Bogong Moths Cause Radar Confusion in Australia

Swarming bogong moths have caused widespread confusion across Australia's New South Wales (NSW) Central Coast and Sydney regions, with their massive numbers appearing as rain on weather radar systems.

Residents checking weather apps have observed large cloud formations on their screens, even during periods of clear skies. The Bureau of Meteorology has confirmed that these "phantom rain" signals are not due to malfunctioning equipment but are instead caused by millions of bogong moths.

"It is possible that radars across eastern NSW are detecting bogong moths," the Bureau of Meteorology stated. "The bureau's radars are not malfunctioning… large numbers of insects can look like very light widespread rain, particularly near sunrise and sunset."

The endangered bogong moths undertake an annual migration from inland areas of Queensland, central NSW, and western Victoria to caves in the Australian Alps each spring. They primarily navigate at night using the moon and are sensitive to light pollution.

However, unusually strong winds in September are believed to have blown large numbers of these moths off their usual migratory path, pushing them towards coastal areas including Sydney.

Weather radar technology works by emitting radio waves that bounce off water particles to detect clouds. These waves, however, can also reflect off other objects, such as smoke, ash, birds, and insects.

"We can confirm that there has been increased 'echoes' displaying on radars across eastern NSW that aren't precipitation," the Bureau of Meteorology reported. "Now we can go back through the records as long ago as World War II to look for signatures of big clouds of moths."

Researchers are hopeful that if they can confirm the moth swarms as the cause of these radar anomalies, this data could be crucial in tracking their migration patterns and populations, aiding conservation efforts for the critically endangered bogong moth.

The spring migration is particularly vital for the survival of mountain pygmy-possums, a species that relies on the moths as a food source after waking from hibernation. Zoos Victoria actively tracks the moths' biannual migration and encourages the public to report sightings through its Bogong Moth Tracker website.

Bogong moths are small, typically measuring between 2.5 and 3.5 centimeters in length, and are characterized by dark stripes running down their wings. The public is encouraged to submit photos of any bogong moth sightings to the Zoos Victoria Bogong Moth Tracker to aid in conservation research.