You can help track 4 billion bogong moths with your smartphone – and save pygmy possums from extinction



Healesville Sanctuary, Werribee Open Range Zoo

Sally Sherwen, University of Melbourne and Therésa Jones, University of Melbourne

Each year, from September to mid-October, the tiny and very precious mountain pygmy-possums arise from their months of hibernation under the snow and begin feasting on billions of bogong moths that migrate from Queensland to Victoria’s alpine region.

But for the past two springs, moth numbers have collapsed from around 4.4 billion in alpine areas to an almost undetectable number of individuals. And the mountain pygmy-possums went hungry, dramatically affecting breeding success among the last remaining 2,000 that live in the wild.




Read more:
Meet the Australian wildlife most threatened by climate change


This year’s migration of bogong moths to the possums’ alpine home is crucial for the critically endangered mountain pygmy-possums. That’s why we’re asking you to do two simple things: turn off your lights at night, and if you see a bogong moth, take a picture.

What’s happened to the moths?

Bogong moths make an epic migration through Australia every spring.
Credit: Donald Hobern

We don’t know exactly why the moths are not making it to their summer alpine destination. It’s likely extreme drought, pesticides and changes in agricultural practices are all major factors. However, scientists believe that because moths use both the Earth’s magnetic field and visual cues on the horizon to navigate, light pollution from urban centres can confuse the moths and stall their journey.

Some of the greatest beacons on their path are Parliament House and Canberra’s bright surrounds. Both parliamentarians and the general public are being asked to turn unnecessary outdoor lights off from September 1 to October 31, as part of the Lights Off for Moths campaign.

Artificial night lighting has dramatically changed the nocturnal environment. In urban environments, the soft glow of moonlight is overpowered by bright streetlights, security lights and car headlamps. These light sources can be more than 1,000 times as bright as moonlight, and their biological impact is increasingly visible and widespread.

One of the most obvious impacts of artificial light at night is that it can attract animals (sometimes fatally). While a “moth to a flame” may be somewhat poetic, when one moth becomes hundreds, or potentially thousands, the ecological impact may be catastrophic. Current global lighting practices may be creating this very scenario.

Recent evidence links the presence of artificial light at night with large-scale deaths and shifts in nocturnal migration patterns in birds. In insects, artificial night lighting disrupts nocturnal pollination networks and is strongly linked with observed mass declines in insect (and particularly moth) populations.

No moths means hungry possums

When a species like bogong moths decline, it has huge ramifications. Insects in particular are vital pillars supporting whole ecosystems – without bees and other insect pollinators, for example, we risk the extinction of our flowering plants. Many birds, reptiles and mammals depend on insects as part of their diet.

Tiny mountain pygmy possums, like many other animals, depend on the annual bogong moth migration for food.
Tim Bawden

For mountain pygmy possums, the fatty, nutrient-rich bounty of bogong moths arrives right as they are waking up in the spring. They are one of the only Australian mammals that hibernate, and can spend up to seven months sleeping under the alpine snow.

The possums awake ravenously hungry, and devour the bogong moths to regain crucial fat stores. Without the moths there at the right time, the possums struggle to secure enough energy to breed successfully.

Snap that moth

Alongside the Lights Off for Moths campaign, Zoos Victoria has launched Moth Tracker, an app that allows Australians to photograph and log any potential sightings of migrating bogong moths.

Moth Tracker, which can be accessed through any laptop or smartphone, is adapted from the popular Southern Right Whale watching app in collaboration with Federation University and Victorian conversation network SWIFFT.

Bogong moths migrate from their winter breeding grounds throughout Queensland, New South Wales and western Victoria in search of cooler climates for the spring and summer in the Victorian and NSW Alpine regions where the mountain pygmy-possums live.

Before they become moths, the larvae look like tiny, shiny brown capsules and are commonly referred to as cutworm. Migratory bogong moths are dark brown, with two lighter spots on each wing. They are small, only about the length of a paper clip. During the day they’re often seen grouped together like roof tiles. At night, they are more active and flying around.

