A parasite attack on Darwin’s finches means they’re losing their lovesong



A Small Tree Finch from the Galápagos Islands with an enlarged nostril caused by a parasite.
Katharina J Peters, Author provided

Katharina J. Peters, Flinders University and Sonia Kleindorfer, Flinders University

A parasite known to infect beaks in some iconic Darwin finches on the Galapagos Islands is changing the mating song of male birds.

Our research, published today in Proceedings of the Royal Society B, reveals how the parasite deforms the beak. This has the effect of weakening the male bird’s mating call, and making it no longer clearly distinguishable from that of other closely related species.

A changed song can have an important effect on the male finch’s ability to find a mate.




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It’s another factor that could contribute to declining numbers of these already threatened birds on the Pacific archipelago, about 1,000km off the coast of South America.

A family song to impress

A male finch learns the mating song from his father, and produces the same song for the rest of his life.

It’s a simple tune consisting of one syllable repeated 3 to 15 times, depending on what species of finch he belongs to. Larger-bodied finch species produce a slower song with few syllable repeats, and smaller-bodied finch species produce faster song with many syllable repeats.

Whatever species of finch you belong to, hitting the high notes is important – because females prefer males who can produce such vocally challenging songs.

In the case of the Medium Tree Finch (Camarhynchus pauper), a critically endangered species that only occurs on Floreana Island of the Galapagos Islands, its species-typical song has a bright resonance that rings across the forest canopy.

Medium Tree Finch.
Author provided35.5 KB (download)

An accomplished male singer that can hit the high notes is quickly swooped up by a female looking to pair with a proficient singer.

The ‘Vampire’ parasite

The Vampire Fly – a suggested name for the parasite Philornis downsi given its blood feeding habits from dusk until dawn – was first discovered in a Darwin’s finch nest in 1997.

The parasitic Philornis larvae in a finch nest.
Sonia Kleindorfer, Author provided

Since then, the devastating impacts of its larval feeding habits on nestling birds have been coming to light. The adult fly is vegetarian, but the females lay their eggs into bird nests and their larvae feed on nestling bird beaks from the inside out.

Many Darwin’s finch species now have beaks with massively enlarged nostrils because of damage the feeding fly larvae have caused during the nestling stage. We discovered that a changed beak apparatus measurably affects the song of Darwin’s tree finches with consequences for pairing success.

A Medium Tree Finch male with extremely enlarged nostrils is unable to hit the high notes.

Medium Tree Finch with enlarged nostrils.
Author provided32.2 KB (download)

We found the same pattern in Small Tree Finches (C. parvulus) with enlarged nostrils.

Male finches that produce song with a narrower frequency bandwidth, because their song has a lower maximum frequency, have poor quality song. These males are less likely to be chosen by females, a pattern we documented in both the Medium Tree Finch and the Small Tree Finch.

Also, the song of Medium Tree Finches with enlarged nostrils sounds like the song of the Small Tree Finch.

Small Tree Finches.
Author provided29 KB (download)

When species merge

But confusion among the species and their mating songs may not necessarily be a bad thing for the future survival of individual finches – though it could herald the collapse of species lineages.

Previously, we discovered evidence of hybridisation in Darwin finches. This is where two separate species of finch breed which could potentially produce a new species, phase out one of the species, or cause the collapse of the two existing species into one.

We observed hybridisation driven by female Medium Tree Finches pairing with male Small Tree Finches.

When a female Medium Tree Finch inspects male Small Tree Finches in the forest, she pairs with one who produces high quality song, even if that male is from another species.

A Tree Finch with a normal beak and nostril size, so no infection from the parasite.
Katharina J Peters, Author provided

This female choice seems to be paying dividends, because hybrid pairs with greater genetic diversity also sustained fewer of the parasitic larvae in the nest. And that could lead to fewer birds with infected beaks.




