Why duck shooting season still isn’t on the endangered list

File 20180313 131572 1jzcc3i.jpg?ixlib=rb 1.1
The rising influence of the gun lobby in Australia may have extended the prospects of duck season continuing for the foreseeable future.

Siobhan O’Sullivan, UNSW

On March 17, the 2018 duck shooting session will open in Victoria. The first shots were fired in Tasmania and South Australia last weekend. The Northern Territory allows certain types of bird shooting later in the year. Duck shooting is prohibited in the rest of Australia.

States and territories have jurisdiction over duck shooting. In Victoria a new raft of regulations has been introduced to try to limit the damage to the state’s wetlands. One change of note in Victoria is that this year the Blue-winged Shoveler cannot be legally shot due to the low numbers of the species.

The Blue-winged Shoveler has been added to the protected list in Victoria this year for the first time.
Flickr CC

Other new regulations require that hunters recover the birds they shoot. This rule serves to formalise what Victoria’s Game Management Authority (GMA) refers to as “standard practice for responsible hunters”.

However, in most other respects Victoria’s 2018 duck season will look almost indistinguishable from previous years. It will still be three months long, with a “bag limit” of ten birds per person per day.

In Tasmania, authorities postponed the shooting start time in 2018, among a raft of other minor amendments.

In fact, the various states regularly make minor changes to the rules. Hundreds of minor adjustments have been made over many decades. While these changes may seem significant, from a broad socio-legal perspective they do little to challenge the status quo.

Playing by the rules?

A GMA-commissioned review by Pegasus Economics last year documented regular instances of duck shooters behaving irresponsibly. The independent report concluded that “non-compliance with hunting laws is commonplace and widespread”.

The ABC has aired allegations that unsustainable hunting is on the rise and that regulators feel unable to enforce the rules. It revealed pits containing around 200 unrecovered shot birds from the 2017 opening weekend at Victoria’s Koorangie State Game Reserve alone.

Activists interviewed in the report claimed to have brought out 1,500 dead birds from the wetlands. Of these, 296 were protected species, including 68 endangered Freckled Ducks.

In my book Animals, Equality and Democracy, I argue that there is a generalised tendency for animal welfare laws to be more effective for socially visible animals. Laws that govern the welfare of zoo animals have improved much more quickly, for example, than those that cover animal welfare in factory farms.

Duck shooting is not a highly visible cause of animal harm. Relatively few people live near the wetlands where shooting takes place. But animal advocates have been effective in making it visible, despite laws that limit their ability to do so.

Elaborate events such as Duck Lake, in which animal activists performed their own version of Swan Lake on the opening morning of the 2016 Tasmanian duck shooting season, help generate media attention.

In 2017, long-time Victorian anti-duck-shooting campaigner Laurie Levy from the Coalition Against Duck Shooting was once again fined for entering the water to help an injured bird. While such activities go some way in generating public visibility, they have thus far not been able to stop duck shooting outright.

The gun lobby’s growing influence in Australia

At present, only 28,000 Australians are registered duck shooters. According to 2012 Australia Institute analysis, 87% of Australians support a ban on duck shooting. There is mounting evidence that endangered and non-game species are also being killed.

Before being re-elected at this month’s Tasmanian state election, the Liberal state government promised to soften the state’s gun laws. It also committed to “always protect the right of Tasmanians to safely and responsibly go recreational shooting”.

In Victoria the picture is a little more complex. A 2016 report asserted that most members of the state’s Labor Party oppose duck shooting and that the Andrews government’s continued support may cost it votes.

Indeed, despite the pressure from within the ALP, the daily bag limit for the 2018 season is ten, compared with just four in 2016.

‘Industry capture’ reinvigorating duck shooting

The Pegasus Economics review identifies “industry capture” as a significant factor in the continuation of duck hunting. Industry capture refers to a situation in which industry has a disproportionately close and influential relationship with policymakers compared with other relevant stakeholders.

The decision by the Tasmanian Liberal Party to share details of its proposed softened gun laws with shooters and farmers, and not other interested parties or the public, suggests industry capture is a genuine factor in Tasmania too.

