Size and Age Parameters of Nest Trees Used by Four Species of Parrot and One Species of Cockatoo in South-west Australia

148 EMU Vol. 94. 1994 Gill, F.B. 1990. Ornithology. Freeman, New York. Hutchinson, J.N. 1971. Australian Bird Calls. Series 1 (tape recordings of 50 species, including White-plumed Honeyeater). Balingup, Western Australia. Klump, G.M., Kretzschmar, E. & Curio, E. 1986. The hearing of an avian predator and its avian prey. Behavioral Ecology and Sociobiology 18, 317-323. Marler, P. 1955. Characteristics of some animal calls. Nature 176, 6-8. Marler, P. 1957. Specific distinctiveness in the communication signals of birds. Behaviour 11,13-39. Marten, K. & Marler, P. 1977. Sound transmission and its significance for animal vocalisations 1. Temperate habitats. Behavioral Ecology and Sociobiology 2, 271-290. Morton, E.S. 1975. Ecological sources of selection on avian sounds. American Naturalist 109, 17-34. Nottebohm, F. 1975. Vocal behavior in birds. Pp. 287-332 in Avian Biology, Vol 5. Eds D.S. Famer & J.R. King. Academic Press, New York. O'Brien, P.H. & Dow, D.D. 1979. Vocalisations of nestling Noisy Miners Manorina melanocephala. Emu 79, 63-70. Pettifor, R.A. 1990. The effects of avian mobbing on a potential predator, the European Kestrel, Falco tinnunculus. Animal Behaviour 39, 821-827. Pizzey, G. 1980. A Field Guide to the Birds of Australia. Collins, Sydney. Rooke, I.J. 1972. The vocal repertoire of the White-plumed Honeyeater. B.Sc. (Hons) Thesis, Monash University, Melbourne. Rooke, I.J. & Knight, T.A. 1977. Alarm calls of honeyeaters with reference to locating sources of sound. Emu 77, 193-198. Simpson, K. & Day, N. 1988. Field Guide to the Birds of Australia. Viking O'Neil, Melbourne. Slater, P., Slater, P. & Slater, R. 1986. The Slater Field Guide to Australian Birds. Rigby, Sydney. Stefanski, R.A. & Falls, J.B. 1972a. A study of distress calls of Song, Swamp and White-throated Sparrows (Aves: Fringillidae). 1. Intraspecific responses and functions. Canadian Journal of Zoology 50, 1501-1512. Stefanski, R.A. & Falls, J.B. 1972b. A study of distress calls of Song, Swamp, and White-throated Sparrows (Aves: Fringillidae). 2. Interspecific responses and properties used in recognition. Canadian Journal of Zoology 50. 1513-1525. Whitmore, M.J. & Eller, C.M. 1983. Observations at a nest of Painted Honeyeaters. Emu 83, 199-202. EMU Vol. 94, 149-155, 1994 © Royal Australasian Ornithologists Union 1994 0158-4197/94/03149 + 6 Received 13-8-1992, accepted 16-4-1993 Size and Age Parameters of Nest Trees Use£ by Four Species of Parrot and One Spec.es of Cockatoo in South-west Australia P.R. Mawson1 and J.L. Long2 C„„^ctfipld W A. 6058 1 Agriculture Protection Board of Western Australia, Bougainvtllea Avenue, 2 47 Buckingham Road, Kelmscott, W.A. 6111 Summary: The size and health of hollow-bearing eucalypts successfully used by four species of parrot and one species of cockatoo in the south-west of Western Australia are described. The estimated age of these nest trees based on known growth rates is given and ranged from 73 years o over 1300 years. The lowest average estimated age ot ne trees recorded for any of the parrot species was 2 years, and 446 years for the cockatoo species. In view ot current timber production strategies and management policies tor remnants of nest hollows may be in ^^dsupp) qws near future. To ensure a continued sqjW 0 timber for parrots it will be nece^uy » ™dr* e fof production strategies in , research into the management of small remnants of nafve vegetal,on. Hollows in eucalypt trees are used as nest chambers by some 50 species of Australian parrots and cockatoos (Forshaw 1981). A further 21 bird species use hollows in trees for shelter or as nests (Saunders et al 1982), and most possums and gliders (Inions et al. , Mackowski 1984; Lindenmayer et al. 1990), bats (laylor & Savva 1988; Lunney et al. 1988) and some dasyurids (Cuttle 1982) shelter in them. The process by which hollows are formed in eucalypts is typically initiated by wood fungi, with termites contributing to the process some time after they have become well established (Saunders 1979; Mackowski 1984). When water or moisture enters the decaying