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There are concerted efforts underway to develop control and eradication methods for P. downsi on the Galapagos Islands, building on a collaborative relationship between the Charles Darwin Foundation and the Galapagos National Parks. The Philornis downsi Action Group is an international consortium of concerned scientists working to develop biological control methods.

Our new research is an important step towards understanding how this invasive fly may be changing the evolutionary pathway of Darwin’s finches by literally changing the beak of the finch.The Conversation

Katharina J. Peters, Postdoctoral fellow, Flinders University and Sonia Kleindorfer, Professor of Animal Behaviour, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Adani’s finch plan is approved, just weeks after being sent back to the drawing board


Stephen Garnett, Charles Darwin University; Brendan Wintle, University of Melbourne; David Lindenmayer, Australian National University; Don Franklin, Charles Darwin University, and John Woinarski, Charles Darwin University

The Queensland government has ticked off a crucial environmental approval for Adani’s Carmichael coalmine, bringing the contentious project a step closer to becoming reality.

It has approved Adani’s proposed management plan for the endangered black-throated finch, less than a month after the state’s environment department announced a delay in approval because the plan was judged to be inadequate.




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Why Adani’s finch plan was rejected, and what comes next


Four days after the May 18 federal election, in which the mine’s future was a prominent issue, Queensland Premier Annastacia Palaszczuk called for an end to the delays and uncertainty.

In a statement issued today, the government said it has now approved a “strengthened” version of the plan, submitted by Adani earlier this week.

Under the revised plan, Adani has now committed to:

  • “establish enhanced understanding” of the finch, with the help of “appropriate population studies”

  • implement “appropriate monitoring protocols” to track the finch’s population over time

  • restrict grazing in nearby areas.

The only remaining state environmental approval for the project now is Adani’s groundwater management plan, on which a decision is due by June 13.

Bad plan caused the delays

As members of the scientific panel that reviewed the finch management plan, we can understand the Premier’s frustration. There is no excuse for such a poor plan to have been put forward for approval when the company has been aware for almost a decade that the land it wants to mine is home to the largest known remaining population of the black-throated finch.

There has already been ample time to undertake the studies Adani has pledged to carry out in the future. Had it done so before now, it could have put its claims to be able to manage the finch’s extinction risk on a much more solid footing.

As it is, the plan we reviewed made biologically improbable assumptions about the finch, while ignoring what is known about the finch’s precipitous decline so far. Under the plan, people with the curious title of “fauna spotter-catchers” were to find finches and move them “to suitable habitat adjacent to the disturbance, if practical” before the habitat is destroyed.

It sounds impractical, and will in all likelihood prove to be so. If the adjacent habitat already has finches, it is likely to be “full” and so won’t be able to support mining refugees. If it lacks finches, there is probably a very good reason.

The finch has been observed only a handful of times in just a tiny proportion of the area purchased for conservation purposes near the mine site. The finch has had more than 10,000 years to occupy and breed in the proposed conservation area that is supposed to offset the impact of the mine. It hasn’t, and it probably won’t.

As far as can be determined by overlaying the available maps, the proposed conservation area has a different geology and soil type. Adani has categorically failed to provide robust scientific evidence to demonstrate that the conservation reserve will adequately offset the loss of the finches and the habitat in the mined area. It has had more than 10 years to conduct the science to provide the evidence.



Meanwhile, before the existing habitat is mined, the plan had talked about grazing being used to control bushfire fuel loads and reduce the abundance of a weed called buffel grass. Yet grazing is thought to be the main reason the finches have disappeared from most of their once vast range – they once occurred from the Atherton tablelands to northern New South Wales.

The new plan is said to “restrict grazing” but no details are yet available. Under the original plan, the cattle would have got fat on the buffel grass pastures just as they did in all the places where the finch once lived.