The ConversationWith widespread community opposition ranged against the entrenched interests of the shooters themselves, state governments will need to make some big calls on the future of duck hunting, rather than the current tinkering around the edges.

Siobhan O’Sullivan, Senior Lecturer in Social Policy, UNSW

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


‘Epic Duck Challenge’ shows drones can outdo people at surveying wildlife

File 20180119 80171 5jolfq.jpg?ixlib=rb 1.1
A drone image of a breeding colony of Greater Crested Terns. Researchers used plastic bird decoys to replicate this species in an experiment that compared different ways of counting wildlife.
Jarrod Hodgson, CC BY-ND

Jarrod Hodgson, University of Adelaide; Aleks Terauds, and Lian Pin Koh, University of Adelaide

Ecologists are increasingly using drones to gather data. Scientists have used remotely piloted aircraft to estimate the health of fragile polar mosses, to measure and predict the mass of leopard seals, and even to collect whale snot. Drones have also been labelled as game-changers for wildlife population monitoring.

But once the take-off dust settles, how do we know if drones produce accurate data? Perhaps even more importantly, how do the data compare to those gathered using a traditional ground-based approach?

To answer these questions we created the #EpicDuckChallenge, which involved deploying thousands of plastic replica ducks on an Adelaide beach, and then testing various methods of tallying them up.

As we report today in the journal Methods in Ecology and Evolution, drones do indeed generate accurate wildlife population data – even more accurate, in fact, than those collected the old-fashioned way.

Jarrod Hodgson standing in one of the replica colonies of seabirds constructed for the #EpicDuckChallenge.
S. Andriolo

Assessing the accuracy of wildlife count data is hard. We can’t be sure of the true number of animals present in a group of wild animals. So, to overcome this uncertainty, we created life-sized, replica seabird colonies, each with a known number of individuals.

From the optimum vantage and in ideal weather conditions, experienced wildlife spotters independently counted the colonies from the ground using binoculars and telescopes. At the same time, a drone captured photographs of each colony from a range of heights. Citizen scientists then used these images to tally the number of animals they could see.

Counts of birds in drone-derived imagery were better than those made by wildlife observers on the ground. The drone approach was more precise and more accurate – it produced counts that were consistently closer to the true number of individuals.

Comparing the vantages: drone-derived photographs and the ground counter’s view.
J. Hodgson

The difference between the results was not trivial. Drone-derived data were between 43% and 96% more accurate than ground counts. The variation was due to how many pixels represented each bird, which in turn is related to the height that the drone was flown and the resolution of the camera.

This wasn’t a surprise. The experienced ground counters did well, but the drone’s vantage point was superior. Observing photos taken from above meant the citizen scientists did not have to contend with obscured birds that often occur during ground counts. The imagery also benefited the citizen scientists as they could digitally review their counts as many times as they needed. This reduced the likelihood of both missing an individual and counting an individual more than once.

The scientists were assisted by many volunteers, without whom the #EpicDuckChallenge would not have been possible.
J. Hodgson

However, even though it proved to be more accurate, making manual digital counts is still tedious and time-consuming. To address this, we developed a computer algorithm in the hope that it could further improve efficiency without diminishing data quality. And it did.

We delineated a proportion of birds in each colony to train the algorithm to recognise how the animal of interest appeared in the imagery. We found that using 10% training data was sufficient to produce a colony count that was comparable to that of a human reviewing the entire scene.

This computerisation can reduce the time needed to process data, providing the opportunity to cut the costs and resources needed to survey wildlife populations. When combined with the efficiencies drones provide for surveying sites that are hard to access on foot, these savings may be considerable.

Using drone monitoring in the field

Our results have important implications for a range of species. We think they are especially relevant to aggregating birds, including seabirds like albatrosses, surface nesting penguins and frigatebirds, as well as colonial nesting waterbirds like pelicans.

Other types of animals that are easily seen from above, including hauled-out seals and dugongs, are highly suited to drone monitoring. The nests or tracks of animals, such as orangutans and turtles, can also be used to infer presence.

Additional experiments will be useful to assess the ability of drones to survey animals that prefer to stay hidden and those within complex habitats. Such assessments are of interest to us, and researchers around the globe, with current investigations focused on wildlife such as arboreal mammals and cetaceans.

