Bogong moth swarms delight NSW residents, raising hopes for species’ revival

SYDNEY, 29 SEPTEMBER 2026 —

Swarms of bogong moths have descended upon New South Wales in unprecedented numbers over the past few days, prompting experts to declare a potential turning point in the recovery of the endangered native insect.

The scale of the migration has been documented through hundreds of posts to the iNaturalist page for Bogong Watch, a citizen science initiative managed by Invertebrates Australia. These reports, submitted over the weekend, highlight a widespread presence of the moths in coastal regions, marking a distinct increase from previous years. The phenomenon coincides with the start of spring, which traditionally initiates the annual migration of the insects.

During this period, vast numbers of bogong moths travel up to 1,000 kilometers to reach a limited number of cool caves in the Australian Alps, where they spend the summer months escaping the heat.

Linnea Emneby, the project manager for Bogong Watch, reported that the initiative’s “sentinels” were recording exceptionally high volumes of the insects. These sentinels are dozens of volunteers positioned in various directions from Mount Kosciuszko who utilize non-lethal bug lanterns to monitor the migration. Emneby noted that three households in New South Wales each reported dozens of moths on Monday, while one sentinel observed more than 200 bogongs on Sunday night.

The intensity of the sightings has led to a surge in data collection, providing researchers with a clearer picture of the current population status.

The ecological and cultural significance of the bogong moth cannot be overstated, according to Emneby. The insects, which are approximately the size of a 50-cent piece and weigh a third of a gram, play a critical role as pollinators. They also serve as a key food source for the critically endangered mountain pygmy possum. This dual importance shows why the recent increase in numbers is viewed as a positive development for the broader ecosystem.

The moths are not merely pests or curiosities but integral components of the Australian alpine environment.

Dr. Marissa Parrott, a reproductive biologist at Zoos Victoria, expressed profound enthusiasm for the current trends. Zoos Victoria operates a separate citizen science program called Moth Tracker, which has also recorded a spike in activity. Parrott stated that the reports have been continuous, noting that one of her team members was in tears with excitement upon reviewing the morning’s data.

She emphasized that while sightings of the endangered moth had increased over the last two years, the current volume has “blown them out of the water.”

Parrott provided specific data points to illustrate the magnitude of the change, stating that in September alone, the number of bogong moth sightings recorded has exceeded the total for all of last year. This statistical leap is being interpreted by researchers as evidence of a stronger recovery for the endangered species.

The geographic distribution of these sightings is currently concentrated in New South Wales and the Australian Capital Territory, with Victoria still lagging behind in reported numbers. Parrott attributed this favorable outcome to “wetter, cooler weather” conditions, which have likely created an optimal environment for the moths’ migration.

The migration patterns of the bogong moth are complex, with the insects moving in waves that take days to weeks to complete their journey to the Alps. Parrott noted that the current swarms represent a return to historical norms, describing the scene as what “should have happened in the past.” Historically, big swarms of moths would pass through major urban centers including Canberra, Sydney, Newcastle, and Melbourne, traversing the south-eastern Australian migratory zones.

The current activity suggests a restoration of these traditional pathways, which had been disrupted by the recent population decline.

The current recovery follows a severe demographic crisis. An estimated 4 billion moths used to arrive in the Alps each year, but the population collapsed catastrophically between 2017 and 2019, with a decline of up to 99.5%. This dramatic drop had raised serious concerns about the long-term viability of the species.

The bogong moth has been listed as endangered by the International Union for the Conservation of Nature since 2021, although it is not currently listed as a threatened species under federal conservation laws. The recent surge in numbers offers a glimmer of hope that the species may be stabilizing after this near-extinction event.

Historical records highlight the sheer scale of bogong moth populations in the past. The insects were once found in such huge numbers that they would periodically swarm into Parliament House in Canberra. A particularly notable incident occurred during the closing ceremony of the Sydney Olympic Games in 2000, when a swarm of bogongs drawn by stadium lights was so massive that weather forecasters initially mistook it for a rain cloud.

These anecdotes serve as a benchmark for the current recovery, illustrating the dramatic difference between the historical abundance and the recent scarcity.

Parrott explained that the moths generally migrate more inland but can alter their routes depending on weather and wind conditions. Data from the Moth Tracker program last year indicated that the insects can even be blown across to New Zealand. The bogong moth is unique in the animal kingdom as the only invertebrate known to navigate using a map of the stars as a compass.

Parrott expressed hope that any individuals blown off course by strong winds would be able to navigate back safely to their intended destinations. This navigational ability is a critical survival trait for the species, allowing them to cover vast distances with precision.

Despite the positive current trends, experts remain cautious about the long-term outlook. Parrott cited the strongest El Niño on record as a cause for concern, noting that the drier and hotter conditions associated with this climate pattern can be detrimental to the moths. While the current numbers are encouraging and worthy of celebration, Parrott stated that there are worries about what might happen over the next couple of years.

The interplay between climate variability and population recovery remains a key area of focus for researchers monitoring the species.

For the public, experts have provided specific guidance on how to interact with the migrating moths. Residents are advised to turn off unnecessary outdoor lights to reduce disorientation, refrain from using insecticides, and upload their sightings to the Moth Tracker or Bogong Watch platforms to aid scientific monitoring. If moths enter homes, Parrott recommended gently placing them back outside.

She emphasized that females can carry up to 2,000 eggs, making every individual moth precious to the species’ recovery.

Parrott also addressed common misconceptions about the insects, noting that they do not cause damage to property or eat clothes. Instead, they pollinate plants as they move through gardens, providing a significant benefit to horticulture.

She described the moths as “gentle, beautiful little animals that will move on on their own.” This perspective encourages a respectful and supportive attitude among the public, fostering a collaborative effort between citizens and scientists to monitor and protect the recovering population. The current migration serves as a reminder of the resilience of native species and the importance of continued observation and conservation efforts.