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Thanks to Dick Schodde, Mark Clayton and John Wombey for a wonderfully entertaining and informative evening at the world's best collection of Australian birds. The central table was festooned with specimens, including fascinating ranges of skins from different locations and in different stages of moult. The display included the neotype of Trichoglossus haematodus moluccanus Gmelin, the Rainbow Lorikeet, representing material taken on Cook's first voyage to Australia. Like many Australian type specimens, the original was lost over a hundred years ago. Consequently CSIRO was able to designate a new type specimen, which came from the region of Botany Bay.
Other highlights of the evening included Mark Clayton's demonstration of feather fluorescence under UV light and Jamie Matthew's discussion of moult in Australian passerines.
Jamie used a series of skins to outline examples of different moult strategies. He showed examples of complete moult in the Rufous-throated Honeyeater, and partial post-juvenile moult in Spotted Pardalote and White-eared Honeyeater. Adult moult patterns were also outlined using a series of skins, some adults with complete post-breeding moult (including moult of all primaries), others having suspended moult of primaries.
The discussion went on to outline the differences in moult strategies between different taxa of Australian birds. For example, pardalotes do not moult primaries in their post-juvenile moult, but honeyeaters vary enormously in the extent of post-juvenile moult.
The relevance of museum collections for studies of plumages, moult and geographic variation in birds was mentioned, and the value of the National Australian Wildlife Collection was emphasised.
Dr Matthew's work involves museum collections and data from banding studies, and goes toward the preparation of plumage accounts for the forthcoming Volume 5 of the Handbook of Birds of Australia, New Zealand and Antarctica.
We should all try to be more observant about feather condition and more diligent in recording moult, age, etc in the birds we see.
Thanks to those who provided food for the evening. If you left a plate behind, you can collect it from the sales desk at the next meeting.
Knowing just what to look for if you get a quick glimpse of a thornbill at the top of a tree is half the battle in identifying these small birds, and Richard Allen gave us some good tips at the July and November meetings.
To help us separate out the different species in the Canberra region, Richard has prepared this key to the species. Look in particular for whether the breast is streaked. The Striated and Brown Thornbills have streaked breasts, but the Yellow-rumped, Buff-rumped and Yellow, and the Weebill, do not. The colour of the background to any streaking is also important. The Striated and Yellow Thornbills have yellowish underparts but the underparts of the Brown Thornbill just look pale brown. Also look for whether the eye appears large (Brown) or there is strong patterning on the face (Striated), and the general colour of the back, rump and flanks.
Behavioural characteristics can also help identify the species. Look for:
And, of course, learn the calls.
Thanks to Syd Curtis for a most entertaining talk on lyrebirds.
Syd discussed the vocal behaviour of the Superb Lyrebird as elucidated by the late Norman Robinson, and his own observations of the Albert's Lyrebird. With both species, the elaborate visual display probably evolved in open-floored Antarctic beech forests which later gave way to today's wet sclerophyll and rainforest where dense ground cover required the development of the vocal display.
A male lyrebird uses loud territorial songs to establish and defend an area of habitat, keeping out all other mature males. Syd has heard the territorial song of a male Albert's Lyrebird at a measured map distance of 1.5 km. Recordings of territorial songs illustrated the astonishing amount of regional variation that occurs, especially with the Superb.
Males of both species display on defined courts, using a largely continuous stream of sound consisting mainly of mimicry. With the Albert's Lyrebird, the sounds are arranged into a stereotyped song 40-50 seconds long which may be repeated over and over without a break, the same sounds always coming in the same order. Syd calls this the 'albertcycle'. All males in a particular area use the same albertcycle, and therefore they must be learning to sing by copying mature males, not by directly copying the other species whose calls appear in the song. The Superb's mimicry appears not to be in any particular order.
Unlike the Superb's cleared mound, the Albert's court consists of cris-crossed thin vines or sticks lying loosely on the ground. When the bird is displaying, he steps deliberately from foot to foot on the vines, causing them to spring up and down. If not springy enough, he will grasp a vine and lift it up and down. The movement of the vine is transferred to the screening vegetation, causing leaves to shake up to a metre or more away from the bird. This probably acts as a signal to the female and distracts predators attracted to the display song.
