Bogong moth migration boosts hope for endangered pygmy possums

Citizen scientists in Victoria, Australia, are tracking a massive migration of bogong moths to the alpine region.

These moths travel more than 1,000 kilometres from their breeding grounds in Queensland, New South Wales, and western Victoria to find mountain caves for the summer. Researchers from Zoos Victoria and Western Sydney University use data from the Moth Tracker project and the iNaturalist website to study these movements.

Recent wet seasons appear to have helped the moth population reach a critical mass after severe droughts in 2017 and 2019 caused the numbers to crash. This increase in moths provides a vital food source for the mountain pygmy possum, a critically endangered animal that emerged from hibernation to find the insects. In previous years, a lack of moths caused many female possums to lose their entire litters of babies.

The public contributes significantly to this research by filming and reporting sightings of the moths. Scientists use these submissions to locate caves where the moths undergo aestivation, a state of summer dormancy. While researchers still do not fully understand why the moths form swirling groups called maelstroms or how they select specific caves, the high volume of volunteer data allows them to monitor the species more effectively than they could alone.