Rigorous research

What must really frustrate the Queensland Premier is the contrast between Adani’s efforts with the black-throated finch and the much more rigorous work done by mining companies who find themselves in similar situations. Rio Tinto, for example, is currently funding high-quality research on two other birds, the palm cockatoo and red goshawk, ahead of its planned expansion of bauxite operations on Cape York Peninsula.

Vista Gold, meanwhile, funded research on stress levels in Gouldian finches long before mining was planned to begin at its Mt Todd goldmine in the Northern Territory.

In criticising Adani’s plan, we are not criticising mining. Like all Australians, we use the products of mining every day. We enjoy a high standard of living that is delivered partly by royalties from mining. We also understand that miners (and politicians) in Queensland want to see jobs created.

Most mining companies, however, provide jobs while willingly abiding by national and state legislation. They compromise where necessary to minimise environmental harm. And crucially, they commission research to demonstrate how they can mitigate damage well before that damage occurs, rather than when their operations are already underway.




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In contrast, the so-called research and monitoring that went into Adani’s finch plan seems only to conclude that more research is needed. After nine years, Adani did not even know the population size of the finch, how it moves around the landscape, or even what it eats.

Given the time available, this bird could (and should) have been among the best-studied in Australia. The management plan could then have been based on robust evidence that would show how best to safeguard the finch population.

Now the research and monitoring is a hurried add-on with no proof that the threat posed to the finch can actually be solved and an extinction averted. Given the high stakes involved, Australians might reasonably have expected something altogether more rigorous.The Conversation

Stephen Garnett, Professor of Conservation and Sustainable Livelihoods, Charles Darwin University; Brendan Wintle, Professor Conservation Ecology, University of Melbourne; David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University; Don Franklin, Adjunct Research Fellow, Research Institute for Environment and Livelihoods, Charles Darwin University, and John Woinarski, Professor (conservation biology), Charles Darwin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why Adani’s finch plan was rejected, and what comes next



The black-throated finch is on the verge of extinction.
Brian McCauley/flickr, CC BY-NC

Samantha Hepburn, Deakin University and April Reside, The University of Queensland

Adani’s plan to manage an endangered finch was rejected last week by the Queensland government, stalling progress on the Carmichael mine.

The mine would cover much of the best remaining habitat for the endangered black-throated finch. The Queensland government required Adani to commit to gathering more accurate finch population data, limit the cattle grazing in the finch conservation area and determine food availability throughout the year, before they could approve the plan.

The rejection is one of two outstanding environmental approvals required before Adani can commence work on the mine. The second is the plan to manage groundwater-dependent ecosystems, which the Queensland government has yet to come to a decision on.




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The federal government has been reported as “already approving” the finch plan. But legally, the Queensland government must determine whether the plan complies with the conditions of the environmental authority and, under the bilateral framework, the federal government must give due regard to this assessment.

What’s wrong with Adani’s plan?

Last Friday Queensland’s Department of Environment and Science decided not to approve Adani’s black-throated finch management plan because it does not fulfil certain basic requirements.

The decision is based on a detailed report from an independent expert panel.

The black-throated finch is on the verge of extinction, one of 238 threatened Australian birds.

The black-throated finch is experiencing habitat loss and degradation.
Steve Dew/flickr, CC BY



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The greatest threat to the black-throated finch is habitat loss: it has disappeared from over 80% of its original range. Strong protection, and careful management, of its remaining habitat is crucial.

The finch, once found across north-eastern Australia, is now largely found on Moray Downs and surrounding properties, north-west of Clermont in central Queensland. A core part of the habitat is within the 28,000 hectare (ha) footprint of the Carmichael mine, where there are far more black finches than elsewhere due to the intact woodlands and a history of minimal livestock grazing.

It is expected the mines will disturb 50,977 ha of black-throated finch habitat, and that 34,156 ha will be completely cleared.

A total of 87 square kilometres of habitat will be destroyed through the creation of open pits, and a further 61 square kilometres may be degraded beyond repair due to the influence of underground mining on groundwater.