The stream of mimicry of the Superb may be interrupted by territorial songs and by 'plik' songs which have a peculiar rhythmic character. The 'gronking' song of the Albert's Lyrebird is also highly rhythmic, and the bird shakes or taps the vines in time with his song.
Albert's Lyrebird territorial songs are relatively simple, but sometimes in the early morning when it is still too dark for safety on the ground, an Albert's Lyrebird will give a concert from his roost high in a rainforest tree. As Syd said, it is hard to avoid believing that he is singing just for the sheer joy of it as he improvises a whole string of variations on his territorial song.
And those who were not at the meeting missed Glen Threlfo's outstanding video of a very difficult subject. At the end of a long sequence in which the male is displaying on his platform of vines, he finally lowers his tail to the rest position, shakes his feathers and walks off the platform. At the meeting this brought immediate applause, just as if he were a live performer. It was a remarkable and spontaneous reaction to a very beautiful and elaborate performance by a wild bird.
COG's conservation officer, Doug Laing, based his talk at the last meeting on the premise that the interests of conservation and ecosystem integrity in much of Africa are not well served by excluding people from environments which they had been part of for generations. Doug, who lived in Zimbabwe for three years and travelled widely in the region, believes that people must be considered a natural part of many ecosystems or biospheres and sees this recognition as a key to the conservation of many precious areas currently threatened by poverty and population pressures.
Doug pointed out by historical example how colonialism had distorted natural systems by the forced removal of people from traditional lands. Now parks like the Serengeti (Tanzania), Hwange (Zimbabwe) and Etosha (Namibia) are magnets for mass tourism, which is not always compatible with conservation.
Tourism in Africa equates with megafauna, and the parks are increasingly cash cows for cash strapped governments. Where there is no large fauna, there is little tourism but there are precious areas in this category, often with vulnerable species and usually poorly conserved, pressed upon by people from all sides. Without new thinking, these areas will be destroyed.
To illustrate his thesis Doug used many wonderful slides of birds, beginning in his own garden in Harare and then travelling to four very different parts of the country.
He took us first to the Eastern Highlands of Zimbabwe, where three habitats illustrated a range of problems faced by wildlife.
The Chirinda Forest is a tiny afromontane rainforest island surrounded by commercial tea and coffee plantations and poor peasant farmers. It is home to the rare Swynnerton's Robin and the uncommon Starred Robin as well as to mammals like the Sun Squirrel and the Blue Duiker. The tiny Chirinda Apalis is found only in these eastern forest areas.
When Doug visited the forest, a place so precious, only blanket protection seemed appropriate, he was met by a man on a bicycle collecting wild honey and setting snares for bush meat. It got him thinking about the people-wildlife relationship.
Elsewhere in the Eastern Highlands Doug found Blue gum afforestation encroaching on the high altitude grassland habitat of the beautiful Blue Swallow (the rarest bird in Southern Africa).
Blue gums are also a hazard for Bat Hawks, which insist upon nesting in the trees but lose the nest off the angular and spindly branches in the first stiff breeze.
And upland marshes of the area, the only habitat of the very rare and rarely seen Marsh Tchagra (or shrike) are, every year, pumped dry for plantations and then burnt to stimulate new growth. Yet there is little international pressure for conservation in these places, because they lack the large animals that are the focus of conservation in Africa.
A very different example is Hwange National Park in the west of the country. Originally the area was thinly populated and had little wildlife. However, with colonial settler expansion, Africans were expelled from the fertile midlands and forced to move further west, meeting the wildlife as they moved.
Hwange is now a major tourist destination, and most come to view elephants. To make sure they do, ground water is mechanically pumped to attract animals throughout the year. There are now elephants in their tens of thousands beyond the natural carrying capacity of the park.
