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Dick Schodde was host of the Christmas Party at the CSIRO National Wildlife Collection at Gunghalin in December. Dick will be retiring during the year, so this will be his last time in this role. COG thanks Dick very much for his generosity and enthusiasm in sharing his knowledge over the years and wish him well.
Dick began by telling us of two egg collections that have recently been donated to the Wildlife Collection. The first was Gordon Ragless's collection focusing on Mount Lofty and the nearby mallee. The second was Robert Green's collection of eggs of Tasmanian birds, which is accompanied by very comprehensive data.
Dick then took us on a trip to southwestern Western Australia, where he had recently studied the bird fauna. He began by identifying three habitats in the area - in the west jarra-karri on laterite hillsides, in the east mallee (mostly now cleared and saline) and in between wandoo, the equivalent to Yellow Box woodland in southeastern Australia. He talked about geographical variation in ringnecks and rosellas, stressing that differentiating birds by species is no longer a useful concept for conservation. You can read more about these concepts in the new book by Dick and Ian Mason called The directory of Australian Birds.
Jamie Matthew followed Dick with an interesting talk on scrubwrens, Sericornis. He used a series of skins to illustrate geographic variation in the Large-billed Scrubwren and showed how some characteristics resemble the Tropical Scrubwrenalso show that the Largenorthern subspeciesdistribution of rainforest. These similarities are also reflected in molecular biology studies, which -billed Scrubwren from the southeastern part of the species' range is just as closely related to the Tropical Scrubwren as the more . This suggest that the link is a very old one and Jamie speculated that the current distribution is probably related to past changes in the distribution of rainforest.
Sue Mathews
Thanks to Nicki Taws and Alan Morris for their informative presentations and for helping to create such an enjoyable evening. David Landon reports.
Nicki Taws started by telling us about the early names given to this attractive bird, such as Diamond Finch, Diamond Sparrow, and the one preferred by Gould, the Spotted-sided Finch.
A number of slides were shown and we could clearly see the slight differences between the sexes, principally the female's narrower breast band. The immature is generally browner, with an indistinct breast band, and the spots on the flanks appear more like barring. It is about a year before the bill turns red.
Diamond Firetails are gregarious birds, frequently found in flocks, and sometimes nesting in colonies. It is possible that many mate for life. Nicki talked about the delightful courting ritual and described the nests of these birds, adding that Gould once found one in the base of a 'whistling-eagle' nest.
Nicki told us that Diamond Firetails are seed-eating birds, usually found on the ground, and have adapted very well to exotic plants, but sadly they appear to be in decline, presumably because of loss of habitat. However, the question can still be asked: If they enjoy exotic seeds so much, why are they still so uncommon? Anyway, your best chance of seeing these birds in the ACT would be a visit to Mulligans Flat, Castle Hill or Newline Quarry.
Alan Morris is a district manager with the New South Wales National Parks and Wildlife Service. He told us about changes in the bird population of Lord Howe Island over 25 years. Lord Howe is a tropical island complete with coral reefs and lagoons. Alan made three trips there in 1971, each time by Sunderland flying boat because there was no airport in those days. And if the seas were rough, your departure was delayed and you had to spend more time on this tropical island - hard life!
In 1971 Alan principally studied the Providence Petrel and the Lord Howe Woodhen, the latter taking up most of his time. For up to 14 days, he and his colleagues would camp on the very top of Mount Gower, which was the only place that the feral goats and pigs could not reach. There were only 8-10 woodhen territories at that time, but when he returned in 1996 this flightless bird was to be found over most of the island. This great success story was the result of recommendations he made which led to an improved environment for all the island's birds. This culminated in the whole island being declared a national park in the early 1980s, resulting eventually in the eradication of the feral cats and pigs, and the goats being brought under control. It also helped that the woodhen was successfully bred in captivity, and today the population is 180-210.
The Providence Petrel was always well established on Lord Howe Island and the numbers today are about the same as in 1971. Alan described how these birds have developed an extraordinary technique, crude but effective, for getting to their burrows: they simply crash land onto the thick canopy of the tropical trees, sort of fly/flop down to the ground and then walk/waddle to their nests. And the reverse process? They find a suitable tree-fern, then climb/fly up it and, as soon as they are above the canopy, take off from the tree-fern -easy!