After habitat loss, the second greatest threat to the finch is cattle grazing, which destroys the grass seeds they need to survive. Yet Adani’s management plan for the black-throated finch involved grazing cattle on areas that are supposed to be devoted to conservation of the finch.

Instead of establishing a finch conservation reserve, the Adani plan proposed what was in effect a paddock. Providing a species management plan that effectively conserves finch habitat is a core condition of Adani’s mining licence.

State vs federal priorities

The Queensland government’s rejection of the plan brings into stark focus some of the problems with the existing environmental assessment framework.

The Adani plan includes cattle grazing, despite the threat to finch habitats.
Shutterstock

The environmental authority for the mining licence was approved by the Federal government. The environmental management plan for the finch did not, however, address core impact concerns. And yet this is the very reason that the plan was required from the outset. The inadequacies of the plan only became apparent because of the oversight of the Queensland government.

The federal government has not been proactive despite’s its mandate under our National environment act – the Environmental Protection Biodiversity Conservation act. In fact, a recent analysis found the federal government has approved hundreds of projects to clear black-throated finch habitat over the last 18 years.




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There are clearly differences in priorities regarding the environment between a federal Liberal and a state Labor government. However, environmental assessment can only be effective if is not undermined by political agendas, and is grounded in scientific rigour and scrutiny.

A one-stop shop

At the federal level, any project likely to have a “significant impact” on a matter protected by the Environment Protection and Biodiversity Conservation Act must be referred to the federal environment minister.

If the minister decides the project impacts a matter of national environmental significance, he or she will then determine how to assess that project at the national level. Legislated options include: an environmental impact statement, a public environment report and public inquiry.

The federal government has entered into bilateral agreements with all state and territory governments. As a result, rather than the state and federal governments conducting separate assessment, the aim is to promote a single, focused environmental evaluation.

The Queensland government has entered into a bilateral assessment agreement with the Commonwealth government for Adani’s coal project, which effectively allows it to make an environmental assessment that the Commonwealth Minister will then take account of when deciding whether to grant approval.

This means that both the Queensland and the federal government are involved in the approval and assessment process environmental authorities and conditions, one of those being the management plan for the black-throated finch. In order to optimise outcomes they need to work together collaboratively.

Where to next?

The rejection means that Adani will now need to submit a new or revised plan that addresses the Queensland government’s concerns. In particular, Adani will need to limit cattle grazing in the conservation area, and gather more information regarding the availability of seed throughout the year.

This may take time but is critical, because in its current form, the plan does not meet the legal requirements for the Environmental Authority, which means that it cannot be approved at the state level.

Without state approval the Adani coal mine cannot proceed. The Queensland government has rigorously assessed Adani’s management plan by commissioning a report by an independent expert panel and then acting on the advice of this report.

This robust approach is crucial to the whole framework of environmental assessment. Genuine commitment to protecting endangered species and managing vital groundwater resources is vital if we want to reverse Australia’s dire trajectory of environmental decline.The Conversation

Samantha Hepburn, Director of the Centre for Energy and Natural Resources Law, Deakin Law School, Deakin University and April Reside, Researcher, Centre for Biodiversity and Conservation Science, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Death by 775 cuts: how conservation law is failing the black-throated finch


April Reside, The University of Queensland and James Watson, The University of Queensland

Nearly 20 years ago, Australia adopted national environmental legislation that was celebrated widely as a balanced response to Australia’s threatened species crisis. In the same year, Queensland introduced its Vegetation Management Act. Together, these laws were meant to help prevent further extinctions.

But have they worked?

A famous finch

We investigated whether these laws had successfully protected the habitat of the endangered southern black-throated finch.

Our study found that, despite being nominally protected under federal environmental law, habitat for the species has continued to be cleared. Just three out of 775 development applications that potentially impacted the endangered southern black-throated finch were knocked back, according to our new research.