The vegetation around the waterholes becomes degraded from trampling and grassland is replaced with acacia woodland. As a result, species like the Crowned Crane are becoming increasingly rare. Even Guineafowl, Red-crested Korhaan and Saddle-billed Storks are suffering, while common species like the Lilac-breasted Roller and Pied Babbler are becoming increasingly common as acacia woodland expands.
The Matopos or Matobo Hills are a spectacular granite area of permanent water with a long history of human habitation. The area is famous for the rock art of the Bushmen who were supplanted by the Bantu Africans. Cecil Rhodes was buried here following colonial edict expelling the maize growing populace from the area to secure it for commercial farming.
During the civil war that culminated in an independent Zimbabwe in 1980, the rocky redoubts of the Matopos were as attractive to guerilla fighters as they were to the African Black Eagle. The people have gone but the Matopos remains a stronghold of the eagle.
This species preys mainly on rock hyrax or dassie. Inside the national park droughts have depressed the rock hyrax population, so groups of juvenile eagles are forced to move from the park to overpopulated and degraded communal lands, home to those whose forebears were forcibly removed from the park. Out here the eagles compete with the people for hyrax caught as bush meat and are accused of taking young goats which are a source of income for these very poor communities. The birds, in the main, either starve or are shot.
Because the adult birds are very long lived and highly territorial, the failure of younger birds to return to fill the gaps in territory in the park left by the death of old birds was hardly noticed. Now it may be almost too late.
Doug speculated that the existence of the park as a place free of people may have contributed to the decline of the species and that the eagles would have been better off if the people had not left and had learnt to respect them in an environment they once both shared.
The Afrikaans word 'vlei' describes shallow, ephemerally wet grasslands which once ringed Zimbabwe's capital.
They are gradually being built over with concrete housing and industrial development. The birds in Doug's home garden were examples of 'new arrivals' which had followed urban development and the planting out of the city. Where once there had been grass now there were groves of eucalypts home to thousands of nesting Cattle Egrets, Sacred Ibis, Black-necked Storks and cormorants.
Down on the vleis people still continue to harvest thatch grass, hundreds of thousands of migratory Yellow Wagtails still fall to earth in the tall reeds and Marsh Owl can still be flushed from grass clumps. After the reaping comes the burning, and Capped Wheatears appear in their thousands to feed off the bounty of insects exposed by the fires.
But these activities are frowned upon by officialdom which is transfixed by the image of a modern 'concrete' western city. So the vleis gradually disappear, and with them a fascinating and increasingly threatened ecology. None is conserved in a reserve system.
Doug concluded by saying that the parks network in Southern Africa is very large and impressive but it does not and cannot cover every ecosystem. Many remain vulnerable and the alienation of people from them in the past has largely contributed to their present vulnerability.
Tourists in search of megafauna are not good advocates for vulnerable ecosystems. Where people have been alienated from traditional lands by the creation of national parks, for whatever reason, resentments simmer, and in countries under severe population pressure, such as Malawi, they are reclaiming the reserves they were once excluded from.
The challenge now is to manage an ecology which includes people.
Thanks to Philip Veerman for overcoming a range of technical obstacles to give us a very thorough rundown of how to identify the two Australian harriers, Circus assimilis, the Spotted Harrier, and Circus approximans, the Swamp Harrier.
Often you will first notice harriers as they track low to the ground first one way, then back, with upswept wings, a fanned tail and slow wingbeats. Closer up the facial disc and very long legs are obvious. Square-tailed kites also usually have upswept wings but hunt over the treetops, not in the open like harriers. Brown Falcons are smaller and have pointed wings and a different flight action.
In flight Swamp Harriers are immediately distinguishable from Spotted Harriers by the white rump. The most obvious features of Spotted Harriers are the chestnut underparts with white spotting. The juveniles can be confused with the adult Swamp Harrier but the spots on the forearm of the young Spotted Harrier are diagnostic. The two species also exhibit different nesting preferences, with Spotted Harriers nesting in trees, Swamp Harriers on the ground.
For further information Philip recommended Birds of Prey by Stephen Debus (available at the shopfront or at meetings for $16.50).
In the main talk of the evening Tony Howard explained how birds' hearing differs from ours, and used sonagrams of calls of a wide range of species, especially of cuckoos and nightbirds, to show how sonagrams can help us understand bird calls.
