AUSTRALIAN 260 WATCHER

AUSTRALIAN BIRD WATCHER I994, IS, 260-264 Mixed Flocks in Northern

by BRYAN SAGE, Waveney House, Waveney Close, Wells-next-the-Sea, Norfolk NR23 lHU, England

Summary Mixed-species flocks of (Meliphagidae) were observed at two sites in northern Queensland in June 1992. The first record concerned six species of six different genera in the Gregory River area, and the second ten species from seven different genera on Cape York Peninsula. The first record of Yellow-throated Miner Manorina jlavigula for Cape York Peninsula is presented. Introduction In June 1992 mixed-species flocks of honeyeaters were encountered at two localities in northern Queensland, and a few aspects of these observations warrant comment. The first record was on 9 June near the Gregory River just to the east of Lawn Hill National Park (18 °45 'S, 138 ~3 'E), and the second was on 16 June on Artemis Station south of Coen (13 o57 'S, 143 o12 'E) on Cape York Peninsula.

The Gregory River Site The habitat here was open eucalypt woodland dominated by Silver Box pruinosa on open spear grass flats (probably Variable Spear Grass Stipa drummondii). A flock of 40-45 honeyeaters of six species in six different genera was watched working through the woodland and evidently feeding primarily on invertebrates rather than nectar, and about 25 of these were Banded Honeyeaters Certhionyx pectoralis. Other species in this mixed flock comprised Yellow-tinted Honeyeater Lichenostomus flavescens, Lichmera indistincta, Golden-backed race of the Black­ chinned Honeyeater Melithreptus gularis laetior (3+), Rufous-throated Honeyeater Conopophila rufogularis (only 2 seen), and Little Philemon citreogularis (2 +). Movement of the flock through the trees was fairly rapid and the feeding methods used were mostly flitting and gleaning (see Brooker et al. 1990) in both the inner and outer foliage and at most levels, although Little were seen only in the upper canopy. In the case of the Brown and Rufous-throated Honeyeaters, some individuals were seen hawking from the canopy. Tree Martins Cecropis nigricans were also present feeding over the canopy, but evidently had no direct connection with the honeyeater flock.

The Cape York site The habitat here was alluvial grassland with open eucalypt woodland in which the dominant species is the Broad-leaved Carbeen Eucalyptus confertiflora, with which are associated other species such as Long-fruited Bloodwood E. polycarpa and (species not determined). The honeyeater flock here consisted of75+ (possibly as many as 100) of 10 species in seven different genera. The most numerous species was the Blue-faced Honeyeater Entomyzon cyanotis (c. 35+). Other species in this loose flock were Yellow Honeyeater Lichenostomusflavus, , Brown Honeyeater, White-throated Honeyeater Melithreptus albogularis, Golden­ backed Honeyeater (scarce), Yellow-throated Miner Manorinaflavigula (at least three), , Silver-crowned Friarbird Philemon argenticeps and P buceroides (one only). As at the Gregory River, the movement of the flock through the trees was quite rapid and owing to the high level of activity it was not possible, with the exceptions given above, to specify the numbers of most species. The foraging behaviour of the various species was noted and the methods used were flitting, gleaning, VOL. 15 (6) JUNE 1994 Mixed Honeyeater Flocks, Queensland 261

Rufous-throated Honeyeater Conopophila rufogularis Plate 39 Photo: G.A. Cumming

Brown Honeyeater Lichmera indistincta Plate 40 Photo: N. Male AUSTRALIAN 262 SAGE BIRD WATCHER hovering, hawking and probing (Brooker et a!. 1990). The niches being exploited included the foliage (inner and outer) at all levels, limbs and branches in the upper canopy and lower down, the trunk, ground (Blue-faced Honeyeater only) and aerial (Banded, Brown and Yellow Honeyeaters). All three species of friarbird foraged entirely in the inner and outer foliage and tended to stay in or just below the upper canopy. Although some trees were in flower the main prey being exploited was, as at the Gregory River site, primarily invertebrates; only individuals of the Brown and Golden-backed Honeyeaters and Little Friarbird were seen to take nectar occasionally.