We are still learning about how wildlife react to the presence of drones, and more research is required to quantify these responses in a range of species and environments. The results will help to refine and improve drone monitoring protocols so that drones have minimal impact on wildlife. This is particularly important for species that are prone to disturbance, and where close proximity is not possible or desirable.

Read more:
How drones can help fight the war on shark attacks

The world is rapidly changing, with many negative outcomes for wildlife. Technology like drones can help scientists and managers gather data fast enough to enable timely assessment of the implications of these changes.

The ConversationWhen monitoring wildlife, increasing the accuracy and precision of animal surveys gives us more confidence in our population estimates. This provides a stronger evidence base on which to make management decisions or policy changes. For species and ecosystems threatened with extinction or irreparable damage, such speedy action could be a literal lifeline.

Jarrod Hodgson, PhD Candidate, University of Adelaide; Aleks Terauds, Senior Research Scientist / Section Head, and Lian Pin Koh, Professor, University of Adelaide

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

Why we shouldn’t be too quick to blame migratory animals for global disease

Alice Risely, Deakin University; Bethany J Hoye, University of Wollongong, and Marcel Klaassen, Deakin University

Have you ever got on a flight and the person next to you started sneezing? With 37 million scheduled flights transporting people around the world each year, you might think that the viruses and other germs carried by travellers would be getting a free ride to new pastures, infecting people as they go.

Yet pathogenic microbes are surprisingly bad at expanding their range by hitching rides on planes. Microbes find it difficult to thrive when taken out of their ecological comfort zone; Bali might just be a tad too hot for a Tasmanian parasite to handle.

But humans aren’t the only species to go global with their parasites. Billions of animals have been flying, swimming and running around the globe every year on their seasonal migrations, long before the age of the aeroplane. The question is, are they picking up new pathogens on their journeys? And if they are, are they transporting them across the world?

Read more: A tale of three mosquitoes: how a warming world could spread disease

Migratory animals are the usual suspects for disease spread

With the rate of zoonotic diseases (pathogens that jump from animals to humans) on the rise, migratory animals have been under increasing suspicion of aiding the spread of devastating diseases such as bird flu, Lyme disease, and even Ebola.

These suspicions are bad for migrating animals, because they are often killed in large numbers when considered a disease threat. They are also bad for humans, because blaming animals may obscure other important factors in disease spread, such as animal trade. So what’s going on?

Despite the logical link between animal migration and the spread of their pathogens, there is in fact surprisingly little direct evidence that migrants frequently spread pathogens long distances.

This is because migratory animals are notoriously hard for scientists to track. Their movements make them difficult to test for infections over the vast areas that they occupy.

But other theories exist that explain the lack of direct evidence for migrants spreading pathogens. One is that, unlike humans who just have to jump on a plane, migratory animals must work exceptionally hard to travel. Flying from Australia to Siberia is no easy feat for a tiny migratory bird, nor is swimming between the poles for giant whales. Human athletes are less likely to finish a race if battling infections, and likewise, migrant animals may have to be at the peak of health if they are to survive such gruelling journeys. Sick travellers may succumb to infection before they, or their parasitic hitchhikers, reach their final destination.

Put simply, if a sick animal can’t migrate, then neither can its parasites.

On the other hand, migrants have been doing this for millennia. It is possible they have adapted to such challenges, keeping pace in the evolutionary arms race against pathogens and able to migrate even while infected. In this case, pathogens may be more successful at spreading around the world on the backs of their hosts. But which theory does the evidence support?

Sick animals can still spread disease

To try and get to the bottom of this question, we identified as many studies testing this hypothesis as we could, extracted their data, and combined them to look for any overarching patterns.

We found that infected migrants across species definitely felt the cost of being sick: they tended to be in poorer condition, didn’t travel as far, migrated later, and had lower chances of survival. However, infection affected these traits differently. Movement was hit hardest by infection, but survival was only weakly impacted. Infected migrants may not die as they migrate, but perhaps they restrict long-distance movements to save energy.