wood the debris drain down the inside of the trunk or branch, or empties out of the tree through fissures or cracks. The result is a cavity in the tree. When branches or stems break, the remaining section provides a hollow which birds and mammals can use as a shelter or a nest chamber. Small holes or cracks in branches and stems can also be enlarged by parrots and cockatoos although these modifications never amount to excavations ot limbs. Once hollows have been formed they may be enlarged during high intensity fires, or completely destroyed (Inions et al. 1989). Hot fires may also directly create new hollows by burning through the outer wood and into the rotted centre of the branch or trunk. Development or modification of land once covered with eucalypt trees for agriculture, urban development and mining invariably removes the tree cover. Managemerit of state forest for timber production and fire control alters the characteristics of the lores s. forestation programs replace ^ wavs with the same species or at the same den. seldom if ever are new plantings left for long eno g form hollows before they are harvested This paper describes the size and age of tree spec that contain holtows suitable for nesting by ^ Parrot Polytelis anlhopeplus. RedpcaPP®d us nureicephatus spurius. Western Rosella Platycercus iceoisfon Lincoln R.ngneck Barnard,us ,onar,us mid the Western Long-billed Core,la C*~a, pastor pastinator. We discuss the implications of the cu rent land management practices with regard to their effect on four species of small parrot and one cockato and other hollow users which inhabit the south-west of Western Australia. Methods Observations and measurements of Bees in which the paiTotl and cockatoo nested were taken opportuntstically over a four-year period, 1989-92. Tbe nes s; o Regent Parrots, Port Lincoln Rtngnecks and Western Rosellas at Wickepin and Port Lincoln Rtngnecks and Red-capped Parrots at Byford were known to have contained successful clutches (Long «h ThenesB^of ,r Parrots. Port Lincoln Rtngnecks, Western Rosel- 150 EMU Vol. 94, 1994 las and Red-capped Parrots at Woodanilling and Boscabel and the Long-billed Corellas at Lake Muir-Tone Bridge were observed only from the ground. Based on the behaviour of adult birds and the appearance of fledgling young in some of the hollows these nests were considered to have been successful. The diameter at breast height, outside the bark (DBHOB), of each tree containing a successful nest hollow was measured and recorded. The general health of the trees was noted and the condition of the stand in which they occurred was assessed, in particular the presence of seedling and sapling trees. The nests were located at several localities in the south-west of Western Australia. Data were collected on nests of Regent Parrots, Port Lincoln Ringnecks and Western Rosellas in Salmon Gum Eucalyptus salmonophloia and Wandoo E. wandoo woodland near Wickepin (200 km SSE of Perth) and at Woodanilling (230 km SE of Perth). Nests of Red-capped Parrots and Western Rosellas in Jarrah E. marginata and Wandoo Table 1 Age and size (DBHOB) of trees used by four species of parrot and one species of cockatoo for nesting in the south-west of Western Australia. Values are means ± standard deviations, with ranges in italics. Sample sizes (n) as indicated. Eucalyptus Eucalyptus Eucalyptus Eucalyptus Eucalyptus marginata calophylla salmonophloia wandoo rudis Long-billed Corella Age (yrs) Diam. (mm) Regent Parrot Age (yrs) Diam. (mm) Port Lincoln Ringneck Age (yrs) Diam. (mm) n Western Rosella Age (yrs) Diam. (mm) Red-capped Parrot Age (yrs) Diam. (mm) 1061 ± 194 680-1333 1061 ±193 680-1333 16 862 862 1 600 600 1 806 ± 259 520-1435 806 ± 259 520-1435 446 ± 222 167-931 12831251 880-1719 15 436 ± 33 121-629 793 ± 203 207-1069 17 275 468 346 ± 221 122-921 6921156 460-1010 21 429 1 455 73-1935 696 1 238 325-1260 35 2901214 73-921 6251194 325-1010 23 285 1 202 73-475 6171259 325-820 ? ? 893 1 97 795-990 2 ? ? 