If you see a bogong moth (or something you think might be a bogong month), we need you to take a photograph and log the location, day and time with Moth Tracker. Scientists will use the data to determine whether any moths are making their way to the precious, and very hungry, possums that are just starting to wake from their winter hibernation.




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The Victorian Mountain Pygmy-possum Recovery Team, together with partner organisations, is also investigating options for interventions in the wild if needed. These may include a world-first airdropping of “bogong balls” to feed the hungry possums, as well as improving habitat connectivity and captive measures to support populations through the breeding season.

But with unnecessary outdoor lights switched off and citizen scientists looking out for bogong moths, there is still hope for the mountain pygmy-possums.The Conversation

Sally Sherwen, Director Wildlife Conservation and Science, Zoos Victoria, University of Melbourne and Therésa Jones, Lecturer in Evolution and Behaviour, University of Melbourne

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

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Explainer: what is tularemia and can I catch it from a possum?


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Researchers have found Australia’s first confirmed case of tularemia in a ringtail possum.
Andrew Mercer/flickr, CC BY-NC-SA

John-Sebastian Eden, University of Sydney

Tularemia is a disease that affects humans and other animals. It is caused by infection with the bacterium Francisella tularensis and is commonly spread by biting insects or by direct contact with an infected animal.

Human infection is less common than infection in small animals like rabbits and rodents. But it is important human cases are recognised and diagnosed quickly because without appropriate treatment the disease can be life-threatening.

Our team has recently confirmed its presence in Australia in samples taken from ringtail possums who died in two outbreaks in early 2000.

While this is clearly a newly identified risk to public health, it’s important to recognise how rare the disease is and how well the infection responds to treatment.

How is it transmitted to humans?

Tularemia is a “zoonotic disease”, an animal disease that can be transmitted to humans. The most common way someone might be infected is by being directly exposed to an infected animal through a bite or scratch, or even handling infected tissue, like when hunters skin animals.


Further reading: First Hendra, now bat lyssavirus, so what are zoonotic diseases?


Human infections can also occur indirectly from an animal through a biting insect vector, like ticks or deer flies. So, a fly might feed on an infected animal then also bite a human, transferring the bacterium via its mouth parts.

Humans can also catch the disease from animals by coming into contact with environmental sources such as water or soil that have been contaminated by an infected carcass. The bacteria might then infect humans through the eye, or an open wound, or even if digested from contaminated food.

How rare is tularemia in humans?

Fortunately, human cases of tularemia are relatively rare and appear to be limited to the Northern Hemisphere. Yet, even in the US, where the disease is well described, human cases rarely exceed 100-200 a year.

Australia has long been considered tularemia-free. So, it was surprising when, in 2011, two human cases were reported in Tasmania after exposure to ringtail possums.

While diagnostic tests on the patients’ samples suggested an infection with the bacterium, no samples were obtained from the offending possums to corroborate the unusual infection.

More importantly, researchers couldn’t grow and isolate the bacteria from any of the patients’ samples. Follow-up surveys of native animals in the area failed to detect the organism. So, the story of tularemia in Australia had, until recently, remained somewhat of a mystery.

How can I protect myself?

While our study has confirmed the presence of tularemia in Australia and identified ringtail possums as a reservoir for the disease, no-one knows if it’s present in other wildlife along the east coast.


Further reading: Bites and parasites: vector-borne diseases and the bugs spreading them


So, to minimise the chances of infection, take care when handling sick, distressed or dead animals. Similarly, when travelling in an area with ticks or other biting insects, wear protective clothing and repellents.

How do I know if I’m infected?

In humans, tularaemia symptoms can vary but typically depend on how someone was exposed.