So pathogens seem to pose some costs on their migratory hosts, which would reduce the chances of migrants spreading pathogens, but perhaps not enough of a cost to eliminate the risk completely.

Read more: Giant marsupials once migrated across an Australian Ice Age landscape

But an important piece of the puzzle is still missing. In humans, travelling increases our risk of getting ill because we come into contact with new germs that our immune system has never encountered before. Are migrants also more susceptible to unfamiliar microbes as they travel to new locations, or have they adapted to this as well?

Guts of migrants resistant to microbial invasion

To investigate the susceptibility of migrants, we went in a different direction and decided to look at the gut bacteria of migratory shorebirds – grey, unassuming birds that forage on beaches or near water, and that undergo some of the longest and fastest migrations in the animal kingdom.

Most animals have hundreds of bacterial species living in their guts, which help break down nutrients and fight off potential pathogens. Every new microbe you ingest can only colonise your gut if the environmental conditions are to its liking, and competition with current residents isn’t too high. In some cases, it may thrive so much it becomes an infection.

The Red-necked stint is highly exposed to sediment microbes as it forages for the microscopic invertebrates that fuel its vast migrations.
Author provided

We found the migratory shorebirds we studied were exceptionally good at resisting invasion from ingested microbes, even after flying thousands of kilometres and putting their gut under extreme physiological strain. Birds that had just returned from migration (during which they stopped in many places in China, Japan, and South East Asia), didn’t carry any more species of bacteria than those that had stayed around the same location for a year.

The ConversationAlthough these results need to be tested in other migratory species, our research suggests that, like human air traffic, pathogens might not get such an easy ride on their migratory hosts as we might assume. There is no doubt that migrants are involved in pathogen dispersal to some degree, but there is increasing evidence that we shouldn’t jump the gun when it comes to blaming migrants.

Alice Risely, PhD candidate in Ecology, Deakin University; Bethany J Hoye, Lecturer in Animal Ecology, University of Wollongong, and Marcel Klaassen, Alfred Deakin Professor and Chair in Ecology, Deakin University

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


How Do Parrots Talk?


Penguins under threat from drowning in fishing nets

File 20171130 12029 4drhxl.jpg?ixlib=rb 1.1
Bycatch: penguins can easily drown in nets designed to ensnare fish.
NZ Ministry of Fisheries

Ursula Ellenberg, La Trobe University

Fishing nets pose a serious risk to the survival of penguin species, according to a new global review of the toll taken by “bycatch” from commercial fishing. Fourteen of the world’s 18 penguin species have been recorded as fishing bycatch.

Among the species under threat are Tasmania’s little penguins and New Zealand’s yellow-eyed penguins, as detailed in a review, published in the journal Endangered Species Research.

The review shows the level of bycatch is of greatest concern for three species: Humboldt and Magellanic penguins, both found in South America, and the endangered New Zealand yellow-eyed penguins.

On New Zealand’s South Island, yellow-eyed penguins are down to fewer than 250 nests. Previous population strongholds have declined by more than 75%. Conservative population models predict local extinction of yellow-eyed penguins by 2060, if not earlier.

Read more: Shrinking Antarctic glaciers could make Adélie penguins unlikely winners from climate change

Penguins are among the world’s most iconic and loved birds, despite the fact that many people never get to see one in the wild. Indeed, the opportunities to do so are diminishing, with ten of the 18 penguin species threatened with extinction. After albatrosses, penguins are the most threatened group of seabirds. And, like albatrosses, bycatch is thought to be a serious issue for some species.

On land, many penguins are now well protected, thanks to the efforts of conservation researchers, government agencies, community groups and tourism operators. Where many penguins were once vulnerable to attack from introduced predators, or to habitat loss from farming or development, today the biggest worry for many penguin chicks is how to get more food out of their parents.

Time to eat yet?

But below the waves it’s a different story. Over thousands of years, these keen-eyed seabirds have evolved to catch food in the depths, while avoiding natural predators such as seals and sharks. But they cannot see the superfine nylon fishing nets invented in the 1950s which fishers now set in penguin foraging areas.