995 1 168 748-1474 Mawson & Long: Parrot and Cockatoo Nest Trees were located near Boscabel (225 km SE of Perth). Data on Red-capped Parrot and Port Lincoln Ringneck nests in Flooded Gum E. rudis stands were collected near Byford (35 km S of Perth). The data on Long-billed Corella nests in Jarrah and Marri E. calophylla were collected in remnant forest, road verges and private property near Tone Bridge (265 km SE ol Perth). For each species of nest tree measured, the age ol individual trees was calculated using published figures for growth rates, where known (£. marginata, Abbott & Loneragan 1983; E. salmonophloia, Keally 1989) an unpublished data (£. calophylla and E. wandoo, M. Rayner pers. comm.). No growth rates were available for E. rudis but DBHOB measurements recorded tor this species of tree are included for comparison. The growth rates used to calculate the age ol Wandoo are based on only 12 specimens and may not be as accurate as the rates for other species. The growth rates for Salmon Gum are based on measurements ot only one regrowth stand (total 156 trees) and are unlikely to be typical of growth rates for this species in all rainfall zones. However, for the purpose of this paper they provide a useful guide to the age of trees used by parrots and cockatoos for nest hollows. In situations where more than one growth rate is available for a species growing in areas of differing rainfall, the rate appropriate to the location of the nest tree was used. Results This study showed that the trees used by the Longbilled Corella and the four species of parrot were invariably very large and very old (Table 1). The minimum estimated age recorded for any tree with a nesting hollow used by the parrots was 73 years and 167 years for the Long-billed Corella. The lowest average age recorded for any species of tree with a nest hollow suitable for parrots was 275 years (E. salmonophloia). Long-billed Corella Nest hollows of Long-billed Corellas were all located in the Lake Muir—Tone Bridge area and all were in very large trees that were either mature, or over-mature and dying. Typically, the crowns of these trees had dead limbs and a very open canopy. No nest hollows were recorded in trees with dense, healthy canopies. All of the trees with Long-billed Corella nesting hollows were located in cleared pasture (where they served as shade trees for stock), on roadside verges or were in remnant vegetation adjacent to farms or pine plantations. Few, if forest. Regent Parrot ^unPubl" biology of this species (Long 1989). in these'were healthy or had few dead branches in the crowns By 1990, only 54% of them were in the same condition^and 7% had'died and/on fallen over Mosof these Salmon Gums were situated on a roadside verge or a stand in an adjoining paddock thai by sheep, burnt and was showing signs ot bec°™ g salt affected. No saplings or seedlings were presen dicating that this stand of trees will cease to exist if no replacement trees are planted. The Salmon Gum^nd Wandoo at Woodanilling which contain RcgentPam nests are all healthy. However, the stands have been subjected to grazing by sheep and rabbits and althou® sheep have been excluded from one of these sta"ds 12 years, there is no evidence of seedling trees and y a few small sapling Wandoo are regenerating from lignotubers. Port Lincoln Ringnecks, Western Rosellas and Red-capped Parrots Nearly all Wandoo trees used as nest trees by Port Lincoln Ringnecks and Western Rosellas were healthy, bu there were very few saplings and no seedlings growing at either Wickipin or Woodanilling. Most of the Red-capped Parrot and Western Rosella nests located in the mixed Jarrah-Wandoo stand at Boscabel were in healthy trees. The stand was logged in the 1950s for commercial grade timber leaving lew large, quality trees. The stand was protected by the landowners several years ago when they became concerned at the damage being caused to the understorey from grazing by sheep. However, there are now few it any saplings or seedlings present. All nesting hollows of Red-capped Parrots recorded in Flooded Gum at Byford were located in grazed paddocks. These trees have declined in health only slightly since 1974 and the majority are still in good health. Flooded Gums in this stand are larger than any growing along the narrow road verges nearby. No seedlings are present in the paddocks, which are grazed by cattle, but there are numerous advanced saplings present. 