 |
| Western Ground Parrots - Pic by Perth Zoo |
THIS ARTICLE WAS PUBLISHED IN THE WEEKEND AUSTRALIAN OF 6-7 January, 2018
As the sun sets over
Cape Arid National Park on the rugged south coast of Western
Australia, the silence is broken by a flute-like cadence. A bird on
the brink of extinction welcomes the night with a song of rare purity
floating above an expanse of knee-high heath ablaze with wildflowers.
Not at all parrot-like, this is the call of the western ground
parrot, with a total world population occurring nowhere but within
the boundaries of this remote national park.
The western ground
parrot was once much more numerous. Its range extended historically
hundreds of kilometres west and north of Cape Arid to beyond Perth.
The species crumbled in the wake of habitat destruction, raging wild
fires and predation from introduced foxes and cats; in recent years
it has vanished from most of its remaining haunts.
Alarmed by the
parrot's precipitous decline, government authorities responded with
what has become a standard strategy in Australia to try to bring
endangered wildlife back from the brink. A captive-breeding program
was established. Wild western ground parrots were caught and
transferred to Perth Zoo in the hope they would breed in captivity.
Their offspring would be introduced to the wild with the aim of
boosting populations; that at least was the plan.
Even more scarce
than the western ground parrot is the orange-bellied parrot. The
orange-bellied parrot breeds in the wild in one small area around
Melaleuca in south-west Tasmania. This summer nesting season, just 19
parrots returned to Melaleuca from the annual winter migration
undertaken by the species from Tasmania to the coastal salt marshes
of Victoria. The species was described as “locally abundant” a
century ago.
Like the western
ground parrot, desperate measures are under way to boost the remnant
population of orange-bellied parrots with releases from a
captive-breeding program. Yet for different reasons, both programs
appear doomed to fail. Critical questions are now being asked about
the suitability of breeding programs as a key environmental
management tool in Australia. Most disturbingly, it is arguable that
poorly executed if well-meaning programs may perversely contribute to
extinctions.
Estimates of the
wild western ground parrot population are accurate because its
distinctive calls are monitored by acoustic recording units deployed
at Cape Arid. Twelve parrots - almost 10 per cent of the survivors -
have been caught and transferred to Perth Zoo since the captive
breeding program was initiated in 2014.
 |
| Western Ground Parrot. Pic by Perth Zoo |
Eight of the 12
captured parrots are dead. One died from injuries sustained during
capture; another because it was egg bound. Six parrots died of
aspergillosis – a respiratory infection caused by a type of mould.
The two parrots caught most recently - both young birds - died of
aspergillosis while in quarantine before they could be transferred to
breeding aviaries. The zoo has four surviving western ground parrots
– three males and a female.
Moreover, not a
single nestling has emerged from repeated breeding attempts over four
seasons. Ten of 11 eggs laid by the surviving female, Fifi, were
infertile; the embryo in one egg died. However, the WA Department of
Biodiversity, Conservation and Attractions plans to capture more wild
parrots for the program in 2018. The number to be caught will be
determined following “monitoring of the wild population”, says a
departmental spokersperson.
Perth Zoo fauna
supervisor Arthur Ferguson insists the captured parrots have not died
in vain. “Much has been learned about factors that contribute to
aspergillosis in parrots and husbandry and management practices have
been refined considerably to minimise such risks,” Ferguson says.
“Perth Zoo are experts at native species breeding, having helped
reverse the fate of species on the brink including Australia’s
rarest reptile, the western swamp tortoise, and the western quoll.”
The project's poor
track record is sobering nonetheless. “We are very disappointed
that there has been no success,” says Anne Bondin, chairwoman of
Friends of the Western Ground Parrot, a community group trying to
raise $85,000 for the project.
Says Perth
ornithologist Frank O'Connor: “Without a successful captive
breeding program I believe the species is doomed, possibly within a
decade.”
On the other side of
the Great Australian Bight, the orange-bellied parrot is on an even
faster track to extinction in the wild. A long-running
captive-breeding program in Tasmania has failed to boost the
dwindling stock of wild orange-bellied parrots, notwithstanding an
important difference from the western ground parrot experience.
 |
| Orange-bellied Parrot . Pic by Save The Orange-bellied Parrot |
Unlike the western
birds, orange-bellied parrots breed well in captivity; about 350
birds are thriving in aviaries. The problem is that the captive-bred
parrots are not good at surviving in the wild. They continue to be
released at the Melaleuca breeding station – 23 parrots raised in
aviaries were freed this season – but the program is faltering.