An ulcer forms at the site of infection, like this one on someone’s hand.
CDC Public Health Image Library/Wikimedia

The most common form of disease in humans is known as ulceroglandular tularemia, which develops after an infected animal or insect bites or wounds you. As the name suggests, you develop a sudden fever, an ulcer forms at the site of infection, and the lymph glands near the wound swell.

Another and perhaps more serious form of the disease is pneumonic tularemia. This can occur when you breathe in bacteria from contaminated dust or aerosols, and your lungs become infected. Symptoms include cough, chest pain and difficulty breathing, and can be difficult to treat.

Yes, it can be treated

While infection can potentially cause severe disease and can kill, timely treatment with commonly available antibiotics should clear the infection. However, it is important the disease is correctly diagnosed as the most effective antibiotics (such as streptomycin) are often different to those used to treat other bacterial skin or wound infections.

There have been no reported cases of humans infecting other humans. While being exposed to someone infected with tularemia might pose some risk, the rarity of the cases and the effectiveness of antibiotic treatments to control the infection minimise this.

Looking to the future

What our study highlights more than anything is the need to investigate wildlife disease to understand potential risks to our environment and our own health.

So, we plan to conduct further surveys of animal and tick-borne diseases to explore undiscovered pathogens that may affect public health or impact our native animal populations.

We are also applying the same technology used to confirm the presence of tularemia in Australian wildlife for the first time to investigate other cold cases of the animal disease world – neglected and undiagnosed animal diseases.

We do this using a powerful technique called “RNA-Seq”, short for RNA sequencing, to analyse samples. With RNA-Seq, there’s no need to know what diseases might be present; researchers sequence all the genetic material in the sample, whether it has come from a host such as a human or animal, or from an infecting organism such as a virus, bacteria, or parasite.

This “metagenome” data is then pieced together and compared to databases containing genome data from previously sequenced pathogens.

The ConversationThrough these studies, we hope to reveal the full diversity of pathogens present in our native wildlife, and particularly, those that sit at the human-animal interface, a fault line that allows microbes to flow from one host to another. Most novel emerging diseases are spill-overs from zoonotic sources, so this research is critical for human health.

John-Sebastian Eden, NHMRC early career fellow, Faculty of Science, University of Sydney

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

Hidden housemates: when possums go bump in the night


Emma Power, Western Sydney University and Jane DeGabriel, Western Sydney University

You’re drifting off to sleep when, suddenly, there’s a bump and a thump and an unearthly shriek. But never fear, if your home is making these noises you probably don’t have ghosts, but a family of common brushtail possums.

Researchers have documented 18 different brushtail possum sounds. These include “grunting, growling, hissing, screeching, clicking and teeth-chattering calls, many of which would not be out of place on a horror movie soundtrack”.

Common brushtail possums (Trichosurus vulpecula) live across much of suburban Australia. Although often associated with bushland environments and commonly considered a tree-dweller, these adaptable creatures are also highly attracted to human houses.

The biggest hidden housemate?

Despite being the same size as a domestic cat, these lively, nocturnal marsupials frequently make their dens in the ceiling and wall cavities of homes. In fact, one study of possums in urban Tasmania found that 87% of their visits to dens were associated with buildings (mostly older houses), while 45% of den visits were to roof cavities.

These hidden animals make themselves known to their human housemates as they run across the ceiling. A Sydney study found that as many as 67% of people whose properties were visited by possums heard possum activity on or in roof cavities, while 58% reported possums living in these spaces.

A young possum discovers pineapple, via mum.
Peter Firminger/Flickr, CC BY

Possums in the city

At the time of European arrival, common brushtail possums were abundant across mainland Australia and Tasmania. However, intensive hunting for a burgeoning fur trade in the 19th and early 20th centuries led to a drastic decline in possum numbers. Since the end of hunting, habitat degradation and fragmentation, fires and fox predation have put further pressure on possum populations. In contrast, they appear to be flourishing in our cities.

