It’s a pattern this possum and this moth have followed for thousands of years. 

But in recent years, there have been far fewer moths to eat. In some caves — where Bogong moths lined the walls in their thousands — there are now none, leaving this little possum hungry and facing an uncertain future.

The moth's migration to these caves is an odyssey that remains a bit of a mystery.

Some research suggests Bogong moths can sense the earth's magnetic field and use it as a compass to keep them on the right flight path during the journey. More recently scientists think the moths might use the stars to find their way. 

Either way, the magnitude of their migration is something of awe. 

Recently, microscopic remains of Bogong moth were found on a 2000-year-old grinding tool in Cloggs Cave on Gunaikurnai Country in East Gippsland. And the name Bogong is apparently derived from the language of the Dhudhuroa Nation of North Eastern Victoria.

From Tumut in the north of the mountains to Bega on the east coast and Gippsland in the south, Aboriginal tribes would celebrate this time, eat and strengthen relationships. 

These ceremonies stopped with colonisation. But the moths continued their journey in the billions.

Just 20 years ago, hundreds of thousands of Bogong moths disrupted the Sydney Olympics when they were attracted to stadium floodlights. And in Canberra, many residents remember how the night air could be thick with Bogong moths getting lost in the city lights on the way to the mountains. 

Yet the Bogong moth was just added to an international red list of threatened species as endangered — it was assessed along with 123 other Australian species, 56 of which are now listed as threatened with extinction.

Australia is already ranked 4th in the world for extinction so this is dire news.

The reason for the moth’s sudden decline is not entirely clear, but scientists believe a mix of extreme droughts, pesticides and changes in agricultural practices may be responsible. 

Climate change is a driving factor too. 

Jesse Wallace who has been studying the Bogong moth explains:

“[The Bogong moth] depends on the cool temperatures at the peaks of the mountains where it goes in summer. That [cooler] area is very small, and it gets smaller and smaller as global temperatures rise.”

“The moths also suffer a lot when there's climactic or weather events … the droughts recently in New South Wales saw a 98% crash in the population of the Bogong moth.”

The Bogong moth is their most important food — the protein rich bodies allow possums to raise healthy babies. As the moths stop coming, the future of the Mountain pygmy possum and all the other animals that feed on the moths like mountain lizards, native broad-toothed rats and spiders are in danger. 

“The Bogong moth’s population crash — and its cascading impact on other species — should concern every Australian,”

says ACF’s nature campaigner Jess Abrahams.

“We all depend on the interconnected web of nature, which gives us drinkable water, pollinated crops and clean air.”

We can’t let the Bogong moth and the Mountain pygmy possum join the growing list of extinctions.

But this story is also bigger than their plight. It is a story of how our unique animals and insects rely on each other. And how the cascade of extinction unfolds too easily when one species is in decline. 

Australia has already signed on to a global declaration committing to reverse biodiversity destruction. This declaration will guide development of the new Global Goals for Nature to be negotiated next year. 

To fulfil the declaration, Australia must agree, along with other nations, to end extinction, protect ecosystems and restore the land we've damaged. And we need to follow through on that in Australia, which means strong national environment laws enforced by an independent regulator, new protected areas and funding for species recovery and ecosystem restoration.

We have a choice: allow animals and insects we know are at risk to become extinct or fund recovery programs that bring threatened species and the ecosystems they depend on, back from the brink.

The five-yearly State of the Environment report is due to be released by the federal government in early 2022 and is expected to reveal even further declines in the health of plants, animals and ecosystems across Australia.

Words by Marian Reid.

Multimedia: Flying moths video: Sarah Rees; Mountain pygmy possum: Jiri Lochman/Lochman Transparencies; Bogong moths: Jean-Paul Ferrero/AUSCAPE, CSIRO Wikimedia CC; Selfwood/Alamy; Mount Bogong Max G/Shutterstock; Mount Kosciuszko Sukhvinder Saggu/Shutterstock.