days old. The fledgling observed by Warham (1962, p. 29) had been fed on fruit with a reddish pericarp. Jackson (1909, pp. 83-84) examined two faeces from a nestling and found the remains of'ten families of Coleoptera' and seeds of a fig Ficus sp. The female of nest 2 was clearly seen to swallow nestling faeces from the nest-cup floor and direct from the nestling from 29 November to 14 December inclusive, and on 15 December she was seen feeding her approximately 22- day-old fledged young one metre below the nest. Jackson (in Marshall 1951, p. 754) apparently had a record or records of fledged young still being fed in April.

Nest and nestling defence On 28 and 29 November and 11 December the nest 2 female was seen to vigorously chase off other Tooth-bills coming within several metres of her nest, whilst on several occasions she ignored Brown Cuckoo-Doves Macropygia amboinensis, Large-billed Scrubwrens Sericomis magnirostris, Grey FantailsRhipidurafuliginosa and Victoria's Riflebirds which forag:1 within a metre or two of the nest. Female Tooth-billed Bowerbirds invariably approached the nest by flying rapidly into lower foliage or the lower part of the vine-entangled nest tree and then hopped in a zig-zag fashion up through the vine tangle to the nest rim. This behaviour, whilst similar to that of female Satin Bowerbirds (R Donaghey pers. comm.) and Great Bowerbirds nucha/is (pers. obs., in prep.), is in marked contrast to the behaviour of parent Spotted Catbirds that typically fly directly on to the nest rim (pers. obs.). This obvious difference in nest approach may well reflect significantly different predatory pressure upon the species at the nest, as monogamous Ailuroedus species appear to have a higher nesting success rate than do uniparental Prionodura (pers. obs., in prep.) and Ptilonorhynchus (Donaghey's 1981 figures for Green Catbird and Satin Bowerbird being 75% and 25% respectively). Warham (1962) reported a single Tooth-bill scolding him and performing a distraction display on the ground as he handled a calling fledgling.

Female behaviour away from the nest Nothing is known of the behaviour of female Tooth-billed Bowerbirds away from the nest because their sex cannot be determined. We assume they are attracted to calling males and visit courts to select a mate. Males do perform display postures on the ground of the courts and mating may take place on or near it, or higher in the forest vegetation. Whilst Marshall (1951, 1954) established that nine calling birds he shot at court were all male he misinterpreted a statement by Jackson (1909, p. 262), thus giving the impression that females have been proven to sing at courts, VOL. 11 (4) DECEMBER 1985 Tooth-billed Bowerbird: Parental Care & Investment 113 like males. He stated that Jackson 'asserts that he collected two females singing above stages' when in fact Jackson stated only that the two females, each found to contain two fertilised eggs, 'were shot at' courts and makes no reference at all to them singing. To understand more of this species we need much more data concerning the morphology, movements and general biology of the elusive adult breeding females and their relationship with court-owning males.

Acknowledgements Bruce Beehler and Dick Donaghey very kindly provided access to their fine Ph.D. thesis material, and the latter commented on a draft of this paper. Andree Griffin and Shelly Lyon performed 4.5 and 2.5 hours of observation respectively. George Heinsohn provided his new distribution record of Scenopoeetes. Patricia White and the RAOU kindly provided library services. John Young kindly provided access to the photographed nest.

References Anon. (1909), 'Notes and exhibits', Proc. Linn Soc. NS. W 33, 799-800. Beehler, B. (1983), 'Frugivory and polygamy in birds of paradise', Auk 100, 1-12. - & Pruett-Jones, S.G. (1983), 'Display dispersion and diet of birds of paradise: a comparison of nine species', Behav. Ecol. Sociobiol 13, 229-238. Berghold, W.H. (1929), 'Egg weights from egg measurements', Auk 46, 466-473. Beruldsen, G. (1980), A Field Guide to Nests and Eggs of Australian Birds, Rigby, Adelaide. Campbell, AJ. (1901), Nests and Eggs of Australian Birds, Pawson & Brailsford, Sheffield. Chaffer, N. (1984), In Quest of Bowerbirds, Rigby, Adelaide. Cooper, W.T. & Forshaw, J.M. (1977), The Birds ofParadise and Bower Birds, Collins, Sydney. Donaghey, RH. (1981), The ecology and evolution of bowerbird mating systems, Ph.D. thesis, Monash University, Melbourne. - , Frith, C.B. & Lill, A. (1985), A Dictionary of Birds, Poyser, Waterhouses. Frith, C. B. & Frith, D.W. (1979), 'Leaf-eating by birds of paradise and bowerbirds', Sunbird 10, 21-23. Gilliard, E.T. (1969), Birds of Paradise and Bower Birds, Weidenfied & Nicholson, London. Griffin, AC.M. (1974), 'Birds of Mount Spec', Sunbird 5, 29-39. Jackson, S.W. (1909), 'In the Barron River Valley, North Queensland', Emu 8, 233-283. Lack, D. (1968), Ecological Adaptations for Breeding in Birds, Methuen, London. Lavery, H.J. & Grimes, R.J. (1974), 'The functions of the bill of the Tooth-billed Bowerbird', Emu 74, 255 -256. LeCroy, M. (1981), 'The genus Paradisaea- display and evolution',Amer. Mus. Novit 2714, 1- 52. Marshall, AJ. (1951), 'Leaf-display and the sexual cycle in the Tooth-billed "Bowerbird" (Scenopoeetes dentirostris Ramsay)', Proc. Zool Soc. Lond. 120, 749-758. - (1954), Bower-birds: Their Displays and Breeding Cycles, O.U.P., Oxford. (1964), Article 'Bowerbird' in Thomson, AL. (Ed.), New Dictionary of Birds, Nelson, London. Preston, F.W. (1974), 'The volume of an egg', Auk 91, 132-138. Schodde, R. (1976), 'Evolution in the birds-of-paradise and bowerbirds, a resynthesis', Proc. 16th Inter. Omith. Cong. Canbe"a, 137-149. Storr, G.M. (1973), List of Queensland Birds, Spec. Pubis West. Aust Mus. no. 5, Perth. Trivers, RL. (1972), 'Parental investment and sexual selection', in Campbell, B. (Ed.), Sexual Selection and the Descent of Man, Heinemann, London. Warham, J. (1962), 'Field notes on Australian bower-birds and catbirds', Emu 62, 1-30• . VOL. 12 (1) MARCH 1987 Records of Birds from Christmas Island 7