Birds produce sound from an organ called the syrinx, which is located at the lower end of the trachea, where it joins the two bronchi. (In humans sound is produced in the larynx at the top of the trachea). Most bird species are physically capable of producing two sounds simultaneously.
We can hear pitch as well as birds, but birds are very much better (at least 10 times better) at discriminating detail in a rapidly changing call. To hear the sort of detail that birds can hear we need to hear the call played at a slower speed.
Birds use sound to communicate; echolocating birds also use it to find their way to nests in dark caves. It appears that King Penguins, which have no fixed nest but carry their single egg on their feet, make use of the beat between calls of similar pitch produced by their two voices, to make a call distinctive from the thousands of other birds in the colony. White-rumped Swiflets use clicks for echolocation; the double-clicks they produce would be very suitable for estimating changing distances between bird and target using the Doppler shift.
Production of sonagrams ('sonagram' is a contraction of 'sound spectrogram') used to require expensive equipment, but these days they can easily be produced from a sound recorded into a computer. Sonagrams show pitch (vertical axis) versus time (horizontal axis), the trace becoming darker with greater loudness. Please note that the sonagrams shown here have differing time scales.
The whipbird sonagram shows an antiphonal call, where the male gives a long whistle, almost unchanging in pitch, followed by the ascending whip-crack. The female answers with two descending chee calls.
Spring means that cuckoos are calling, and the remaining sonograms show the most frequently heard calls of three species: the ascending scale call of the Pallid Cuckoo, the trill of the Fan-tailed Cuckoo, and the decending whistle of the Horsfield's Bronze-Cuckoo.
In a wide-ranging talk about 19th century ornithologists, Robert Willson gave us a most interesting account of some early biologists and their association with Australia.
Apparently seasickness forced Charles Darwin to spend as much time as possible on land, to the great benefit of biology in general and ornithology in particular.
Following his voyages in South America and the Galapagos, Darwin spent a few weeks in Australia in 1836, visiting the Blue Mountains, Bathurst, Hobart and Albany (but not Darwin!). Soon after, he retired to his home in the south of England, where he slowly developed his ideas but was reluctant to publish them because he realised how controversial they would be. As an interesting footnote, Robert told us that John Gould did much of the work in classifying Darwin's specimens.
Alfred Russel Wallace came from a less privileged background than Darwin. He spent several years in South America, amassing a large collection of animals that he planned to sell on his return to England. Unfortunately for him, the entire collection was lost when the ship they were on caught fire. Wallace himself barely escaped but he was soon on his way to the Indonesian region. He recognised the distinct boundary between Asian and Australian faunas, and like Darwin he began to speculate on the origin of species, arriving at very similar conclusions. In 1858 Wallace outlined these ideas in a letter to Darwin, prompting Darwin to publish his work quickly.
Jack Holland has lived in Chapman next to Cooleman Ridge Nature Park since 1977. At the August meeting he described how the numbers of Satin Bowerbirds in his garden have changed since then. Bruce Lindenmayer reports.
Jack saw only one bird from 1977 to 1987, but the numbers have since increased sporadically. Initially only green birds were seen, and during the colder months.
He recorded the first bower in 1990 and the first black male bird in 1993. Since 1993, summer records have been common, and currently the Satin Bowerbird is a common bird on his Garden Bird Survey chart.
Subsequent discussion confirmed the presence of bowerbirds in Kambah, in other suburbs in Weston Creek, and in Woden and South Canberra, with bowers in Kambah and Pearce.
Jack said that despite careful observations over the years, he is still unable to distinguish young males from females.
And Jack writes:
I would be interested to know of sightings of Satin Bowerbirds outside the Weston Creek area, including dates and approximate numbers. From the feedback at the meeting it seems they have reached at least the area bounded by Weston Park on Lake Burley Griffin, Griffith, Farrer Ridge and Kambah, and any sightings outside this rough boundary would be particularly appreciated. I would also be grateful for information on the presence of bowers in suburbs outside Weston Creek.
