When the nights get colder, the Shire's rats and mice start looking for somewhere warm and dry. Bushland near the Royal National Park and Heathcote National Park, overgrown creek lines along the Woronora River, and waterfront gardens on Port Hacking all support healthy rodent populations. When temperatures drop, a roof void full of insulation looks like a five-star hotel.
Rodents are good at staying out of sight, so most people discover them by their signs. Here are seven to watch for, followed by what you can do about them.
1. Scratching and scurrying at night
The most common complaint is noise in the ceiling or walls after dark, often just as the house goes quiet. Roof rats (black rats) are agile climbers and happily nest in roof spaces. Mice are lighter and quicker, and you'll often hear a faster, pattering sound. Noise from inside walls or under the floor is worth noting too.
2. Droppings
Droppings are the clearest evidence. Mouse droppings are small, about the size of a grain of rice, with pointed ends. Rat droppings are noticeably larger and more capsule-shaped. Check the backs of kitchen cupboards, under the sink, in the pantry, behind the fridge and along roof beams. Wear gloves and avoid sweeping them dry, since that can stir up dust.
3. Gnaw marks
Rodents' teeth never stop growing, so they chew constantly. Look for fresh gnaw marks on food packaging, timber, plastic pipes and storage boxes. Chewed electrical wiring in the roof is the one to worry about most, because it can create a fire risk.
4. Greasy rub marks
Rats tend to use the same routes every night, and the oil and dirt in their fur leaves dark smudges along walls, beams, pipes and entry holes. A dark mark around a gap in the eaves or a hole behind the stove is a strong sign of regular traffic.
5. Nests and shredded material
Rodents build nests from whatever they can shred: insulation, paper, cardboard, fabric and garden material. Torn insulation or a pile of shredded paper in the garage or roof void is a giveaway.
6. A stale, musty smell
A strong musty or ammonia-like smell in a cupboard, ceiling space or garage can point to an established infestation. A sudden bad smell can also mean a rodent has died somewhere out of reach.
7. Your pets are fascinated
Dogs and cats often notice rodents before you do. If the dog keeps staring at one patch of ceiling, or the cat sits watching the gap behind the fridge, take the hint.
Why winter is the busy season
Rodents live outside year-round, but cold weather, rain and less food in the garden push them indoors. Homes close to bushland, creeks or the water often see more activity, and older brick and timber homes tend to have more gaps around the eaves, roof tiles and subfloor.
What you can do right now
- Trim branches and vines that touch the roof, since roof rats use them as bridges.
- Pick up fallen fruit, and don't leave pet food out overnight.
- Keep compost in a sealed bin and store birdseed, pet food and pantry goods in hard containers.
- Clear rubbish, stacked timber and clutter from around the house and under decks.
- Seal gaps around pipes, vents, eaves and doors. Mice can get through gaps not much wider than a pencil, and rats through a gap about the width of your thumb.
- Keep garage doors closed at night.
When to bring in a professional
If you're seeing several signs at once, hearing activity most nights, or finding chewed wiring, it's time for help. Rodents breed quickly, and a small problem in May can be a much bigger one by August. A professional rat and mouse control treatment looks at entry points and nesting areas as well as baiting or trapping, and should include advice for keeping them out once they're gone. Families in the southern suburbs can also look up rodent control in Engadine.
Get ahead of it
Sutherland Shire Pest Control Pro handles rodent problems in homes and businesses throughout the colder months. For pest control Sutherland households can call on before the scratching turns into chewed wiring, phone 02 8360 3033.