Other petrels, as well as shearwaters, boobies, tropicbirds, terns and noddies, are well established on Lord Howe Island. So, too, are a number of birds well known to us: kestrels, Golden Whistlers, Buff-banded Rails (none in 1971, plenty today), Mallards, Masked Lapwings, White-faced Herons, Purple Swamphens, Emerald Doves, Magpie-Larks, Song Thrushes and Blackbirds.
The only problem at the moment is the Masked Owl, which was imported in the belief that it would get rid of some of the island's rats. However, the owl decided it preferred White Terns, with the result that some people reckon it must be eliminated and the only way to do that is to shoot it. After all, this owl is exotic, we were assured.
In the first talk of the evening, Julian Reid told us a worrying story about the decline of the Jacky Winter in the sheep-wheat belt of New South Wales. He suggested that the decline is symptomatic of a wider crisis affecting a range of `woodland' birds. Most are sedentary, ground-feeding, insectivorous species, and the Hooded Robin is perhaps the worst affected. Many have been quite widely distributed but have apparently always been absent from large islands, such as Kangaroo Island and Tasmania, and have disappeared quite early in the establishment of cities. Julian said that chemicals could not be dismissed as a possible cause of disappearance, but that habitat clearance and then degradation of the remnants (eg through grazing or collection of firewood) and lagged habitat fragmentation effects are probably more important.
Sandy Gilmore described the use of habitat modelling to try to answer this question for some ground-dwelling birds in northeastern New South Wales. He surveyed bird numbers by taping their calls in the hour before dawn, allowing him to estimate both how many birds there were and (by the intensity of the call) how far away they were. The birds had a real routine, with each species having a particular `window' of time in which they called (orchestrated to the minute!!). This method allows many sites to be surveyed at the same time and eliminates differences in observer competence. Sandy suggested that it would be very appropriate for future atlas surveys.
Many variables were analysed during the study. The initial hypothesis was that productivity would be an important factor limiting bird distribution, and this was the case for lyrebirds and some other species, but not for all species. For example, Noisy Pitta distribution appears to be correlated with calcium levels, presumably related to the presence of snails. Lyrebird distribution showed a correlation with higher temperatures and larger trees but not with rainfall, soil nutrients, soil depth or forest productivity. Sandy reminded people to be aware of the amount of litter underfoot (this is the main qualitative indicator of productivity) because it forms the basis of the food chain.
Nicki Taws and Alison Rowell gave us an update on the atlas and woodland surveys, respectively.
Thanks to Dick Schodde for an illuminating talk on local cuckoos and to Jim Wilson for an account of high adventure and a real detective story on wader migration.
Australia and Papua New Guinea have the most diverse group of parasitic cuckoos in the world and seven of them are found in COG's area of interest: two bronze-cuckoos, two fan-tailed cuckoos, the Pallid Cuckoo, the Koel and the Channel-billed Cuckoo. They all parasitise the nests of other birds. Superficially, cuckoos can look a bit like passerines, but they can easily be distinguished by the barring underneath their tails and by their feet, which have two toes pointing forward and two behind. Most are fairly easily identified by their calls, the most prominent of which are made by males to define their territories and signal to females that they are available. Most adults are also fairly easily identified by their plumage though it is not always possible to tell the sexes apart. Juveniles can present a problem but can usually be distinguished by carefully looking at the back.
Jim Wilson gave us an amazing account of his adventures in the Gulf of Carpentaria and in the Yellow Sea of China - braving crocodiles, mosquitoes and mud, all in the name of wader research.
In the 1980s surveys conducted from Customs aircraft found that 80% of the waders using the Gulf occur in the southeastern corner, within 100 km north and west of Karumba. This area was chosen as a study site by Peter Driscoll, who was allocated funds from the Natural Heritage Trust to find out more about the waders using the Gulf. Jim showed slides of the Gulf as seen from Peter's microlight. The microlight, boat and an all-terraine ARGO were used to reach the otherwise inaccessible Gulf shores to count the waders. Most of these birds were Great Knots, Red Knots and Black-tailed Godwits.
We know that many species which spend the non-breeding season in Australia breed in Siberia and Alaska, but how do they get there?