Please send information by fax (6274 1610)
Or call Jack on 6274 1643 (W) or 6288 7840 (H) or email him at jholland@ea.gov.au.
At the August meeting Jenny Bounds spoke about the new COG woodland survey and Paul Fennell told us about the Birds Australia Atlas. Bruce Lindenmayer reports.
COG is ACT region coordinator for the forthcoming Birds Australia Atlas. This is a four year study in which COG members are invited to participate by filling in the blue form circulated with the August Gang-gang. COG has a four-page brochure that gives details of the survey methods and other useful hints. These and survey sheets can be obtained at meetings, from Paul Fennell or Malcolm Fyfe or at the shopfront.
And a note from the committee: Don't be shy about volunteering for the atlas. COG will teach you what to do in some workshops in the next couple of months. All members can help in some way.
The woodland survey is timely because the ACT Government is about to release draft action plans for protection of grassy lowland woodlands and for several threatened or endangered woodland birds. Woodlands with predominantly Yellow Box and Blakely's Red Gum once covered much of the northern ACT, but have now been largely cleared or fragmented.
The ACT Government has funded COG for the first year of the study. COG will seek carry-on funding for subsequent years of the project.
The surveys will be undertaken quarterly, and you are welcome to join if you have some expertise in bird recognition.
Anthony Overs is project coordinator. Please contact him or another site leader if you want to take part in the survey.
- Symonston: Geoffrey Dabb (6295 3449)
- Red Hill: Harvey Perkins (6231 8209)
- Gooroo (south-east of Mulligans Flat): Nicki Taws (6251 1879)
- Mulligans Flat: Jenny Bounds (6288 7802)
- Castle Hill: David McDonald (6231 8904)
- Mount Majura: Anthony Overs (6247 5053)
At this meeting Tony Saunders gave us some good tips for creating a bird-friendly garden:
Terry said that hybrid grevilleas in particular attract large honeyeaters such as Red Wattlebirds, which deter other honeyeaters.
Philip Veerman described the Garden Bird Survey (GBS) in which observers record the maximum number of birds of each species observed at any one time each week in a 100-metre radius around their house. This provides important long-term data on the local environment. We are now on the fourth (greatly improved) version of the chart. Philip was able to present data onto the screen, direct from the computer database. This now holds all but the first two years of the count results, along with the last six years of the breeding records. For years 3 to 16 there are over 37,000 records involving 217 species. There are over 900 observer-years of data for 231 sites; eight sites have been going for 16 years. Breeding data for years 10 to 16 comprise 1355 records for 67 species. Information can be provided on all or selected records of any combination of species and/or localities. Contributors can get a print-out of all their records. The more data there are the more useful the results will be. Top priorities now are (a) for people who surveyed several years ago, then stopped, to resume their participation and (b) to attract new participants, especially in the outer suburbs. If anyone has a chart from any year that was not submitted, please do so: the data previously released in the annual bird reports are being recalculated on a much improved system. Participating in the GBS is fun, easy and a great learning experience; it does not take long so please help with this important project. Charts are available at meetings or from the shopfront (but not from Philip) so get one soon.
In the main talk of the evening Geoff Dabb took us to the South Pacific. His talk on the birds of Tonga ranged from speculation on which bird would be the first to see in the new millenium (Tonga is only just west of the international dateline) to hand-outs of chocolate bars for correctly identifying the connection between Tonga and the word 'bounty'! Geoff's talk focused on Tongatapu, the main island of Tonga, a 'Makatea island' (uplifted atoll) - about seven times the area of Norfolk Island and at about the same latitude as Mackay. The capital, Nuku'alofa, is on the northern side. The island is now mainly under cultivation for coconuts and other food plants.