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Defining exactly what is habitat for the black-throated finch is tricky – we don’t have oodles of data on their habitat use over time, and the extent of their sightings has declined substantially. But Queensland has excellent vegetation mapping, and we recorded all of the vegetation types in which the southern black-throated finch has been seen.

We then mapped the extent of this habitat in three different time periods: historically; at the advent of the environmental laws (2000); and current day.

Clear danger

We found that most of the black-throated finch’s habitat had been cleared before 2000, mainly for agriculture before the mid-1970s. The black-throated finch hasn’t been reliably seen in New South Wales since 1994 and is listed there as “presumed extinct”.

We looked at all the development proposals since 2000 that were referred to the federal government due to their potential impact on threatened species. 775 of these development proposals overlapped areas of potential habitat for the black-throated finch.

Only one of these projects – a housing development near Townsville – was refused approval because it was deemed to have a “clearly unacceptable” impact to the black-throated finch.

In addition to these projects, over half a million hectares of the cleared habitat were not even assessed under federal environmental laws.

We estimate that the species remains in just 12% of its original range. Yet despite this, our study shows that the habitat clearing is still being approved within the little that is left.

So in theory, Australia’s and Queensland’s laws protect endangered species habitat. But in practice, a lot has been lost.

Critical habitat

The highest-profile development proposal to impinge on black-throated finch habitat loss is Adani’s Carmichael coalmine and rail project. Adani has been given approval to clear or otherwise impact more than 16,000 hectares of black-throated finch habitat, a third of which Adani deemed “critical habitat” But there are four other mines in the Galilee Basin that have approved the clearing of more than 29,000 ha in total of black-throated finch habitat.

But it’s not just the mines. In 2018 the federal government approved clearing of black-throated finch habitat for a housing estate and a sugar cane farm, both near Townsville. Several solar farms have also been proposed that would clear black-throated finch habitat around Townsville.

To further complicate matters, the black-throated finch’s habitat is also threatened with degradation by cattle grazing. The finch needs year-round access to certain grass seeds, so where grazing has removed the seeding part of the grasses, made the ground too hard, or caused the proliferation of introduced grasses such as buffel, the habitat suitability can decrease until it is no longer able to support black-throated finches.

So while they are losing their high-quality habitat to development, a lot of their habitat is being degraded elsewhere.

Heavy cattle grazing degrades habitat for the southern black-throated finch by removing edible grass seeds.
April Reside

The federal government has placed conditions on approved clearing of black-throated finch habitat, often including “offsetting” of any habitat loss. But securing one part of the black-throated finch’s habitat in exchange for losing another still means there is less habitat. This is particularly problematic when the lost habitat is of very high quality, as is the case for Adani’s Carmichael coalmine lease.

Little by little

Our research suggests there is a real danger of the black-throated finch suffering extinction by a thousand cuts – or perhaps 775 cuts, in this case. Each new development approval may have a relatively modest impact in isolation, but the cumulative effect can be devastating. This may explain why a stronger environmental response has not occurred so far.




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So how can we prevent the black-throated finch from going extinct? The finch is endangered because its habitat continues to be lost. So its recovery relies upon halting the ongoing loss of habitat – and ultimately, increasing it. Achieving this would require a political willingness to prioritise endangered species protection.

Australia has already lost hundreds of its unique plants and animals forever. In just the last few years, we have seen more mammals and reptiles disappear to extinction. If we continue on our current path, the southern black-throated finch could be among the next to go.The Conversation

April Reside, Researcher, Centre for Biodiversity and Conservation Science, The University of Queensland and James Watson, Professor, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Queensland coal mines will push threatened finch closer to extinction


Eric Vanderduys, CSIRO and April Reside, James Cook University

Australia has a bad record for losing species, and more are likely to follow: more than 1,700 species of animals and plants are listed by the Australian government as being seriously threatened.

The extinction of a species usually comes about from several interacting threats, and the extinction process usually starts with losing a few populations, or a particular subspecies, until eventually there are only a few individuals remaining.