It is known that larger species such as Great Knot, Red Knot and Bar-tailed Godwit fly 5000-6000 km direct to the coasts of South Korea and east China. By looking at the dates of banding recoveries, flag sightings and counts there, Jim and his colleagues discovered that during May the birds went "missing". Maps in the National Library indicated that the largest mudflats in the world lay on the northern shores of the Yellow Sea, in areas never visited by wader experts. The distance from there to the breeding grounds is 3000-5000 km, similar to distances known in other parts of the world from places used as the last staging area, before the last flight. Jim and his colleagues concluded that the missing birds were using this unexplored area in May.
With funds from Environment Australia, Wetlands International supported Mark Barter and Jim to run training courses on the Nature Reserves on these coasts in 1998 and 1999. They discovered that the theory was true and counted 260,000 waders. One site was probably one of the world's top wader sites. Here they found 50,000 Bar-tailed Godwits and believe this to be the last staging post for eastern Australian and New Zealand birds on their way to Alaska. Jim slowed slides of the threats to these birds in China from land reclamation, overfishing of shell foods and oil extraction.
The Australasian Wader Studies Group is often looking for volunteers to help in its field work to learn more about these birds and can be contacted on 6295 2528 (see also box below).
Thanks to Peter Fullagar and Jack Holland for writing the following accounts of their respective talks.
Catastrophic events in a seabird colony
Rarely does it happen that extreme events in the life histories of birds are actually measured. From a longstanding study of seabirds at Montagu Island two examples of very low annual breeding success have been witnessed. The explanation for these disasters was conclusively determined the second time it happened. Peter Fullagar described the study of shearwater populations breeding on Montagu Island and talked about the catastrophic events and several other aspects of this long-term study, now in its 40th year.
Three species of shearwater breed on Montagu Island: Short-tailed Shearwaters Puffinus pacificus, Wedge-tailed Shearwaters P. pacificus and Sooty Shearwaters P. griseus. In total the colonies occupy about 7 ha, mainly on the northern portion of the island, and breeding densities of successfully reared chicks reach as high as 2500 per hectare, in a very good season. This means that in many years the island's population of shearwaters produces 15,000 or more young birds at the time they fledge in April.
Annual surveys of the numbers of chicks present within fixed plots have been conducted on Montagu Island since 1960. These surveys have revealed much about the long-term dynamics of the shearwaters breeding on the island. For example, we have seen a trend showing an increasing proportion of Wedge-tailed Shearwaters in the population with the consequent decrease in the proportion of Short-tailed and Sooty Shearwaters.
Recently, in collaboration with students from Charles Sturt University, more detailed studies have been set up to examine certain aspects of the chick provisioning activities of shearwaters on the island. These studies have revealed that breeding adults of the Short-tailed Shearwater make round trips from Montagu Island to as far as the Antarctic ice edge when gathering food for the chick. In 1971 and again in 1999 catastrophic failures in the survival of chicks were measured. From additional studies at the critical times we now know that very high rainfall on the island at hatching, and for a period in the early life of the chicks, can cause these failures. Many eggs are abandoned by sitting adults when extreme rainfall events flood burrows, and small chicks are particularly vulnerable to drowning or becoming crushed if their burrows collapse.
In his talk on the crakes of the local area, Jack Holland noted that these species are easily overlooked as they live among the reeds at the swamp margins and are relatively shy, though they do come out to feed on muddy patches if not disturbed. To see crakes you basically need to know where to look, make a dedicated effort and use special techniques. You are very unlikely to encounter them on the average day of woodland birding. However, if conditions/water levels are right, you stand a good chance of being rewarded. Jack pointed out that finding crakes is often the hardest part; identification is relatively easy as long as you are prepared to be still and patient, letting the birds come to you.
Using some illustrative slides, Jack pointed out the diagnostic features of the three local species (Australian, Baillon's and Spotless Crakes), emphasising that detailed plumage descriptions are not usually required for adequate identification. Then, with a further series of slides of birds in some more typical field situations, Jack tested members on what they had learnt, interposing information about the situations in which he had encountered the species in the 17 years since the RAOU Atlas ended, and noting that in his 5 years of active participation in that project he had encountered only one crake, which at the time he was not able to properly identify.