Discussion The Australian honeyeaters form a diverse and successful family that exhibits a wide range of food, feeding behaviour, and social and breeding behaviour. Some species (for example Yellow-throated Miner) are normally largely sedentary, whereas others (such as Little Friarbird and Brown Honeyeater) are nomadic, some highly so. In broad terms honeyeaters can be separated into two guilds based on relative beak length (Ford 1979) - nectarivorous and insectivorous - although most species exploit both food sources (see McFarland & Ford 1991). In the two instances discussed here, although the flocks contained species from both guilds, the food source being exploited was predominantly invertebrate. The observations on feeding behaviour given above are in close agreement with the results obtained by Brooker et al. (1990) in , Northern Territory. They found that most honeyeaters have a generalised feeding ecology, with only a small number showing specialisation in foraging height, site or behaviour, and do not often forage for invertebrates on the ground. The latter type of behaviour was noted only for the Blue-faced Honeyeater on Cape York in the present study. In discussing mixed flocks of birds in New Guinea, Diamond (1987) recognised the 'bird wave' as a separate phenomenon. The wave may comprise dozens of forest bird species and up to nearly 100 individuals. An example of this behaviour has been described by Sedgwick (1988) from the Kimberley District of Western Australia, in which perhaps thousands of birds were involved. Although Sedgwick's wave included four species of honeyeater, various non-honeyeater species were also involved, which was not the case in the Gregory River and Cape York observations described here. The species composition of the flock seen at the Gregory River location has no unusual features. The main species concerned, the Banded Honeyeater, is markedly nomadic (Keast 1968) and loose flocks are known to form in areas where trees flower prolifically, and it is also very common in some places in the breeding season. The Brown Honeyeater is a highly versatile and opportunistic species throughout its range (Keast 1968) . The Golden-backed Honeyeater is a known blossom nomad in the north; the Rufous-throated Honeyeater is markedly nomadic, and the Little Friarbird is a blossom nomad over most of its range. In contrast with these species, the Yellow­ tinted Honeyeater is mainly sedentary but may undertake local movements (Longmore 1991). The word nomadic is used here for want of a better term, but in fact there is still much to learn about both local and long-distance movements. The Cape York observation is of rather more interest. Six of the species recorded here (Banded, Blue-faced and Brown Honeyeaters; Little, Helmeted and Silver-crowned Friarbirds) are all primarily nectarivorous, whereas the remaining four species (Golden­ backed, White-throated and Yellow Honeyeaters, and Yellow-throated Miner) are primarily insectivorous. With the exception of the last species, all breed on Cape York Peninsula and all are at least locally nomadic. There seem to be two main points of interest here, the first being the high species (10) and generic (7) diversity represented in this flock , as opposed to a bird 'wave'. According to Frith (1976) the Blue-faced VOL. 15 (6) JUNE 1994 Mixed Honeyeater Flocks, Queensland 263

Yellow Honeyeater Lichenostomus jlavus Plate 41 Photo: G.A. Cumming

Helmeted Friarbird Philemon buceroides Plate 42 Photo: G.A. Cumming AUSTRALIAN 264 SAGE BIRD WATCHER

Honeyeater is found commonly in mixed feeding flocks which may contain six to eight birds, although as many as 30 may be together; in the present case the flock contained a minimum of 75 birds of which 35+ were of this species. The main point of interest, however, was the presence of three Yellow-throated Miners in this mixed flock. This species has apparently not been recorded previously from Cape York Peninsula proper and is generally understood to be sedentary (Keast 1968). In Blakers et al. (1984) no records of this species are shown north of latitude 17 o S in northern Queensland. There was no suggestion from the Field Atlas data of large-scale seasonal movements. Its occurrence just south of Coen is therefore a considerable distance north of its normal range. It is, perhaps, worth noting that Frith (1976) stated that the Blue-faced Honeyeater is usually associated with Yellow-throated Miners and friarbirds in mixed flocks and with Noisy Miners Manorina melanocephala in coastal areas.

Acknowledgement I thank Simon Nevill of Falcon Tours, Perth, without whom our ten-week expedition in the outback would not have been possible.

References Blakers, M. , Davies, S.J.J.F. & Reilly, P.N. (1984), The Atlas of Australian Birds, Melbourne University Press, Melbourne. Brooker, M.G. , Braithwaite, R.W. & Estbergs, J.A. (1990), 'Foraging ecology of some insectivorous and nectarivorous species of birds in forests and woodlands of the wet-dry tropics of Australia', Emu 90, 215-230. Diamond, J.M. (1987) , 'Flocks of brown and black New Guinea birds: a bicoloured mixed species foraging association', Emu 87, 201-211. Ford, H.A., (1979), 'Interspecific competition in Australian honeyeaters - depletion of common resources', Aust. J. Ecology 4, 145-164. Frith, H.J. (Ed.) (1976), Reader's Digest Complete Book of Australian Birds, Reader's Digest Services, Sydney. Keast, A. (1968) , 'Seasonal movements in the Austmlian honeyeaters (Meliphagidae) and their ecological significance', Emu 67, 159-209. Longmore, W. (1991), Honeyeaters and Their Allies of Australia, Collins Angus & Robertson, Sydney. McFarland, D. & Ford. H.A. (1991), 'The relationship between foraging ecology and social behaviour in Australian honeyeaters', Acta XX Congressus Internationalis Ornitholigici, 1141-1155. Sedgwick, E.H. (1988), 'An Australian bird wave', Aust. Bird Ubtcher U, 241. Received 22 July 1993 •