How to Get Rid of Cluster Flies in House NZ | GotchaPest

Understanding the Cluster Fly Problem

If you have noticed a sudden, buzzing congregation of slow-moving flies on your windowsills or clustering in your attic as the temperature drops, you are likely dealing with cluster flies. In Aotearoa, these insects are a common seasonal annoyance. Unlike common house flies, they don't seek out food scraps; instead, they seek shelter. Understanding their life cycle is the first step in effective cluster fly control.

While they aren't considered dangerous in the way other pests are, they can be a significant nuisance when they emerge in large numbers during those warm, sunny winter days. At GotchaPest, we believe in practical, sustainable solutions to keep your home comfortable. If you're feeling overwhelmed, you can always ask Buzzy for tailored advice on your specific home setup.

How to Identify Cluster Flies

Cluster flies (Pollenia rudis) are slightly larger than the common house fly and have a distinct, golden-yellow dusting of hair on their thorax. When at rest, they overlap their wings, giving them a slightly elongated appearance. The most telling sign is their behaviour: they move sluggishly and often huddle together in groups, usually in quiet, dark spaces like wall cavities, roof spaces, or unused rooms.

If you aren't sure what you are looking at, check out our online learning centre to compare photos of common NZ pests. If you are still in doubt, our pest-intelligence map shows current sightings in your region, which can help confirm if others nearby are seeing similar activity.

Why Flies are a Problem in NZ

In New Zealand, we experience a specific surge of winter flies in NZ as they transition from outdoors to indoors for warmth. While they don't spread disease like filth flies do, their presence in high volumes can lead to secondary issues, such as attracting other insects or simply causing distress to homeowners. Because they hibernate in large groups, you may find yourself dealing with hundreds of flies simultaneously if your home provides the right conditions—specifically, a sunny, north-facing wall or a warm attic space.

How to Get Rid of Cluster Flies

The most effective strategy relies on a combination of prevention and active trapping. Since these flies seek refuge in autumn, the best time to act is before the first frost.

• Seal entry points: Inspect your home for gaps around window frames, eaves, and vents. Using fine mesh or weather stripping can significantly reduce the number of flies that gain access.
• Reduce indoor attraction: While they aren't attracted to food, they love warmth. During winter, try to keep your home well-ventilated during the day.
• Vacuuming: For immediate relief, use a vacuum cleaner to remove clusters from windowsills. Empty the vacuum bag immediately outside to prevent them from crawling back out.
• Deploy traps: For flies already inside, using a targeted cluster fly trap is the smartest way to manage populations without harsh chemicals.

Ready to sort it? Browse our range of effective traps to find the right solution for your home.

Choosing the Right Trap

We advocate for reusable, long-term solutions. Our Reusable Fly Trap is a Kiwi-designed, screw-on bottle trap that provides a reliable way to capture flies without constant plastic waste. It is designed specifically for NZ conditions, making it an excellent choice for homes, farms, or food-prep areas. You can learn more about our philosophy on our Why GotchaPest page.

How to Use Your Trap

Placement is everything. For cluster flies, place your traps in areas where you have observed the most activity—typically near north-facing windows or points of entry like attic vents.

1. Setup: Simply screw the trap onto a standard drink bottle filled with an attractant (like a mix of sugar and water or apple cider vinegar).
2. Maintenance: Check your trap weekly. If it's full, empty it in a compost area and refresh the lure.
3. Cleaning: Because our traps are reusable, a quick rinse with warm soapy water keeps them hygienic and ready for the next season.

Frequently Asked Questions

Do cluster flies bite?

No, cluster flies are harmless to humans and pets. They do not bite, nor do they feed on human food, which makes them a nuisance pest rather than a health hazard.

Are these the same as regular house flies?

Not quite. While they look similar at a glance, they have different behaviours. House flies are attracted to waste and food, whereas cluster flies are purely seeking warmth for hibernation.

When is the best time to start prevention?

Prevention is most effective in late summer and early autumn (March–April), before the flies seek shelter for the winter. However, traps can be used at any time to manage current infestations.

Take Control of Your Home

Dealing with seasonal pests doesn't have to be a battle you face alone. By focusing on smart, reusable tools, you can keep your home clear of cluster flies without relying on toxic sprays. Explore our full range of effective fly control solutions or check where to buy to find a retailer near you. If you still have questions, don't hesitate to ask Buzzy for a bit of extra guidance.