'smug birds that look rather like a superior head waiter in an expensive restaurant'
Thanks to Geoff Dabb for entertaining us with another wonderfully erudite and witty talk. This time it enjoyed the splendid title 'Bustards - an armchair chat richly loaded with personal anecdotes, name dropping, obscure geographical allusions, and other trivia'.
Geoff concentrated on three of the largest bustards (Great, Kori and Australian). Sometimes these have been placed in the same species, but they have very different displays. Various photos and illustrations illustrated Geoff's contention that bustards are 'smug birds that look rather like a superior head waiter in an expensive restaurant'! They do not look quite so smug in flight though, perhaps because the larger species are close to the maximum theoretical flying weight. The word 'bustard' is said to come from the name used by the Romans, Avis tarda.
In Australia, bustards were first recorded by Captain Cook in 1770 near Bundaberg. Like many subsequent observers, he shot one and commented on how tasty it was! In 1855 John Gale reported them near the present day Parliament House in Canberra. They are still one of Australia's most widespread birds, particularly in northern Australia, and especially on the Barkly Tableland. There is a small population in southern Papua New Guinea, no doubt derived from Australia and possibly moving between the two countries. Although bustards no longer occur naturally in southeastern Australia, much of our current knowledge about them comes from a captive population at Serendip Sanctuary near Geelong.
Bustards are nomadic and usually occur singly or in pairs or small groups, though males may show lek behaviour. Displays are spectacular and extraordinary, all species showing a lot of white and raising the tail over the back. The Australian species also distends its huge throat sac, spreads its neck feathers and droops its wings.
It is all too easy to overlook interesting behaviour in common species seen every day. Thanks to Michelle Hall from the ANU for providing some interesting insights into Australian Magpie-lark behaviour.
Magpie-larks live in pairs in territories that are defended by both males (with a white eyebrow) and females (with white around the bill) throughout the year. They breed from August to September; both sexes build the nest (usually so high in trees that Michelle had to learn to drive a cherry-picker so that she could carry out her work!) and both incubate the young.
In birds, duetting is the name used when one bird responds in a synchronised way when its partner starts to sing. Often the timing is so precise that it sounds as though only one bird is calling. In the case of duetting Magpie-larks (they may also sing alone), either sex may initiate the duet and they alternate notes so that there is no overlap between the calls of each bird.
Magpie-larks do not seem to use duetting to maintain contact, because most duets occur when the partner is nearby, and anyway they live in quite open habitat where birds would be expected to use sight rather than sound to keep in touch. Males do not seem to use it to prevent females from 'cheating' on them with other males in the breeding season, because males respond less when females are fertile than when they are not and are less likely to initiate the call at these times.
It seems that the main function of duetting in Magpie-larks is territorial defence and communication among neighbours. Birds duetted much more when a tape of a Magpie-lark call was played, and the intensity of the duet was much greater in response to a neighbour in its own territory than to an unknown bird or a neighbour trying to enter the duetting pair's territory.
Michelle has colour-banded a lot of Magpie-larks around the ACT so please look out for banded birds and let her know if you see any.
Thanks to Philip Veerman, Jeff Clyde and Allan Kerr for writing up their own talks this month.
Philip Veerman presented another promotional extravaganza on the COG Garden Bird Survey. The progress made in just one year since his last talk is enormous. For the first time we now have all the count and breeding data for the full 17 years on a computer database. By the time this note is printed, year 18 will have finished and year 19 started. All kinds of things can be done with the assembled data. For example, they show that, on average, for each additional week a site is surveyed in a year a species is added to the chart.
Total numbers of birds have been relatively constant on an annual basis over the years but there have been many interesting changes or trends in individual species. Having more observers in a year increases the number of species recorded but not the number of birds recorded. Winter consistently has the highest number of birds of the four seasons.
The database contains the monthly abundances of all species continuously for 17 years. A total of 216 species have been recorded and 96 were recorded in all 17 years. Philip presented some graphs of overall history of the survey and data for a few species, direct from the computer onto the screen. This material will go into the GBS book to come out late this year.
Philip finished with a brief run-down on what is required of participators and gave tips for contributors. A new version (V5) of the chart with minor changes will be issued soon.
Phillip Island is a 190-ha volcanic island 6 km due south of Norfolk Island. Before European settlement it was probably covered in rainforest. There is no free water on the island and it is very hard to get ashore, so the island has never been settled. However, Phillip Island has not been left alone. Early Norfolk Island settlers killed birds for feathers; they also released pigs, goats and rabbits, with erosion quickly following. Rabbits were eliminated from the island in 1986, but pigs and goats continued their devastation until 1994.