Tonga has relatively few birds - 15 seabirds, 17 other non-passerines and five passerines. There is a megapode on a more northern island that lays its eggs in burrows in volcanic ash near the rim of an active crater. There are no endemic southern Tongan species but three species (the Red Shining Parrot Prosopeia tabuensis, the Spotless Crake Porzana tabuensis and the Polynesian Starling Aplonis tabuensis) take their names from the latinised form of 'of Tongatabu'. Typical island species include the Polynesian triller Lalage maculosa, the Red-vented bulbul Pycnonotus cafer (introduced from India via Fiji), two Ptilinopus fruit doves, the Wattled Honeyeater Foulehaio carunculata, the Reef Heron and the Wandering Tattler. There are introduced Eurasian Starlings on Tongatapu but they do not extend further north, demonstrating the inability of this otherwise successful invader to penetrate far into the tropics. Like most tropical Pacific islands, Tongatapu has one kind of kingfisher, usually easily observed by visitors. The central Pacific birds have long been assumed to be Halycon (now Todirhamphus) chloris, the Collared or Mangrove Kingfisher, but, because of more buffy underparts, there has been recent speculation that the birds of nearby Fiji are a form of T. sacra, the Sacred Kingfisher. This has raised doubts about the relationships of all the Pacific Kingfishers.
The short talk for the evening was by Bruce Lindenmayer in his role of one of COG's representatives on the Conservation Council of the South-East Region and Canberra. This umbrella organisation represents about 35 community groups such as COG, the Society for Growing Australian Plants, ACT Field Naturalists, the Wilderness Society, NPWS, etc. and is one of the main voices on conservation issues in the region. Issues of relevance to the ACT that the Conservation Council is currently involved with include the Nature Conservation Strategy and Action Plans, the John Dedman Parkway, Horse and mountain bike access to Canberra Nature Park, Landcare, Roadside Vegetation, Weed Strategy and Action Plan, the Red Hill Golf Club housing development proposal, Sustainable Transport, Cats etc.
The new director of the Council, Rupert MacGreggor, followed Bruce with an outline of his views of the role and direction the council should be taking in the coming years. He emphasised the need for greater diplomacy and involvement in government decision-making processes, and to avoid confrontationist approaches which might hinder desireable end results. Unfortunately, the excellent and vital work of the council is always constrained by physical and financial duress. If you have any expertise, time or money to spare, please don't hesitate to contact the COG president.
The main speaker for the evening was Peter Fullagar who gave a marathon talk on his visit to southern Patagonia in South America 18 months ago. Biologically, South America is a fascinating and awe-inspiring place, with a third of the world's bird species being present. Although Patagonia, at the southern tip of the continent, cannot boast the incredible number and variety of species that Colombia, Peru, Brazil and Ecuador do (about 1700 species), there are still close to 1000 species in Argentina and Chile representing about 80 of the 92 families in South America, including six of the nine endemic families. Specialties include the tinamous, rheas, various grebes, flamingoes, seed-snipe, sheathbills, hummingbirds, ovenbirds, tapaculos, tyrant-flycatchers, plant-cutters, many finch groups, seabirds, and of course ducks - which I think might have been one of Peter's main reasons for going!
Even in summer, the conditions at the southern tip of South America are rather cool, a fact that was clearly demonstrated in the slides, of both the birds and the scenery, that Peter showed. These included a number in and around the Beagle Passage (of Charles Darwin fame) in Tierra del Fuego, as well as the mainland to the north and several places further up the Chilean coast. Various glaciers and alpine scenery, fast flowing mountain streams and placid glacial lakes, extensive grassy plains and Araucaria and Nothofagus beech forest spring to mind.
Of the birds, the Kelp Geese, Brown-hooded Gull, Magellanic Penguin, steamer ducks, Magellanic and Ashy-headed Geese, rheas, Chilean Flamingo, Black-headed Duck (also known as the Cuckoo Duck, this is the only obligate parasitic duck in the world, laying its eggs in a range of other species' nests), Black-necked Swan and Crested Caracara were memorable. A late evening, but well worth the glimpse of another continent with all the variety and uniqueness that South America has to offer.
Harvey Perkins
The meeting opened with the AGM. The President's report and financial statements were accepted and the following people elected to the committee: Paul Fennell (President), Jenny Bounds (Vice-President), Susan Newbery (Secretary), John Avery (Treasurer), Malcolm Fyfe, Sue Mathews, Carol McLeay, David Landon and David McDonald. Paul Fennell outlined some recent activities of subcommittees.
