Bogong Moths Once Migrated In Formations Thought To Be Clouds; #s Crashed 99.5 Percent In 2018-19, Not Recovering
The bogong moth was once so abundant it was mistaken for weather. During Sydney’s Olympic Games in 2000, a swarm of bogong moths attracted by stadium lights was so huge that meteorologists mistook it for a rain cloud. But the species known as “deberra” in Taungurung language – an insect with deep cultural and ecological importance, but which is smaller and lighter than a paperclip – has not returned to those numbers since the population collapsed by up to 99.5% in the two years before 2019.
In February the environment minister, Tanya Plibersek, decided against listing the species as threatened under federal conservation laws, citing gaps in data and uncertainties about the moth’s population due to limited monitoring and its migratory nature. The bogong moth has been on the global endangered list compiled by the International Union for the Conservation of Nature since 2021.
Prof Brendan Wintle, a lead councillor at the Biodiversity Council and a conservation ecologist at the University of Melbourne, calls Plibersek’s decision “very disappointing” given that most experts agree the species is in trouble.
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Every spring, bogong moths migrate hundreds of kilometres to escape the summer heat, travelling from low-lying breeding grounds in southern Queensland and western New South Wales and Victoria to mountainous caves and rocky crevices in the Australian Alps. “They do that without ever having done that before,” Wintle says. “It’s quite unique for such a small animal to travel such a long distance.”
While bogong moth numbers have improved, they remain well below levels recorded before the crash. Wintle says the shift from “hyper abundant” to scarce could have catastrophic consequences for alpine ecosystems. The species is under pressure from the climate crisis, he says, and from land clearing for farming. Bogong moths rely on cold temperatures at the top of mountains for a period of dormancy to complete their life cycle. But those places are rapidly warming.
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https://www.theguardian.com/australia-news/2025/apr/09/massive-swarms-of-bogong-moths-once-resembled-rain-clouds-then-their-numbers-crashed-to-earth