Phillip was declared a forestry reserve in 1938 and became part of the Norfolk Island National Park in 1996. The island is being revegetated through the use of inclusions, seed drops, silt traps and native replantings but, with no water and difficult access, it is a slow process. Moreover, the African olive tree has become a serious pest, with long stretches of impenetrable thickets along the gullies. Fortunately, seabird populations grow under the watchful eyes and care of Norfolk Islanders Owen and Beryl Evans and Environment Australia.
For the birdwatcher, Phillip Island is of great interest as a breeding place for 12 seabirds and as one of the few remaining places in the world where seabird eggs (of the Sooty Tern) can be legally collected during a short open season. Because of the virtual lack of surface water, passerine species are almost absent.
The Sooty Tern, which is the most abundant of all tropical seabirds, is dominant. In 1987, 8,000-10,000 pairs were counted. The beautiful Australasian Gannet nests here, as does the Masked Booby. There are probably more than 400 pairs of the Red-tailed Tropicbird, many nesting. Seeing the tropicbirds soaring and gliding in shining elegance does not prepare the observer for the snapping and noisy attacks they make when disturbed on the nest.
Although wiped out on Norfolk Island in the 1790s, the Providence Petrel has been found nesting on Phillip Island in small numbers. Owen Evans has been banding them for years, along with Little and Wedge-tailed Shearwaters. Both Common and Black Noddies nest on the island, the former on the ground, the latter in remnant patches of trees. The Black-winged Petrel, first recorded in 1792, was found again on the island in 1965. Scraping and scratching noises under the floor of the tent at night were found to be due to one of these petrels digging its burrow. Several Kermadec Petrels were seen, nesting under low shrubs. The beautiful and soft little Grey Ternlet, was plentiful and seen nesting in many places. Its wide-eyed innocence and trust were particularly moving.
Jeff Clyde and Allan Kerr
The new COG rules were adopted at the Special General Meeting held on 12 May. Richard Allan and Henry Nix were the main speakers at the general meeting that followed.
Thanks to Richard Allan for another excellent talk.
There are four species of plumed honeyeaters in New South Wales: the Grey-fronted and Yellow-plumed have a streaked breast; this is absent in White-plumed and indistinct in Fuscous Honeyeaters.
White-plumed have a yellow face and pale grey-green plumage. The white plume does not always show up well. Young birds have a brownish tinge on the back, and a pale beak. In Canberra these birds breed around the lake and are often seen in gardens on the north side. The 'chickowee' call is quite distinctive.
Fuscous Honeyeaters have no yellow on the face, and are smudgy around the eye and lores. The small plume is hard to see in the field. These birds are present mainly in winter and do not breed in Canberra. They tend to come here in dry years, possibly from far afield. In eclipse plumage the beak is pale at the base and black at the tip. Young birds have a pale bill and gape. Jamie Matthew has recently discovered that the alula (the feather above the primary coverts at the bend of the wing) is pointed in adults, rounded in young birds.
Yellow-plumed Honeyeaters are birds of the mallee. They have greenish crowns, with heavy streaking on the breast. Grey-fronted Honeyeaters are named for a grey patch on the forehead. They have a large yellow plume with a black border and mottled streaking on the breast.
Twenty-seven years ago, Henry Nix wrote an article in Canberra Bird Notes suggesting that light intensity plays an important role in determining effective foraging time and hence bird distribution. At the May meeting he speculated further on this interesting topic using myiagrid flycatchers as an example.
There are five species of myiagrid flycatchers in Australia. Restless and Leaden Flycatchers tend to occur in relatively open areas, Satin, Broad-billed and Shining in denser or taller vegetation. When the structure of the vegetation is examined more closely, there seems to be a gradient in order of decreasing light intensity from Restless Flycatcher and Leaden Flycatcher to Satin, Broad-billed and Shining Flycatchers.
This can be quantitatively demonstrated using foliage projection cover (percentage of cover in the tallest stratum) as an indicator of light intensity.