Out of 62
captive-bred parrots released between 2013 and 2015, according to
data seen by Inquirer, just seven were spotted 12 months after
their release, having survived the hazardous winter migration to the
mainland. In 2016, 23 birds were released but 10 were recaptured and
returned to aviaries for the winter; just one of the other 13
returned this season.
Zoologist Mark
Holdsworth, who has been closely involved with the program for many
years, says on average about half the wild parrots would naturally
survive the migration, but the proportion is much lower for
captive-bred birds. Holdsworth believes all parrots born at Melaleuca
this season – whether or not their parents were captive bred -
should be captured. Twenty fledglings were produced last year at
Melaleuca but only four returned to the breeding station
post-migration. “If nothing is done this season to improve survival
then the species is likely to be extinct in the wild by next season,”
Holdsworth says.
During the 2015
season, 19 nestlings and one adult at Melaleuca tested positive for
the often fatal psittacine feather and beak disease, believed to have
originated in aviaries. Of the 19 birds to return this season just
three are females, one of which was captured because it was thought
to have a disease. Australia's leading authority on native parrots,
Joseph Forshaw, says a “total rethink on our approach to saving
this species” is needed.
But the Tasmanian
Government continues to back the program. Department of Primary
Industries, Parks, Water and Environment policy manager Andrew Crane
says the parents of one wild-born parrot which returned this season
were captive bred. “This is a good example of the significance of
the breeding program and one which is not immediately obvious from
the raw data,” Crane adds.
 |
| Eastern Bristlebird - northern race |
A rare Australian
songbird, the eastern bristlebird, is faring a little better than the
parrots; the population of bristlebirds in southern NSW and Victoria,
although in decline, numbers several hundred. However, the
distinctive northern population of the species is critically
endangered, with less than 30 birds surviving in the mountains of the
Queensland-New South Wales border area.
A captive-breeding
program for the northern bristlebirds began at the David Fleay
Wildlife Park on the Gold Coast in 2004 but was discontinued in 2009.
Eight birds raised in aviaries were released in the wild. Four that
were set free at Spicer's Gap in Queensland in 2008 were dead within
12 months of their release; the fate of another four released in NSW
is uncertain.
A second breeding
program for the birds was established in 2015 at the Currumbin
Wildlife Sanctuary, also on the Gold Coast. The sanctuary says on its
website that plans to collect the eggs and chicks of wild birds are
under way so captive-bred birds could “provide a sustainable boost
to this endangered population”. An English springer spaniel has
been trained to track down the handful of nests of surviving wild
birds so their eggs and chicks can be removed.
Herein lies the
dilemma that is central to the captive-breeding program strategy.
When numbers of an endangered species are critically low, might that
species be pushed over the brink if the survivors are caught for a
breeding program which may not succeed? Or can authorities reasonably
assume that a species is doomed to extinction in the wild anyway, and
reason that its only chance for survival is captive-breeding?
 |
| Lord Howe Woodhen. Pic by NSW Office of Environment & Heritage |
Breeding programs
have had some outstanding successes. The flightless Lord Howe woodhen
is found only on Lord Howe Island. After the island's settlement in
the 1830s, its population crashed in the face of an onslaught from
introduced rats, cats and pigs. By 1980, when a captive-breeding
program began, just 15 birds survived on the summits of two
mountains.
Three woodhen pairs
captured for the program produced 66 chicks. Today, with introduced
pests eliminated, the woodhen has recolonised the island. Birds are
commonly encountered in the gardens of the island's settlement. The
estimated population of 240 is probably close to what it was
naturally.
Australia has the
world's highest rate of mammal extinctions; birds have only recently
begun to catch up. The Lord Howe woodhen was brought back from the
brink, as have several endangered species in New Zealand, a world
leader in pioneering captive-breeding. Such successes have led to a
widespread view by authorities in Australia that breeding programs
are a panacea: a solution to arrest the country's appalling wildlife
extinction record. That view may in some instances be gravely
misplaced.