The southern black-throated finch, Poephila cincta cincta, is a bird that has become endangered mostly through land modified by agriculture, resulting in the loss of around 80% of its former range.

Our research, published in PLoS ONE, shows that more than half of the remaining finch habitat is potentially subject to mining development.

Pushed out of home

Map showing distribution of recent records of southern black-throated finches and records pre-2000.
Vanderduys et al PLoS ONE

The other subspecies, the northern black-throated finch Poephila cincta atropygialis, is believed to be secure, as it occupies habitat on the less-developed Cape York Peninsula.

The southern black-throated finch is almost entirely restricted to an area from Rockhampton north to Townsville, and has been declared extinct in New South Wales. The northernmost part of its range is threatened by urban and peri-urban development around the northern Queensland city of Townsville.

The largest remaining stronghold for black-throated finches is within the Galilee Basin, a 500 km-long coal measure running from around Alpha to Hughenden.

Within this area are the proposed Adani (Carmichael), Alpha, Kevin’s Corner, China First, China Stone and South Galilee coal mines. Collectively, these cover nearly 1,700 square km. Much of this area is proposed to be open cut. The Carmichael mine in particular covers the best “hotspot” known for black-throated finches. Were these mines to go ahead, the finches are likely to suffer steep declines.

In our paper we modelled likely black-throated finch distribution, based on what we know about their habitat and climate preferences. Given their historic decline throughout much of their range, we know they are quite sensitive to land modification, so it is unlikely that areas where mining and associated activities occur will be finch-friendly.

Around 60% of the finch’s remaining habitat is potentially threatened by mining activities. Our research also shows that of the very high-quality habitat known in the Galilee Basin, 50% is under threat from mines that have undergone advanced planning.

Map showing area modelled as prime southern black-throated finch habitat and overlaid with all exploratory and extractive (mining) tenures. The approximate boundary of the Galilee Basin is also shown.
Vanderduys et al PLOS One

Offset the damage?

So what does the government do when faced with a threatened species or subspecies in the face of large development proposals? The answer is to offset.

Offsets mainly involve conserving a species’ preferred habitat to account for what has been lost to development, but they could be also be in the form of research funding.

Offsets have been proposed to help reduce the impact on the black-throated finch, but these measures do not stand up to scrutiny.

First, offsets are supposed to result in “no net loss” of that species. In the case of black-throated finches, this means offsets should maintain the population at roughly the same trajectory as they would be on without the mining.

Second, areas proposed as offsets for one mine are potentially subject to development approval for other mines.

However, for a species that has lost 80% of its range (and is therefore demonstrably sensitive), losing any more of its key habitat guarantees an increased loss of finches.

The existing, mine-free finch populations in the Galilee Basin are currently doing well. To truly offset losing this habitat to mining, new high-quality habitat for black-throated finches would have to be created.

This has never been done. Not to mention the difficulty in achieving accurate population estimates in areas of “lost” or “gained” habitat.

Black-throated finches eat grass and herb seeds after they’ve fallen to the ground, so they need particular seeds to be available throughout the year, with just enough bare ground so they can find them. We are still in the process of trying to understand all the factors that make high-quality habitat for black-throated finches, and we’re a long way from having the expertise to recreate it.

Offsets are widely regarded in the scientific literature as failing. They are locking in species declines; far from guaranteeing survival of threatened species, they are guaranteeing their loss.

For the southern black-throated finch, which has already lost 80% of its range, losing 50% of what is known to be prime habitat within the Galilee Basin is likely to lock in its continuing decline.

The most reliable way of avoiding this decline would be to protect and enhance the little suitable habitat that still remains.

The Conversation

Eric Vanderduys, Research Projects Officer, CSIRO and April Reside, Postdoctoral Research Fellow in Spatial Ecology, James Cook University

This article was originally published on The Conversation. Read the original article.