All the Australian myiagrid flycatchers can be found in mangroves (though this is not their normal habitat) and the figure (below) illustrates how the concept of light gradation applies to a mangrove area in North Queensland. Note how the Restless Flycatcher may use a bare branch in the open over water near thick mangroves, even though it would usually be found in more open areas.
We hope we won't have to wait another 27 years for the next instalment of this interesting saga!
There were three talented and knowledgeable women speakers at the April meeting. Nicki Taws started the evening with a timely talk on honeyeater migration, Tonia Cochran spoke about Tasmanian endemics and there was a special last-minute treat - Sonia Tidemann on Gouldian Finches. Thanks to Kay Hahne and Ian Anderson for their comprehensive accounts of these talks.
At the April meeting, Nicki Taws gave us a timely talk on honeyeater migration in the ACT. This phenomenon happens from late March to early May, so is happening right now. Kay Hahne reports on Nicki's talk.
An early recorded reference to this spectacular movement was by Lamm and Calaby in 1949; they recorded 4,000 birds per hour in early April, then 2 weeks later recorded 10,000 birds per hour. In the 1960s, over 28,000 honeyeaters were banded by Steve Wilson and team around the ACT but only 12 were ever recovered. A further 16,000 were banded along the Murrumbidgee but only six were recovered. This did not help much in answering the questions of where the honeyeaters come from and where they are going.
We do know that the Yellow-faced Honeyeater is the most common species, followed by fewer White-naped Honeyeaters in a 50:50 mix about 2 weeks later. Also, Red Wattlebirds migrate in significant numbers, along with a few Fuscous, White-eared, Crescent, Brown-headed and New Holland Honeyeaters and Eastern Spinebills. Even Silvereyes plus Spotted and Striated Pardalotes get caught up in the excitement.
The greatest movement occurs on calm, clear, sunny days and is generally in an easterly direction. The beginning of movement appears to be triggered by the first cold weather in the mountains and/or the unavailability of food.
Nicki had honeyeater survey forms available for those who wished to do some counting, and directed us to good sites along the Murrumbidgee such as Casuarina Sands, Point Hut, Gigerline and Angle Crossing. Tune your ears in for the distinctive 'chip chip chip' of the Yellow-faced and the soft 'mew mew mew' of the White-naped, as often they are too high to see the yellow stripe across the face of the Yellow-faced or the dark head and white breast of the White-naped.
Kay Hahne
Dr Tonia Cochran runs nature tours and provides accommodation for birdwatchers on Bruny Island off the south coast of Tasmania. Her 1800-acre property 'Inala' is home to all 12 endemic birds of Tasmania. Tonia is heavily involved in the recovery programs for the Forty-spotted Pardalote and the Swift Parrot. Tonia gave interesting thumbnail sketches of these birds, together with the Tasmanian subspecies of mainland birds.
Among the endemics, Tonia described the joys and vicissitudes of the breeding cycle of the flightless Tasmanian Native Hen, with its inventive breeding pattern to keep chick production ahead of the drain caused by marauding raptors such as the Grey Goshawk (white morph) and Swamp Harrier. She also introduced us to the Green Rosella, Tasmania's version of the Crimson Rosella.
Dear to Tonia's heart is the highly endangered Forty-spotted Pardalote. This species is endangered because the silly, picky birds prefer to live only in Eucalyptus viminalis! This really restricts their life chances. Tonia is trying to preserve existing habitat and plant new trees, but it takes between 10 and 15 years of solid growth before the 40-Spots take any interest in the young trees. The birds are fussy, too, about the quality of nest hollow they use, and it is important to keep old dead trees for this purpose. 1999 has been a good breeding season, though numbers are low.
The wet ferny gullies of the rainforest on Tonia's property are the preferred habitat of the Tasmanian Scrubwren, which is larger and longer than the White-browed Scrubwren. In similar spots in mid-canopy are the Scrubtit and, not far away, the Tasmanian Thornbill. The latter is like our Brown Thornbill, with some differences in colour, with fluffy white feathers towards its back end, and lacking the Brown Thornbill's crescent markings on the forehead.
The Yellow Wattlebird is larger than our Red Wattlebird and has an even more raucous call; similarly the Yellow-throated Honeyeater is larger than the New Holland. These are quite common birds that eat a lot of insects. As well, there is the Strong-billed Honeyeater, which behaves like a treecreeper, a group that is not represented in Tasmania. Strong-billed Honeyeaters are mainly insectivorous, social and quite nomadic. The other endemic honeyeater is the Black-headed Honeyeater.