Little penguins, whose scientific name Eudyptula minor literally means “good little diver”, typically forage in the upper 20 metres of the ocean, with each dive lasting about 90 seconds. The larger yellow-eyed penguin – Megadyptes antipodes, the “big diver of the south” – prefers to hunt on the seafloor some 80-90m down, holding their breath for 2-3 minutes before coming up for air. If they do not encounter a fishing net, that is.

Gillnets (also called set nets) in particular are very dangerous for penguins. These nets are set in a stationary position rather than being dragged through the water. They are designed to catch fish around their gills, but can just as easily snare a penguin around its neck.

If it gets tangled in a net, a penguin will panic and drown in minutes. In Tasmania, nets with more than 50 drowned little penguins have been found washed ashore. Other penguins are found on beaches with characteristic bruising from net entanglement around their necks.

Nets are deadly to little penguins.
Eric Woehler, Author provided

When a penguin is killed at sea, this has knock-on effects back at the nest. The chicks will die of hunger or fledge underweight, with little chance of surviving their first year at sea.

The breeding partner left behind will probably skip a breeding season; some penguins never find another partner after losing their mate. I have seen them calling plaintively from their nest, or even going down to the shore in the evening to look out to sea, before returning to their nest all alone.

Declining numbers

In New Zealand, the endangered yellow-eyed penguin is declining. Current population models predict their extinction on the New Zealand mainland by 2060, or potentially even earlier. Yellow-eyed penguins are facing many threats mostly because they are simply living too close to humans.

Whereas threats on land are reasonably well managed, threats at sea need urgent attention. Marine habitat degradation by industries that damage the seafloor will take decades to recover. Similarly, pressures from climate change will not have a quick enough fix to save yellow-eyed penguins from local extinction.

There is one thing, however, we can change immediately: the needless death of penguins in fishing nets. This will give already struggling penguin populations a bit of a breather and maybe even the resilience required to deal with the many threats they face in their daily fight for survival.

Read more: New behaviour leaves Antarctic penguins on the shelf

Judging by the number of penguins washed ashore with net injuries, many fishers simply discard penguins’ carcasses at sea rather than reporting bycatch or working towards solutions to mitigate it.

Do we really want penguins to drown for our treat of fish and chips? Less destructive fishing methods are available that do not cause penguin bycatch and the death of other protected species.

But these more selective fishing methods would require fishers to change gear, which costs money. Currently, there is very little legal or commercial incentive for fishers to do anything about penguin bycatch.

The ConversationBut there are a couple of things you can do. Please do not just buy any fish with your chips – ask which species it is and how it has been caught. You can use a sustainable seafood guide, such as New Zealand’s Best Fish Guide or Australia’s Sustainable Seafood Guide. That way you can help the penguins snag a safe fish supper of their own.

Ursula Ellenberg, Honorary Lecturer, La Trobe University

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


Those noisy crested pigeons use their unique feathers to sound an alarm

File 20171108 6733 aiwxzv.jpg?ixlib=rb 1.1
Crested pigeon in flight with the primary feathers spread and the narrow eighth primary is visible.
Geoffrey Dabb, Author provided

Trevor Murray, Australian National University

Crested pigeons are a common sight in many Australian backyards, and are noted for the rapid trilling sound they make when they take flight.

In our research, published today in Current Biology, we show that these sounds are produced by feathers in the wings that have evolved to communicate about danger.

Recording of a pigeon fleeing from a predator.
Trevor Murray, Author provided36.4 KB (download)

These sounds were long suspected of being produced by the wings, so we used high-speed video and acoustic recording to investigate this.

Read more: Citizen scientists count nearly 2 million birds and reveal a possible kookaburra decline

The key finding is that a pair of unusual primary flight feathers, half the width of the others, produce a high-pitched sound as the wing pushes down through the air. This sound is a critical part of the alarm signal that warns the flock.

The wing of a crested pigeon showing the thinner 8th primary feather.
Trevor Murray, Robert Magrath and Jochen Zeil, Author provided

No other related pigeon species has these unusually narrow wing feathers. The narrowness of these feathers, known as the the 8th primary feathers, suggests that they have evolved to produce this high-pitched sound.