152 EMU Vol. 94, 1994 Competition for nesting hollows from Galahs and feral bees During this study it was noted that several hollows which had formerly been used by parrots had been taken over by either Galahs Cacatua roseicapilla or feral bees Apis mellifera. Galahs have been expanding their range south into the south-west comer of the state since the early 1950s (Rowley 1990), as a result of the clearing of forested areas for agriculture. The majority of Galah nests were located in hollows in Salmon Gums. Several of these hollows were known to have been occupied by Regent Parrots in the recent past. Hollows occupied by feral bees were recorded in Salmon Gums, Wandoo, Jarrah and Flooded Gum. A few of these hollows were known to have been used by parrots in the past. Discussion The time required for hollows to form in any species of eucalypt is governed partly by natural processes and partly by the growth rate of the tree, neither of which can be hastened. If there is insufficient time for trees to reach the minimum size at which hollows form before the trees are cut down then at some time in the future no suitable nest hollows will be available for parrots and cockatoos. How far into the future nests will cease to be available depends on several factors. Commercial timber harvesting for saw logs and wood chips is the major factor in the Jarrah-Marri forests of the southwest (see Saunders et al. 1985). In the wheatbelt, clearing for agriculture, road development and the suite of lesser elements that constitute rural dieback (Landsburg et al. 1990) are the main factors. The results presented in Table 1 indicate that even small species of parrot require large, old trees to nest in. A medium-sized cockatoo such as the Long-billed Corella requires larger and extremely old trees. The average diameter of nest trees used by the parrots is very similar regardless of the species of eucalypt involved. Comparable data on trees with nest hollows have been reported by Saunders et al. (1982) for parrots and cockatoos in the wheatbelt areas north-east of Perth (almost all from Salmon Gum), corellas in the central wheatbelt (Smith 1991) and from eastern Australia for the Superb Parrot Polytelis swainsonii (Webster 1989) and the rare Victorian subspecies of the Red-tailed Black-Cockatoo Calyptorhynchus banksii graptogyne (Joseph et al. 1991), the latter two species nesting predominantly in River Red Gum E. camaldulensis. At present Jarrah and Marri are harvested commercially for timber and woodchips. In general the larger Jarrah are selected preferentially as they provide the best timber, while the largest Marri provide the greatest volume of woodchips for paper pulp. The harvest of Jarrah is currently on a 100-year rotation; there is no set period between harvests of Marri. The current timber strategy considers large old trees unsuitable for felling, as elements that inhibit regrowth development and which should be removed (Anon. 1987). No significant areas of original forest which have not been cut for timber remain, except in national parks or conservation reserves. In areas of forest designated for 'multiple use management' timber production and preservation of old growth virgin forest are incompatible (Anon. 1987). As such, conservation of hollows (for parrots, cockatoos and other cavity dwelling fauna) and timber production must be regarded as incompatible. Agricultural development is now limited in Western Australia and no more crown land is to be released for development. There are also restrictions on the clearing of any areas of native vegetation, including regrowth, remaining on private land. However, the large shade trees seen in paddocks today are slowly being lost due to damage by stock, exposure and the combined elements of rural dieback (salt, water stress, herbicides and insect attack). Because many of our country roads are continually upgraded and widened to accomodate larger vehicles and volumes of traffic, the remaining stands of trees on roadside verges are gradually being lost or depleted. Frequent burning of roadside verges has also prevented seedlings from establishing and providing replacements for mature trees. In