The endemic Black Currawong has only a little white on wing and tail, a sharp golden eye and a HUGE beak. Like our currawongs, during winter it comes down from mountains. The Grey Currawong in Tasmania is black rather than grey, but is clearly identified because of its more slender bill and distinctive clinking call. The only corvid in Tasmania is the Forest Raven.
Swift Parrots arrive in September and leave in March, breeding when the large blue-gum flowers are available. Bruny is a stronghold for these birds, which nest communally in stringybarks and feed in blue-gums. There are 14 Swift Parrot nests on Tonia's property.
Tonia finished her talk by discussing many of the interesting seabirds, including albatrosses. King Penguins and Rock-hoppers occasionally come ashore. Fairy Penguins are common and can be seen from the boardwalks on Bruny Island.
Thanks to Tonia for a well-illustrated, entertaining and informative talk.
Ian Anderson
Those of us who have been in COG for many years were delighted to have Dr Sonia Tidemann among us again. We don't see her often as she is now a senior lecturer at Batchelor College 300 km south of Darwin. Her research has carried her from delightful fairy-wrens to the stunning Gouldian Finches of our far north. Although her presentation was unexpected, last and only a short 10 minutes, it was a feast for the eyes and ears.
The colourful but endangered Gouldian Finch Erythrura gouldiae is distributed along the top northern edge of Australia. In Queensland, populations are small and not secure; however in certain areas of the NT and in the Kimberley they are secure.
Where they are doing well they breed prolifically, raising several broods a year. The male forays out to have a look at suitable nesting sites in hollow spouts of the Salmon Gum (which is also favoured by didgeridoo players so there is a bit of competition here!). Then the female comes and does a lengthy and thorough inspection while the proud male patiently waits outside. Both sexes feed the young, who are voracious eaters; if one parent disappears, the remaining one is not able to keep the clutch alive (except for one brave and exhausted male which Sonia observed).
Gouldian Finches feed exclusively on seeds (not even a tasty termite), especially on the plentiful, tall and wicked-to-walk-though speargrasses such as Sorghum plumosum and S. intrans, which grow in profusion under the Salmon Gums.
Populations of finches have been decimated by infection from the air-sac mite Sternostoma tracheacolum. This fatal disease was first found in 1946 on canaries and eventually infected 66% of our wild finches. Infected birds sound as though they are wheezing with asthma. A bird can be cured with an appropriate one-off dose of 'ivomec' used by veterinarians for larger animals. The mind boggles at a project like that - any volunteers?
Kay Hahne
Denis Saunders from CSIRO Wildlife and Ecology described a project in southwestern Western Australia to investigate the importance of roadside vegetation corridors for birds. Once this area was well vegetated, but clearing for extensive agriculture, particularly wheat, has left only scattered remnants of native vegetation.
Banding was carried out from 1984 to1995 four times a year, for two weeks each time. This intensive work required many volunteers, and Denis recruited them through Earthwatch, an organisation that brings together researchers and people who pay to spend their holidays participating in field research.
There were 31 banding sites, 18 on patches of remnant vegetation, 13 on linear strips along roads. The remnant patches were scattered throughout the area, while most of the relatively well-vegetated road verges ran north-south (except for farm roads with little vegetation). Therefore birds dependent on native vegetation could use roadside corridors to move between remnants in a north-south direction, but would have to fly over open ground to move between remnants in an east-west direction.
Sixty-nine species were trapped and nearly 12,000 banded. There was a high retrap rate (15.5%). The most commonly caught species was the Singing Honeyeater. This was a big change from early this century, when the Yellow-plumed Honeyeater was the most common species; like other woodland species (eg Rufous Treecreeper and Purple-crowned Lorikeet), the Yellow-plumed Honeyeater has become scarce or extinct in the area as woodlands were indicative of better soils for agriculture and most of the woodlands have been cleared. Singing Honeyeaters are known to cross open ground; however in this study their movement patterns indicated that they moved along linkages of remnant vegetation.
The banding data suggest that the corridors could be particularly important for the White-eared Honeyeater, which does not fly over open ground, and the Brown-headed Honeyeater, which travels in small groups. The corridors may be less important for Brown Honeyeaters, which move along the corridors but also move east-west over open ground.
