Vanished and Vanishing Parrots

Profiling Extinct and Endangered Species

Joseph M. Forshaw, Frank Knight, Joseph Forshaw

• Publisher: CSIRO PUBLISHING
• Year: 2017
• Print ISBN: 9780643096325
• eBook ISBN: 9780643106505
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

Joseph M. Forshaw, one of the world's leading authorities on parrots, calls attention to the threats they face: they are one of the most endangered groups of birds, with a growing number of species nearing extinction. The main threats arise from habitat loss through deforestation and agricultural development and from the taking of birds for the international live-bird trade.

Vanished and Vanishing Parrots brings together information on species that have become extinct in historical times with information on species that are in danger of becoming extinct to increase public awareness of the plight of these magnificent birds. Vivid colour plates by the wildlife artist Frank Knight draw attention to the spectacular species that we have lost or that could be lost. Forshaw's work gives us fascinating insight into these endangered and extinct parrots.

Vanished and Vanishing Parrots will be a valuable reference for scientific, ornithological and avicultural organisations, as well as individual lovers of birds and of illustrated natural history books.

Announced Highly Commended at the 2018 Whitley Awards

AUSTRALASIAN DISTRIBUTION

The Australasian Distribution, as determined for this book, extends from the Philippine and Indonesian Archipelagos south to Australia and New Zealand, including offshore and subantarctic islands, and east to Henderson Island in eastern Polynesia. It is the only part of the worldwide distribution of parrots where all three superfamilies are represented, Strigopoidea and Cacatuoidea being endemic. Australia is the dominant landmass, and is where the highest number of parrot species occurs.

AUSTRALIA

In the 16th and 17th centuries, European traders coming to the ‘Spice Islands’ learned of a great land to the south where parrots were abundant, and early maps depicted Terra Psittacorum – the Land of Parrots, as an unknown landmass at the bottom of the world. The first European to record the abundance of parrots in the southern land was the English adventurer William Dampier, when on 22 August 1699 he visited one of the small islands in what is now the Dampier Archipelago, off the coast of northwestern Australia. In his Voyage to New Holland, published in 1703, Dampier described the birds seen on the island as ‘… some Cormorants, Gulls, Crab-catchers etc., a few small Land Birds, and a sort of White Parrot, which flew a great many together’. These ‘White Parrots’ were Little Corellas Cacatua sanguinea, which still occur on the islands.

‘Land of Parrots’ remains a term often applied to Australia, and seems appropriate because one-sixth of the world’s species occur there, with no other country having such a richness and diversity of forms. This strong diversity of forms, which so strongly differentiates Australia from other regions in the worldwide distribution of parrots, is a legacy of the Gondwanan ancestry of parrots, with focus on Australasia as the most likely centre of origin (Cracraft 2001). Molecular analyses support a Gondwanan origin of parrots, most probably during the Cretaceous, some 82 million years ago when New Zealand split from Gondwana and after the separation of Africa and the India-Madagascar block (Wright et al. 2008).

Since the time of European settlement, biologists and observers have been fascinated by Australian parrots. In his Handbook to the Birds of Australia, published in 1865, John Gould wrote:

No group of birds gives to Australia so tropical and foreign an air as the numerous species of this great family by which it is tenanted, each and all of which are individually very abundant.

The comment made by Gould about the abundance of parrots in Australia remains valid today, although there have been changes in the status of some species. Parrots are a very prominent component of the avifauna of the continent, and in every region they can be observed in good numbers.

Fortunately, the appalling extinction rate for Australian mammals is not mirrored in the loss of Australian birds, but since European settlement four parrots have been lost – the Norfolk Island Kaka Nestor productus, the Paradise Parrot Psephotellus pulcherrimus and two forms of the Red-fronted Parakeet Cyanoramphus novaezelandiae on Lord Howe and Macquarie Islands. Conversely, a few generalist species, notably the Galah Eolophus roseicapilla, the Sulphur-crested Cockatoo Cacatua galerita and the Little Corella C. sanguinea, have prospered since European settlement, but a number of more specialised species and populations with restricted ranges have declined, sometimes dramatically. Under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 the Orange-bellied Parrot Neophema chrysogaster and the Western Ground Parrot Pezoporus wallicus flaviventris are listed as critically endangered, and listed as endangered are Carnaby’s Black Cockatoo Calyptorhynchus latirostris, the Golden-shouldered Parrot Psephotellus chrysopterygius, the Swift Parrot Lathamus discolor, the Night Parrot Pezoporus occidentalis, the southeastern population of the Red-tailed Black Cockatoo Calyptorhynchus banksii graptogyne, the Kangaroo Island population of the Glossy Black Cockatoo C. lathami halmaturinus, the Norfolk Island population of the Red-fronted Parakeet Cyanoramphus novaezelandiae cookii and Coxen’s Fig Parrot Cyclopsitta coxeni. Baudin’s Black Cockatoo Calyptorhynchus baudinii meets criteria of the International Union for the Conservation of Nature (IUCN) for an endangered listing so is treated as such in this book (see Garnett et al. 2011).