Following the AGM, Jenny Bounds outlined some exciting field trips coming up - to the Bunya Mountains with Environment Tours in May 1998, to the Wet Tropics with Environment Tours in May 1999 and to South Africa in September 1999. See Field Trip page for further details. Jenny also described how the field trip program is prepared, starting in July-August with the preparation of a draft program for the next calendar year. Your suggestions are always welcome, especially if you can lead the tour you suggest! Malcolm Fyfe then provided some information on record collection. There is a new COG data sheet that follows the Christidis and Boles listing, and records are being added to the database as quickly as possible. All unusual sightings are put into the database, though a special notation will be made to indicate endorsement by the Rarities Panel.
Professor Henry Nix gave the main talk of the evening. He described a long-term CSIRO-CRES experiment to examine changes in eucalypt 'islands' left when eucalypt forest was cleared and planted with pines. The experiment has been carried out for 14 years near Wog Wog Mountain. The site was on a fairly gentle slope with a relatively warm, wet climate. Acacia allata grew along the creeks with manna gum E. viminalis, while narrowleaf peppermint and stringybark were the dominant species on the drier ridges. The canopy was 20-30 m high. There had been little disturbance in about 80 years. The area was selected in 1984 and was sampled before clearing and in each subsequent year. Two control plots were selected in forest that was not to be logged. Four sets of plots were selected in the area to be cleared. Each set of plots comprised one 1/4 ha plot, one 1 ha plot and one 3 ha plot.
Birds living in the shrub and litter layer quickly declined after clearing, as the exposed understorey died out. The canopy birds hung on well after clearing, though some return when the pines get taller and presumably less exposed in the island. The plots were surveyed in the first week in November each year, the time of peak spring growth, when there are the greatest numbers of breeding birds and of migrants. Initially each plot contained about 13 species, and the control plots still have about this number of species. However, both the number of species and the number of individuals were roughly halved in the island plots after clearing. The canopy birds (mainly Yellow-faced Honeyeaters, White-naped Honeyeaters, and White-eared Honeyeaters), steadily declined in numbers although the number of species declined less rapidly. Henry stressed the importance of long-term studies like this to our understanding of local ecology.
WOODSWALLOWS AND BIOGEOGRAPHY
Geoff Dabb and Dick Schodde delighted the March meeting with their respective accounts of woodswallows and of survey work with important consequences for conservation.
Geoff Dabb opened with a brief run-down on woodswallows. Named for a supposed resemblance to Old World shrikes (Artamus, meaning 'butcher', is the Greek for the Latin Lanius, a genus of shrikes), the family Artamidae comprises the woodswallows, butcherbirds, currawongs and magpies. The woodswallow group itself has 11 members, in Australia, Papua New Guinea and South-east Asia. Of the six woodswallows found in Australia, four are confined to Australia while two (White-breasted and Black-faced) extend beyond. The Dusky has the smallest range though it is the best known to many people because of its distribution near population centres in south-eastern Australia. The Black-faced has the largest range. The White-browed and Masked Woodswallows are highly nomadic and often occur together, while the White-breasted and Little tend to occur in the north. In Canberra, the Dusky is a common summer breeding visitor, tending to occur at vegetation boundaries. Irruptions of White-browed occur in the ACT every few years, especially around November, probably associated with drought conditions to the west. Geoff accompanied his talk with many wonderful slides illustrating local nesting and feeding habits.
In the main talk Dick Schodde outlined a CSIRO project to compile an inventory of geographical bird forms in Australia and to verify regional units. The inventory is based on surveys in key geographical areas influenced by apparent biogeographical barriers. Four of these areas are the Eyre Basin (Cooper-Diamantina river systems and Lake Eyre), the Murray-Darling Basin, the Eyre Peninsula, Gawler Ranges and Flinders Ranges, and Melville Island, where Dick had undertaken recent trips. For the inventory, detailed plumage characteristics are used to define local populations more precisely than has previously been achieved. As a result, it is expected that 1500-2000 bird forms will be recognised in Australia.