some remnants a complete absence of fire may also be preventing germination and seedling establishment. How the present decline in availabile trees with nest hollows affects various populations of parrots and cockatoos is unknown. For most species it does not appear to be having any immediate or obvious influence. This is not unexpected given that hollow availability has been shown to exceed population requirements in some areas (see Saunders et al. 1982; Saunders & Ingram 1987; Long 1989). However, the Long-billed Corella is now listed as Rare and Endangered (Government Gazette, November 1990) and the Lake Muir population may be less than 1500 birds (Massam & Long 1992). A substantial reduction in suitable nest trees could seriMawson & Long: Parrot and Cockatoo Nest Trees ously affect the chance of survival of this and other fr°® ra^be addressed_to some degree* ,0lfttTuSe for nesting continue to he lost at the current rate, firstly the larger cockatoos will be affected man » (ed management of the small remnant of as the largest and oldest trees are removed, then the etation scattered throughout thc whcatbeh i small parrots which have more special requu-ements ™ d government authorities rarely have the re- (e.g. particular diet requirements and proximity of feedneeded. ; necessary to readily manage tag areas to nest trees). The greatest problem assoc.a ed ^ patches of native vegetation with this slow loss of suitable nesting trees is that . for management ot such rem may well go unnoticed for a long time. Many parrots and here is a S^..^ and cockatoos are long-lived and may well survive ^ |and management practices change o many years although there are no nesting hollows for Bu^ cockatoos in some areas may breeding. We will see them flying taound. but only ™mow, som panm ^ ^ ^ when the cohort of old birds dies will we notice hat be without eno ^ ^ ^ brfQre a new f there has been no recruitment and that the populatio futin . P obviously too long a period for has undergone a sudden decline. By this t.me ,t will "est hoi owsjomis is ^ probably be too late to reverse the process. an> p artificial nest hollows. Little work The Red-tailed Black Cockatoo Calyptorhynchus t on the value of aitifibanksii naso and Baudin's Cockatoo C. baudinn both has been ^ducted ^ mammals (Breck. nest in hollows in large mature trees. The former nes s Cia neshollowsto nat ]989; Menkhorst in Marri and possibily Jarrah trees while the latter nes woldt , 99Q) This is an area which in Marri and Karri E. diversicolo, Red-tailedBlack 1984a^ ^ Jhe imroduction of Cockatoos will be subject to greater pressures from forshould be *ddr de2raded habitat or regenerest management practices than other species t a u arti lcia nes d d ter catchments, is a task Jarrah and Marr, for breeding because it ated areas by members of local largest nesting hollows (see Saunders et al. 1982 Saum which can be y Ust ornithologists or ders er al. 1985). Baudin's Cockatoo must contend with communities amateur^^^ ^ ^ ^ the loss of the larger Marri trees to woodchipping a interested com y . programs designed to the current policy of clear-felling and ash-bed regene aready contributed ^^^^(Saundcrs 1990). tion used for Karri (Borg et al. 1987). The logging rotaaddress and cockatoo species tion for Karri is 100 years and it is estimated that there The future for the ^ P^t ^ because will be no virgin Karri forest outside national par . y in some areas • nesting, couthe year 2035 (Anon. 1987). ofthe size and age of the trees rmea es While primary products derived from forestry and pled wlth ,he conunerctal ttmber ^ ^ agriculture are vital to our economy the Pontes and (100 matrons andUhe of ,rees methods employed to obtain them are in question. Cu - ,ings and seedlings n many mnman ^ ^ rently the dominanl strategy in forest management is Action can be taken today to:slow an ^ ^ ^ ^ one of zoning the forest estate into categories, either for continued loss of exlstl"S tQ be don£ if wood utilisation or conservation, with only limitedlevithere 1S a great dealimo ^ size and dence to show that the two categories are not mutually future trees are to germinate and g exclusive (Davey & Norton 1990). In Western