The random locations of the remnants and verges make it impossible to carry out controlled replicable studies to categorically 'prove' the importance of the corridors for bird movements. However, the overwhelming evidence from the study is that many species do require the corridors. Losing the linkages is therefore likely to result in the extinction of some species, and in at least some instances this may have a noticeable functional impact. For example, nectar feeders may be important in pollinating native shrubs, and loss of native shrubs may lead to increased soil salinity. Studies of this kind are therefore important in providing data to guide decisions about land management, landscape design and landscape reconstruction.
Chris Tidemann, School of Resource Management and Environmental Science at the Australian National University, kindly summarised his own talk for those of us not able to hear him speak.
Common Mynas, Acridotheres tristis, originated in India, where they are known as 'farmers' friends' because of their appetite for insects. Mynas were brought to Melbourne in the 1860s to control insect pests in market gardens, and descendants of these birds were shipped to north Queensland and New Zealand for the same reason. Mynas have now established along much of the eastern seaboard of Australia, in many cases their spread assisted by people. The ACT managed to escape mynas for a time, but some were brought from Sydney in the 1960s. Mynas are popular as talking cage birds in many parts of the world.
Thirty years later, mynas have colonised nearly all Canberra suburbs and the densities are still rising, even in the central southern suburbs, where they first established. The rate of spread has been quite slow, which suggests that localised control is more likely to be effective than with, for example, the highly mobile Common Starling. Control of populations is desirable because mynas impact negatively on many hollow-dependent birds and mammals, and probably also some species that do not depend on hollows.
Canberra Nature Parks provide an ideal opportunity to measure the impact on biodiversity of two methods of localised control of mynas: (1) trapping chicks in customised nest-boxes and (2) trapping adults in artifical roosts. I hope to initiate these trials later this year, in collaboration with COG and the ACT Parks and Conservation Service.
For 35 years Steve Wilson has been sharing his knowledge of birds with COG audiences. This time he gave us some useful pointers to help identify cuckoo-shrikes. The main trap is in identifying the juvenile Black-faced and adult White-bellied Cuckoo-shrikes. The significant point is that in the Black-faced the black extends well behind the eye in the juvenile and adult, whereas it terminates at the eye in the White-bellied. An odd one is the dark morph of the White-bellied, which has a totally black crown, and dark upperparts, breast and chest. Some ACT records of the White-bellied Cuckoo-shrike are of the dark morph.
Shirley Kral reports on 'a buffet of delectable nibbles'!
David Pfanner presented verbal and musical pictures of recent thrilling bird sightings, using his own compositions for the sopranino and bass recorders: a Chestnut Rail in a cloud of mossies in Darwin; hundreds of Banded Stilts on Rottnest Island; a Black Grasswren in the Kimberley.
Anthony Overs brought us up to date on the woodland survey, with the highs and lows of the various sites and a plea for more helpers.
Graham Stephinson again 'gasted our flabbers' with his stupendous bird slides of 1998. Highlights were the Black-tailed Yellow Cockatoo (no, this is not a misprint!), a Plumed Whistling-Duck consorting with Black Swans on Lake Burley Griffin, a Scarlet Robin feeding young and a prize-winning slide of a male Gang-gang feeding on red berries.
Geoffrey Dabb titillated us with mystery bird slides, supplied by Mark Clayton. His quest for Fairy Martins had taken him on rough roads from Hillston north to Charleville, the martins having a fine colour sense in their multicoloured red mud nests and producing a ghostly effect when erupting from the nest entrance.
Alistair Bestow changed the pace with vignettes from Thomas Hardy and Dylan Thomas's 'Under Milkwood'; an ageless Monty Python sketch about purchasing a bird book in a bookshop; and, finally, a serene section from 'The Lark Ascending', by Vaughan Williams, that quintessential piece of English music which more than anything takes me back to an English childhood.
Alan Scrymgeour closed the evening garlanded with a gently wriggling Water Python and Brettle's Python. With accompanying slides of reptiles' gargantuan maws swallowing birds and bushrats, he described how some birds get their own back by taking snakes and lizards. Before being almost throttled, he issued a timely warning on how to conduct oneself when confronted by snakes.