Dick referred particularly to work in the Eyre Basin and the Flinders Ranges, illustrating his points by reference to many species. Here are just a few examples. The Splendid Fairy-wren has been thought to comprise three subspecies, occurring in WA, Central Australia and the Murray-Darling Basin. The CSIRO survey has shown that there is a fourth, pale sky blue subspecies at the top of the Cooper Basin. Similarly the Black-chinned Honeyeater has a golden-backed form in the west and a duller eastern form. The survey has identified an isolated intergrading population near Thargomindah. The hypothesis is that the Grey Range, which forms the watershed between the Eyre Basin and the Murray-Darling Basin, operates as a barrier to sedentary birds, giving rise to differentiation between populations on either side so that many forms previously thought to be the same are actually different. And in the Flinders Ranges, which is the eastern edge of the Eyrean barrier between western and eastern faunal regions, the survey has identified a distinct endemic form of the Striated Grasswren (which will probably prove to be a new species) and also a White-browed Treecreeper that has characteristics of both the eastern and western forms.
The results of the survey will be published later this year. An important consequence of the recognition of so many new forms will be that the conservation status of many groups will now need to be reassessed, to take account of the many more distinct populations that have been discovered.
Dick Schodde was also our short talk presenter at the February meeting on the subject of why birds evolved feathers. These days feathers fulfil a number of purposes including flight, warmth, and camouflage and display. Current opinion, however, is that feathers originally evolved as a means of maintaining body temperature - modern birds have a body temperature of about 4loC - and the other functions developed subsequently. Feathers can be divided into four main functional and structural groups, these being flight feathers, contour feathers, down, and powder down. Contour feathers provide streamlining for flight as well as waterproofing, down provides warmth, and powder down, for the relatively few birds that have it (including cockatoos, herons, woodswallows and cuckoo-shrikes) is used for waterproofing instead of the more typical oiling of feathers with oil from the preening gland at the base of the tail. But it is the colouration of feathers for camouflage or display purposes, by either pigmentation or structural colours, that produces the amazing beauty and variety of colours that is so appealing to all birdwatchers.
The main talk was given by Alan Cowan, with botanical assistance from Des Clark-Walker, on their adventures during a recent trip around the New Zealand sub-antarctic Islands (Snares, Auckland, Campbell, Antipodes, Bounty and Chatham's) and Macquarie Island. Alan was a contributor to HANZAB on seabirds and we were fortunate to have the benefit of his expertise. All of the New Zealand Islands were discovered in the 1800s and spawned early sealing and some whaling industries before some aborted attempts at farming in the early 1900s. All islands and most of the Chatham Is group are now nature reserves and have been since the 1930s. Alan discussed an enviable number and variety of birds (and mammals and plants) including many of the endemics such as Snares Crested Penguin, Auckland Island Shag, Auckland Island Flightless Teal, Red-crowned Parakeet and Shore Plover, as well as a number of endemic sub-species.
Our thanks once again to Dick, and also to Alan and Des for a glimpse of an environment and experience that most of us will only ever get to read or dream about.
The January meeting - "Members' Night" - was a great success with a variety of presentations by members. David Pfanner shared several of his more memorable recent birding experiences in the 'Red Centre' in the form of poetry put to music on his soprano recorder; Steve Wilson talked about his and Noni's recent trip to Far North Queensland and the wonderful ecotourism opportunities there are up that way; Steve Stephinson, assisted by Helen Stephinson and Lyn Scrymgeour, talked about the recent COG trip to Lady Musgrave Island; Richard Jordan discussed a forthcoming EMU TOURS - COG trip to outback NSW and South Australia and what you might expect or hope to see on the trip; Chris Bellamy talked about his experiences of 'global birding' at a huge bird park in Germany; and Jenny Bounds described her experiences on the recent COG trip to south-west Queensland with Environment Tours where the highlights included Gibberbird, Black-breasted Buzzard, Orange Chat, Spinifex Pigeon and Hall's Babbler.
Thankyou to all the speakers.