Common brushtail possums are territorial creatures, usually sleeping alone during the day in dens in tree hollows, rock piles or logs. Dens are often in limited supply in the bush and possums will compete for nesting sites, sometimes fighting to the death. In contrast, suburbia provides an abundance of potential nesting spaces.

In fact, urban possums seem to prefer living in human-built structures, even when hollow trees are available. A single roof can provide a home for many cohabiting possums, although disputes among roommates may become raucous.

Abundant food and a broad palate mean people and possums were made for each other.
Peter Firminger/Flickr, CC BY

Another reason that brushtail possums have adapted so successfully to our cities is their generalised diet. Unlike specialised eucalypt feeders like the koala, brushtail possums eat the leaves, flowers and fruit of a range of native and exotic plants, as well as Eucalyptus leaves. They also sometimes eat insects and bird eggs.

Thus suburban gardens, with their abundance of fruit trees, roses and vegie patches, provide a “possum supermarket”, conveniently offering a diverse array of tasty, nutritious foods year round – much to the frustration of many gardeners!

In a study in eucalypt woodlands in north Queensland, Jane and her colleagues showed that female possums with access to the greatest amounts of available protein within their home ranges were more likely to breed twice, rather than just once per year.

Eucalypts are generally a poor source of protein and this is likely to limit populations of possums in natural bushland. However, given the abundance of high-quality food sources and limitless den sites in urban environments, it is not surprising that common brushtail possums seem to thrive there.

A possum in the roof!

People who share their homes with possums describe hearing them walking around the roof cavity. Emma’s research heard residents speak about the “thump, thump, thump” of possums walking across the ceiling. Others described being jolted awake at dawn to crashing and scraping sounds, and a feeling that someone was in the house. Some people admitted thinking their house was haunted, a feeling that was triggered by night-time noises coming from hidden spaces.

Hello, possum.
play4smee/Flickr, CC BY-NC

Many people enjoy living with possums, because they feel like it connects them to a time before Australia was urbanised. Some people also value personal connections with possums, becoming familiar with the individuals that share their garden – even giving them names and pointing them out to visitors.

However, people also often describe possums as a pest. They complain about the noise and damage that possums can cause. Damage to ceiling cavities, urine stains and odours in the ceiling are reported, and some people experience possums dying in the ceiling. These rotting bodies can be overwhelmingly smelly and extremely difficult to find.

It is interesting that many people both value possums and find them to be a pest. This is evidence of the complicated relationship that we have with native animals that live inside our homes. We enjoy their wildness, but are also challenged by the way that they make our homes a little bit less human and a little bit closer to nature.

Living well with common brushtail possums

Despite the fact that some people are less keen on house-sharing with possums, they are protected under the wildlife acts of most states in Australia. Although these laws vary, they generally require that residents seek a licence before trapping or moving a possum.

In New South Wales the relevant law is the National Parks and Wildlife Act 1974. If a possum is living in your ceiling, in NSW you can apply to the Office of Environment and Heritage (OEH) for a licence to trap it. Possums must be trapped humanely and released on the property where they were found within 150 m of the place where they were caught.

Note, however: possums moved outside of their home range typically die. They are also usually replaced within four weeks by another possum that moves into their territory.

The OEH suggests that people live alongside possums that share their garden, explaining that “if you encourage a possum to stay around and claim your yard as its territory, other possums will be discouraged from taking up residence”. The OEH also recommends installing nest boxes in trees away from the house to discourage possums from nesting in roofs, and carrying out repairs to close up any holes after possums are removed.

Wildlife protection laws mean that common brushtail possums have a right to live in urban Australia. This means that we need to learn to live well together.

This article is part of a series profiling our “hidden housemates”. Are you a researcher with an idea for a “hidden housemates” story? Get in touch.

The Conversation

Emma Power, Senior Research Fellow, Geography and Urban Studies, Western Sydney University and Jane DeGabriel, Research Fellow in Ecology, Hawkesbury Institute for the Environment, Western Sydney University

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