A recent analysis of the ecological and socio-economic factors affecting extinction risk in parrots revealed that the most important threats to parrots are agriculture, hunting and trapping, logging, climate change and severe weather, invasive alien species, and residential and commercial development (Olah et al. 2016). All of these threats have affected or are affecting parrot populations in Australia, but particularly prominent are agriculture and logging. For more than two centuries, Australia has been a primary-producing nation supplying the traditional markets of Europe. Though often disclaimed, the phrase ‘Australia lives off the sheep’s back’ is a telltale statement with some validity. This prominence of primary production has resulted in widespread, sometimes dramatic changes to the natural environment, especially in humid coastal areas where agricultural and urban development has been concentrated. Recher (1985) points out that within 100 years of settlement in 1788, most of the Australian continent had been colonised and converted to farming or grazing lands. Landclearance has been excessive and wasteful, with widespread degradation, especially through salination, attesting to the futility of vegetation removal from marginal lands incapable of supporting profitable agricultural enterprises. Regrettably, this excessive landclearance continues, particularly in western Queensland. In recent times, mining has become increasingly prevalent in transformation of the Australian landscape, with large-scale open-cut extraction of minerals and coal resulting in significant local losses of natural vegetation. Logging has contributed to declines in populations of the Superb Parrot Polytelis swainsonii and the Regent Parrot P. anthopeplus, and Heinsohn identifies commercial logging, even on a small scale, on Cape York Peninsula as a potential threat to Eclectus Parrots Eclectus roratus (Garnett and Crowley 2000; in Curtis et al. 2012).

Since the time of European settlement there has been disturbance of all habitats. None has been destroyed completely, but some, including tropical or subtropical rainforest and mallee shrublands, have been gravely depleted. Consequently, parrot species have been affected in one way or another by human-induced changes. It appears that a few species, such as the Galah Eolophus roseicapilla, Little Corella Cacatua sanguinea and Port Lincoln Parrot Barnardius zonarius, have benefited, and others seem to have been little affected, but certainly there are signs that a number of species, especially those that are specialised in any way, now are declining. Summarising the abundance and population trends of Australian parrots, Smith (1978) concluded that 72 per cent of species appear to be holding their own, but only 60 per cent have stable or increasing populations. Noting a great increase in detailed ecological research on Australian parrots during the 1970s and 1980s, Joseph (1988) emphasises the need not only to continue that research and extend the number of species studied, but to conserve existing natural habitats in the face of often increasing pressures of agricultural and industrial development.

During field studies of the breeding biology of Carnaby’s Black Cockatoo Calyptorhynchus latirostris at two sites in Western Australia, it was found that, although each pair attempted to breed every year, the production of chicks per breeding unit at one site was only half that of the other site. Observations indicated that poor breeding success at the second site was due to a shortage of food, the parents being obliged to spend more time foraging in the scattered feeding areas. Some areas of useful food were not visited by the birds from one year to the next, so it seemed that the total amount of food in the area was sufficient, but because of its patchy distribution the birds did not have sufficient time to gather it. This important study demonstrates that breeding populations may be endangered by fragmentation of nearby feeding areas, despite a continuing sufficiency in total food resources.