Tree Sparrow Passer montanus* Several individuals have frequented the Flying Fish Cove cantilever area since at least March 1983 and possibly for two years beforehand (D. Powell pers. comm.). They are very timid but do not appear to be expanding their range on the Island. They were probably introduced accidentally by ship.

Acknowledgements We sincerely thank all of the Island residents who have reported unusual birds to us over the years, especially D. Powell, H . Yorkston, J. McMaster, J.N. Dunlop and Dr B. Reville. The following people and institutions kindly assisted with the identification of photographs and/or specimens: W. Longmore, W. Boles and T. Lindsey (The Australian Museum), Dr P.J. Fullagar and Dr R. Schodde (Australian National Wildlife Collection, CSIRO), R.E. Johnstone (Western Australian Museum), C. Corben, P. Grant and E.J. van Ijzendoorn.

References Andrews, C.W. (1900), A Monograph of Christmas Island (Indian Ocean), British Museum (Natural History), London. Bailey, R.S., Pocklington, R. & Willis, P.R. (1968) , 'Storm-petrels Oceanodroma spp. in the Indian Ocean', Ibis 110, 27-34. Gibson-Hill, C. A. (compiler) (1947), Papers by various authors on the natural history of Christmas Island in the Indian Ocean, Bull. Raffles Museum 11, 5-177. Gray, H.S. (1981), Christmas Island - Naturally, H.S. Gray, Geraldton, West. Aust. King, B., Woodcock, M. & Dickinson, E.C. (1975), A Field Guide to the Birds of South-East Asia, Collins, London. Mitchell, B.M. (1974), 'The forest flora of Christmas Island', C'wealth For. Rev. 53, 19-29. Pocklington, R. (1979), 'An oceanographic interpretation of seabird distributions in the Indian Ocean', Marine Biology 51, 9-29. Robinson, H.C. & Chasen, F.N. (1936), The Birds of the Malay Peninsula, vol. 3, Witherby, London. Seebohm, H. (1890) , The Birds of the Japanese Empire, Porter, London. Serventy, D.L., Serventy, V. & Warham, J. (1971), The Handbook ofAustralian Seabirds, Reed, Sydney. Van Tets, G.F. (1974), List of bird species found at Christmas Island, in Conservation of Endangered Species on Christmas Island: A Report of the House of Representatives Standing Committee on the Environment and Conservation, Aust. Govt Pub!. Serv., Canberra. - - (1978a), 'Transmarine dispersal of Black Cormorants', A'asian Seabird Group News!. 10, 21-24. - - (1978b), 'Transmarine dispersal of Australian Pelicans', A 'asian Seabird Group News!. 11, 5-6. --(1983), List of bird species found at Christmas Island, Annex E in The Preservation of Abbott's Booby on Christmas Island, Report of the Senate Standing Committee on Science, Technology and the Environment, Aust. Govt Pub!. Serv., Canberra. •

Corrigenda- Yo!. 11 no. 3 'The Black Falcon Falco subniger: a summary of information and comparison with the Brown Falcon Falco berigora': in the discussion of display vocalisations (p. 88), Austin's report of Black Falcon calls should read 'parrot-like notes unusual for a falcon'.

Vol. 11 no. 4 'Parental care and investment in the Tooth-billed Bowerbird Scenopoeetes dentirostris (Ptilonorhynchidae)' : in the discussion of nest and nestling defence (p. 112), the quoted figure for Green Catbird nesting success rate should have been 65%, not 75%. This does not affect the conclusions regarding breeding systems in the catbirds versus bowerbirds.