Australia ag£ required to form hollows, forest management policies are not as yet well deve - oped (Bradshaw et al. 1991). Little research has gone cknowledgementS into alternative management systems such as those u Drovided by Ray Garstone and Wayne cussed by Recher (1985), Recher et al. (1987) and The generous help Pr™deddy y j trees at woodanDavey (1989) where it was suggested that logging be Zadow m showing u thejairot We would carried out in such a way that reserves, unsuitable: timd mg md ®^*Uu5lan MeCaw of the Department of ber and drainage lines remain [inked by unogge Conservation and Land Management for access to unpub- 154 EMU Vol. 94. 1994 Marion Massam (Agriculture Protection Board) in locating and measuring the Long-billed Corella nest trees is also gratefully acknowledged. We are grateful to a number of people for commenting on drafts of this paper including Ron Johnstone and Ray Garstone, and particularly Denis Saunders and Graeme Smith for their advice and criticism. References Abbott, I. & Loneragan, O. 1983. Growth rate and long-term population dynamics of Jarrah (Eucalyptus marginata Donn ex Sm.) regeneration in Western Australian forest. Australian Journal of Botany 32, 353-362. Anon. 1987. Timber production in Western Australia: A strategy to take W.A.'s south-west forests into the 21st century. Department of Conservation and Land Management, Western Australia. Anon. 1992. Management Strategies for the South-west Forests of Western Australia: A Review. Draft for public comment. February 1992. Department of Conservation and Land Management. Borg, H., Stoneman, G.L. & Ward, C.G. 1987. Stream and ground water response to logging and subsequent regeneration in the southern forest of Western Australia. Department of Conservation and Land Management W.A. Technical report No.16. Bradshaw, F.J., Adams, R., Sneeuwjagt, R., Low, K., Havel, J.J., Bartle, J.R. & Stoneman, G.L. 1991. The Jarrah forest: A case study in multiple use. Pp. 1-21 in Forest Management in Australia. Eds F.H. McKinnell, E.R. Hopkins & J.E.D. Fox. Surrey Beatty, Sydney. Breckwoldt, R. 1983. Wildlife in the Home Paddock: Nature Conservation for Australian Farmers. Angus & Robertson, Sydney. Cuttle, P. 1982. A preliminary report on aspects of the behaviour of the dasyurid marsupial Phascogale lapaolafa Pp. 325-332 in Carnivorous Marsupials. Ed. M. Archer. Royal Zoological Society New South Wales, Sydney. Davey, S.M. 1989. Thoughts towards a forest wildlife management strategy. Australian Forestry 52, 56-67. Davey, S.M. & Norton, T.W. 1990. State forests in Australia and their role in wildlife conservation. Proceedings of the Ecological Society of Australia 16, 323-45. Forshaw, J.M. 1981. Australian Parrots. Lansdowne, Melbourne. Hicks, J. & Greenwood. D. 1989. Rescuing Norfolk Island's Parrot. Birds International 1(4); 34-47. Inions, G.B., Tanton. M.T. & Davey, S.M. 1989. Effect of fire on the availablility of hollows in trees used by the Common Brushtail Possum, Trichosurus vulpecula Kerr. 1792. and the Ringtail Possum, Pseudocheirus peregrinus Boddaerts, 1785. Australian Wildlife Research 16, 449-458. Joseph, L., Emison, W.B. & Bren, W.M. 1991. Critical assessment of the conservation status of Red-tailed BlackCockatoos in south-eastern Australia with special reference to nesting requirements. Emu 91, 46-50. Keally, I. 1989. Management of inland arid and semi-arid woodland forest of Western Australia. Pp. 286-295 in Forest Management in Australia. Eds F.H. McKinnell. E.R. Hopkins & J.E.D. Fox. Surrey Beatty, Sydney. Landsburg, J., Morse, J. & Khanna, P. 1990. Tree dieback and insect dynamics in remnants of native woodlands on farms. Proceedings of the Ecological Society of Australia 16,149-65. Lindenmayer, D.B., Norton, T.W. & Tanton, M.T. 1990. Differences between wildfire and clearfelling on the structure of montane ash forests of Victoria and their implications for fauna dependent on tree hollows. Australian Forestry 53, 61-68. Long, J.L. 1989. The breeding biology of four species of parrots in the south of Western Australia. Agriculture Protection Board of Western Australia. Technical Series No. 6. Lunney, D., Barker, J., Priddel, D. & O'Connell, M. 1988. Roost