At the same study sites in Western Australia, annual rates of loss of nesting hollows were 4.8 per cent and 2.2 per cent, and these exceeded the rates of formation of hollows. Losses were caused by trees being blown over, bulldozed or burnt in clearing operations, and by sections breaking away or collapsing into the hollows. At a study area within and adjacent to Iron Range National Park, on Cape York Peninsula, north Queensland, between 1999 and 2005, an average 5.2 per cent of nest-trees of Palm Cockatoos Probosciger aterrimus was lost each year, and these losses were due mainly to fire, followed by wind and then decay. The loss of mature, hollow-bearing trees is a problem throughout much of the continent, largely because of landclearance for agriculture and an increasing adoption of clear-felling practices in forests. Woodland on private property is generally over-mature, trees having been left to provide shelter for stock, and grazing prevents regeneration. Similarly, clear-felling in forests, particularly during wood-chipping operations, removes old trees, and harvesting is often repeated too frequently to allow replacement. I am concerned also about losses due to ‘dieback’, a term loosely applied to the effects of the root-attacking fungus Phytophthora cinnamomi and to severe outbreaks of defoliating insects. Such losses can be quite significant where woodlands already are fragmented because of large-scale landclearance or in specialised habitats such as woodlands of river red gums Eucalyptus camaldulensis on riverine floodplains.

There is ample evidence of wildlife populations being affected adversely by losses of hollow-bearing trees. In recent years, there have been increasing instances of multiple sequential, or even simultaneous occupation of hollows, and eviction of occupants by more aggressive species. In eastern and southern Australia, smaller parrots must contend with intense competition for nesting sites from introduced House Sparrows Passer domesticus, Common Starlings Sturnus vulgaris and Common Mynahs Acridotheres tristis. Rapid utilisation of hollow logs provided for Red-tailed Black Cockatoos Calyptorhynchus banksii at a breeding site in southwestern Victoria suggests that a shortage of suitable nesting hollows is an important factor contributing to the decline of that endangered population. Artificial nesting hollows are being utilised also by the critically endangered Orange-bellied Parrot Neophema chrysogaster in southwestern Tasmania and by Glossy Black Cockatoos Calyptorhynchus lathami on Kangaroo Island, South Australia.

Ground-feeding parrots are dependent on an abundance of seeding grasses and herbs, particularly during the breeding season, so changes in groundcover are potentially damaging to local populations. It has been suggested that in the early 1900s, severe drought, coupled with a rapid expansion of the cattle industry, brought about fundamental changes to groundcover vegetation in parts of central Queensland, and this probably contributed to extinction of the Paradise Parrot Psephotellus pulcherrimus and disappearance of the Turquoise Parrot Neophema pulchella from the northern sector of its range. I am of the opinion that similar changes, brought about by grazing and persistent dry-season burning, are responsible for the disappearance of Golden-shouldered Parrots Psephotellus chrysopterygius and Hooded Parrots P. dissimilis from parts of their ranges, and predation of adults and fledglings by Pied Butcherbirds Cracticus nigrogularis is a secondary pressure now assuming greater significance because of lower population levels.

The effects of secondary pressures, particularly disease, predation and hunting or trapping, are significantly increased when an affected species is already threatened by habitat loss. I see a pattern of disease and habitat loss combining to bring about near-extinction of the Orange-bellied Parrot Neophema chrysogaster in southeastern Australia. Again in southeastern Australia, recent studies have revealed that numbers of Swift Parrots Lathamus discolor are declining at an alarming rate, and the species is severely threatened by loss of habitat coupled with high predation at nests (Heinsohn et al. 2015). It was revealed also that in Tasmania survival of nests of these parrots is a function of mature forest cover in the surrounding landscape, with the likelihood of predation by introduced Sugar Gliders Petaurus breviceps increasing with decreasing forest cover brought about by logging operations. Trapping often is cited as a factor contributing to the decline of parrot populations. While not wishing to undermine the importance of ensuring adequate legal protection for parrots, I stress that nothing will be gained by prohibiting trapping if little is done to counteract the effects of habitat destruction – the two are complementary! I have no evidence of any Australian species currently being at risk from trapping, but chopping into nesting hollows to illegally remove eggs or chicks continues to threaten local populations of some Calyptorhynchus black cockatoos and Major Mitchell’s Cockatoo Lophochroa leadbeateri. I have no doubt that the taking of nestlings of Golden-shouldered Parrots Psephotellus chrysopterygius contributed significantly to the dramatic decline of that species during the 1960s and 1970s.

Of concern are the consequences of domestic trade in large numbers of live parrots or cockatoos. Since the 1970s, feral populations of some species, notably Little C...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Foreword
• Preface
• Introduction
• FOSSIL HISTORY OF PARROTS
• AUSTRALASIAN DISTRIBUTION
• AFRO-ASIAN DISTRIBUTION
• NEOTROPICAL DISTRIBUTION
• References cited
• Index of scientific names
• Index of English names