Bogong Moths Are Swarming Back Across Eastern Australia in Numbers Not Seen in Years
Scientists were thrilled by the return of the endangered migrants, which feed a critically endangered possum, though they say it's too soon to call it a full recovery.
Millions of bogong moths are once again flying across south-eastern Australia, a spectacle not seen since the species crashed about a decade ago, according to AFP reporting published on October 2. To the scientists who study them, the swarms are welcome news.
"There have been happy tears in my office because this is what nature should be." — Marissa Parrott, Zoos Victoria
A remarkable migrant
In a good year, more than four billion bogong moths travel to cool alpine caves in eastern Australia to escape inland heat. A population collapse that began in 2017 reportedly wiped out an estimated 99.5% of them, a decline linked to drought, pesticides and habitat loss. After the crash, Western Sydney University researcher Eleanor Drinkwater said visitors to the caves found "barely any moths."
- Navigation: 2025 research showed the moths steer by the Milky Way, the first invertebrates shown to use celestial navigation over such long journeys
- Why they matter: they are a key food for the critically endangered mountain pygmy possum
What's driving the comeback
Scientists are still working that out. They believe a run of wetter weather helped.
Caution ahead
Researchers are careful not to declare victory. A severe El Niño is forecast to push temperatures up over summer, and Drinkwater said, "we're still worried about them." Whether this is a lasting recovery or a good year is not yet settled, but for now, the sight has made one of Australia's most unusual animals a cause for cheer.
