Bogong Moths in Sydney: What the 2026 Swarm Means for Your Home

Spring in Sydney usually means jacarandas and magpie swoops. Spring 2026 has brought something else: millions of bogong moths, swirling around porch lights across the city in the biggest migration in nearly a decade.

If the moths have found your street (or your living room), here's what's going on, and the sensible way to handle it.

What's happening right now

Since late September, swarms have been reported across the Hawkesbury, the North Shore, the Sutherland Shire, the Blue Mountains, the Illawarra and the South Coast. It's the strongest bogong season since populations crashed by up to 99.5 per cent between 2017 and 2019. Last summer, an estimated four billion moths reached the Australian Alps for their seasonal dormancy, the best return since the crash.

Zoos Victoria's citizen-science project, Moth Tracker, has recorded more sightings this spring than in any previous season: strong evidence the species is recovering.

Why the moths are in Sydney

Every spring, bogong moths migrate up to 1,000 kilometres from breeding grounds in southern Queensland and inland New South Wales to cool alpine caves where they spend the summer. They travel at night and navigate by the stars; research published in 2025 confirmed they use the night sky, including the Milky Way, as a compass.

Two forces steer them off course and into the city. Strong north-westerly winds push them toward the coast, and artificial light overwhelms their navigation: streetlights and porch lights look like stars, so moths spiral around them instead of moving on. Researchers studying this swarm put it simply: the moths aren't trying to get into houses, they're trying to migrate, and the city is in the way.

They're passing through, not moving in. Any one suburb usually hosts them for days to a few weeks before the migration shifts on, though this season has been so large that moths may be present in parts of NSW for several more weeks.

Are they dangerous? Here's what experts say

No. Bogong moths don't bite or sting, can't hurt people or pets, don't eat clothes or food, and don't breed indoors. Wildlife experts, councils and even local police have all made the same point. At their worst they're a nuisance: they land on everything, get into cars and vents, and their wing scales and droppings can mark curtains and light fittings.

Because of that, the guidance from experts and councils is unanimous: don't spray the swarm. Insecticides do nothing about a migration, and the species is still climbing back from a historic crash.

What to do at home

A few simple moves make a real difference while the swarm is in your area:

• Turn off unnecessary outdoor lights, and close curtains after dark so indoor light doesn't spill outside. Light is the single biggest magnet.
• If moths are inside, darken the room and leave one outdoor light on with a door or window cracked open, and they'll drift toward the outside light. A glass and a piece of card is the gentlest way to move individuals out.
• Keep cats indoors during the migration.
• Check flyscreens and cover vents: fewer ways in means fewer moths inside.
• Wipe down windowsills and light fittings where moths collect, before scales and droppings mark surfaces.

There's a long game, too: planting native nectar plants like bottlebrush and grevillea feeds moths on the way through and supports the recovery, without bringing them indoors.

Why the comeback matters

The bogong migration is one of Australia's great natural events. The moths are the main summer food source for the critically endangered mountain pygmy possum (fewer than 2,000 remain), and their arrival in the Alps has been described as the second-largest annual pulse of nutrients into that ecosystem, after the sun.

Bogong moths are also deeply significant across First Nations cultures of south-eastern Australia: summer moth harvests were central to ceremony, trade and law, and cooked moth remains dating back 2,000 years have been found in Victorian caves. Globally the species is listed as endangered, though not yet under Australian federal law.

How we treat bogong moths

Bogong moths don't breed in homes, so treatment focuses on your home rather than the swarm. We treat them with exclusion, control and preventive methods: screening vents, sealing the gaps they slip through, managing the lights that draw them in, and a professional moth repellent treatment around entry points and resting spots. Booked once the migration has moved on, that work gets your home ready before next season. Our moth control service handles exactly that.

And if you're finding small moths in the pantry or flying out of a wardrobe, that's a different story entirely: pantry moths and clothes moths breed indoors and do need treatment, and the same service covers them.

For the insects that genuinely do set up home, we've covered why cockroaches keep coming back and what actually fixes it. And if you're not sure what you're looking at, send us a photo or book a quick visit, and we'll tell you honestly whether anything needs doing.

Quick answers on the moth swarm

How long will the moths stay?

In any one suburb, usually days to a few weeks as the migration moves through. This season is exceptional, so parts of NSW may see them for several weeks yet. They aren't breeding in your home, and they will move on.

Do you treat bogong moths?

Yes. We treat them with exclusion, control and preventive methods, plus a professional moth repellent treatment around entry points and resting spots. It's best booked once the swarm has moved on, so your home is ready before next season.

Are they harmful to pets?

They don't bite or sting, and the expert line is that they can't hurt you or your pets. The one practical pet tip from wildlife authorities: keep cats indoors during the migration.

What about the caterpillars?

The caterpillar stage, known as the black cutworm, lives in soil on inland farmland, where it can damage crops. That's an agricultural story, not a Sydney backyard one: the adults visiting your porch light are harmless, and their larvae won't be developing in your home.

Will they be back next year?

The trend is strongly upward. This is the best season since the crash, and researchers are optimistic about the recovery. Numbers next spring depend on rain and conditions in the inland breeding grounds, so nothing is guaranteed, but the direction of travel is good news.