Feathers to the test

We discovered that the 8th primary feathers produce the high-pitched sound, by trimming pairs of feathers and recording the sounds of pigeons fleeing. But we were also interested in how trimming the 8th primary feathers would affect the response of other crested pigeons that heard these modified fleeing sounds.

We developed a speaker set up that let us broadcast the recorded fleeing sounds of birds from the side of a vehicle. We would then drive next to pigeons foraging in parks and on nature strips around Canberra, and broadcast one of the recordings at random.

Recording of a pigeon released after capture with both 8th primaries removed.
Trevor Murray, Author provided61.6 KB (download)

When we played recordings of crested pigeons with both the 8th primary feathers removed, the birds looked up, but almost never flew off.

Our suspicions were correct – this unusual pair of 8th primary feathers and their high-pitched sound were necessary for warning other pigeons to flee.

So what about the neighbouring 9th primary feathers? We discovered that these produce a low-pitched sound during take-off.

Recording of a pigeon released after capture with both 9th primaries removed.
Trevor Murray, Author provided52.2 KB (download)

When we played recordings of crested pigeons with both the 9th primary feathers removed, the birds flew off just as often as if they’d heard an alarm. These feathers were not necessary for warning flock mates.

All in a flap

Signals evolve when the creature producing the signal and the one responding to it both benefit.

Crested pigeons that see predators can benefit by inciting the rest of the flock to flee with them, much like redshanks and Belding’s ground squirrels, whose coordinated fleeing confuses predators.

A pair of crested pigeons on the ground.
Geoffrey Dabb, Author provided

The benefit from communication to every individual could explain why the 8th primary is so unique – it has evolved to exaggerate the sounds of fleeing to trigger a coordinated response.

While these pigeons always produce some sound when they take off, the sounds produced when fleeing danger are distinct. They are louder and have a higher tempo.

A crested pigeon takes flight in slow motion.

Footage from high-speed video cameras showed that fleeing pigeons flap faster when trying to escape a threat. Flapping faster speeds up their escape and it also increases the tempo of the sound, thus transforming the take-off sound into an alarm.

While these differences in the sound can be quite subtle to the human ear, crested pigeons are able to respond to them in about a third of a second. (Can you tell the difference between these two sounds?)

Recording of a pigeon take-off normally from a feeder.
Trevor Murray, Author provided32.7 KB (download)

Recording of a pigeon fleeing from a predator.
Trevor Murray, Author provided36.4 KB (download)

All animals produce some sound as they move, and these sounds are intrinsically informative. They tell the listener where the individual is and how it is moving. This is in stark contrast to the sounds produced by our voices, which are not the result of specific actions.

The same is true for animals: vocal calls are notoriously unreliable, even being used deceptively to steal food. Africa’s fork-tailed drogos, for example, often use their own, and even other species, vocal alarms to scare competitors away and steal their food.

Non-vocal sounds, by comparison, are unable to be faked. If a crested pigeon flees it cannot help but warn its flock mates, just as it cannot warn its flock mates without fleeing.

This means that these non-vocal alarms are a very reliable indicator of danger – and, more broadly, that non-vocal sounds produced by movement are intrinsically informative and so are likely to evolve for communication.

Other feathered messages

Crested pigeons aren’t the only birds that use their feathers to communicate. We know of several other pigeon species that produce conspicuous sounds with their wings that are just waiting to be investigated, such as the Spinifex pigeon.

Spinifex pigeon in the Northern Territory.
Flickr/Kristian Golding, CC BY-NC-ND

Mourning doves and zenaida doves from the Americas also make sounds, that appear to be produced by their wings, that warn their flock mates of danger.

Read more: New research reveals the origin of Australia’s extinct flightless giants, the mihirung birds

Non-vocal acoustic signals are used in many other groups to maintain territories and attract mates – manakins and hummingbirds being the most widespread examples.

The ConversationIt appears that non-vocal acoustic communication is much more common than most people thought, and so we hope a new generation of curious people are inspired to listen closely to the animals around them and discover even more of these unusual signals.

Trevor Murray, Postdoctoral Scientist, Australian National University

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


Australia: Tasmania – Nest Boxes Save Swift Parrots