The great moth revival: how bogongs have bounced back
News Source
โขThu, 22 Oct 2026 14:00:36 GMT
๐ฐ What Happened
Bogong moths are back in huge numbers on Australia's east coast. People in Sydney, Melbourne and other eastern areas have seen them swarm around streetlights this spring. Citizen scientists have logged thousands of sightings on iNaturalist through a project called Bogong Watch. Every dot on the map is one sighting, which may be one moth or many.
Experts say the citizen data clearly shows the population has exploded this year. But they warn the counts can be skewed. More people may simply be looking and posting than in past years. Official surveys run by ecologists have not yet reported their figures.
๐ The Backstory
Bogongs were once so common they numbered in the billions. Up to 4 billion flew to the Australian Alps each summer to rest in cool caves. They caused panic at the Sydney Olympics closing ceremony in 2000. They also invaded Parliament House in Canberra every year.
Numbers fell slowly from 1980 to 2016, then crashed in the summer of 2017. Moths became almost impossible to find in the alpine areas. Ecologist Ken Green, who has tracked them for more than 40 years, said drought from 2017 to 2019 was likely the main cause. Pesticides and city lights played a part too.
๐ฏ Why It Matters
The moths pollinate plants and feed endangered animals like the mountain pygmy possum. More moths means healthier food chains across the Alps.
Bogong moths are back in huge numbers on Australia's east coast. People in Sydney, Melbourne and other eastern areas have seen them swarm around streetlights this spring. Citizen scientists have logged thousands of sightings on iNaturalist through a project called Bogong Watch. Every dot on the map is one sighting, which may be one moth or many.
Experts say the citizen data clearly shows the population has exploded this year. But they warn the counts can be skewed. More people may simply be looking and posting than in past years. Official surveys run by ecologists have not yet reported their figures.
Bogongs were once so common they numbered in the billions. Up to 4 billion flew to the Australian Alps each summer to rest in cool caves. They caused panic at the Sydney Olympics closing ceremony in 2000. They also invaded Parliament House in Canberra every year.
Numbers fell slowly from 1980 to 2016, then crashed in the summer of 2017. Moths became almost impossible to find in the alpine areas. Ecologist Ken Green, who has tracked them for more than 40 years, said drought from 2017 to 2019 was likely the main cause. Pesticides and city lights played a part too.
The moths pollinate plants and feed endangered animals like the mountain pygmy possum. More moths means healthier food chains across the Alps.