selection by Gould's long-eared bat, Nyctophilus gouldii Tomes (Chiroptera: Vespertilionidae) of New South Wales. Australian Wildlife Research 15, 375-384. Mackowski, C.M. 1984. The ontogeny of hollows in Blackbutt (Eucalyptus pilularis ) and its relevance to the management of forests for possums, gliders and timber. Pp. 553-567 in Possums and Gliders. Eds A.P. Smith & I.D. Hume. Australian Mammal Society, Sydney. Massam, M. & Long, J. 1992. Long-billed Corellas have an uncertain status in the south-west of Western Australia. Western Australian Naturalist 19, 30-34. Menkhorst, P.W. 1984a. The application of nest boxes in research and management of possums and gliders. Pp. 517-525 in Possums and Gliders. Eds A.P. Smith & I.D. Hume, Australian Mammal Society, Sydney. Menkhorst. P.W. 1984b. Use of nest boxes by forest vertebrates in Gippsland: Acceptance, preference and demand. Australian Wildlife Research 11, 255-64. Recher, H.F. 1985. A diminishing resource: Mature forest and its role in forest management. Pp. 28-33 in Wildlife Management in the Forests and Forestry-controlled Lands in the Tropics and the Southern Hemisphere. Ed. J. Kikkawa. University of Queensland. Brisbane. Recher, H.F.. Shields, J., Kavanagh, R. & Webb, G. 1987. Retaining remnant mature forest for nature conservation at Eden, New South Wales: a review of theory and practice. Pp. 177-194 in Nature Conservation: The Role of Remnants of Native Vegetation. Eds D.A. Saunders, G.W. Arnold, A.A. Burbidge & A.J.M. Hopkins. Surrey Beatty, Sydney. Rowley, I. 1990. Behavioural Ecology of the Galah Eolophus roseicapillus in the Wheatbelt of Western Australia. Surrey Beatty, Sydney. \lawson & Long: Parrot and Cockatoo Nest Trees Saunders, D.A. 1979. The availability of tree hollows for use as nest sites by White-tailed Black Cockatoos. Australian Wildlife Research 6, 205-216. Saunders, D.A. 1990. The landscape approach to conservation: community involvement, the practical option, us tralian Zoology 26, 49-53. ^ Saunders, D.A., Rowley, I. & Smith, G.T. 1985. The effect of clearing for agriculture on the distribution ofcockatoos in the south-west of Western Australia. Pp-309-321 in Birds of the Eucalypt Forests and Woodlands: Ecology, Conservation, Management. Eds A. Keast, H. . Recher & D. Saunders. RAOU and Surrey Beatty, Sydney. ^ n A Smith G T & Rowley, I. 1982. The availAustralian Wildlife Research 9, 541-555. Smith, G.T. 1991. Breeding ecology of the West^ong^ billed Corella, Cacatua pastinator pastmatoi. TavlorT/& Saw"N.M. .988, Use of rocs, si.es by four species of bats in state forest in s°uth^tem Tasmama. Australian Wildlife Research 15, 637-645. Webster, R. 1989. Superb Parrots and gum trees. Birds national 1, 52-59. Southern Hemisphere Ornithological Congress Professional and amateur ornithologists are adv^^ will be an international conference that has been sche Australasian Ornithologists Union. Although the conducted in Western Australia and organised tthe Roy habitats, delegates who wish that has been planned for 29 September to 4 Octobe jt certain to be a major regional centre Location: The venue has not yet been f.nahsed •althoug^ ^ ^ within easy reach of Perth, Western Australia. Exce e ^ ^ post-conference tours that accommodation ranging from basic to luxury p ArtSQtprn Australia offered to delegates, demonstrate the magnificent natural history of sou - America Antarctica and on Major theme: Birds and their habitats in Australasia, Africa, South America, A subantarctic islands. . fnrost birds Sub-themes: (1) Conservation and management of and zone and forest Dira . (2) Impact of habitat fragmentation on bird communities. (3) Studies of migratory seabirds and waders. (4) Breeding biology and mating systems of southern hemisphere bi d . (5) Abundance and distribution of birds. (6) Plant-animal interactions and pollination. (7) Foraging behaviour in terrestrial bird communities. Further information: Persons seeking additional information shoulc» corrtact the ( ^ President of the Royal Australasian Qrn'tholog'Sts Union ro esscx western Australia 6001; Environmental Biology, Curtin University of Technology, GPO Box U iau/. uenn, TPI FFIL 91 351 7041: Fax. (61 9) 351 2495.