Black Rat (Roof Rat)

Where it lives

Roof spaces, false ceilings, wall cavities, palm crowns, citrus and carob trees, warehouses and port buildings. Travels along cables, pipes and walls rather than the ground.

Signs

• Night-time scratching and scurrying overhead in ceilings and roof voids
• Spindle-shaped droppings around 10 mm long in lofts and on beams
• Gnawed fruit left on the tree, hollowed out with the skin intact
• Smear marks along roof timbers, cables and the tops of walls
• Nests of shredded insulation, paper and palm fibre

Risks

• Historic and current vector of serious disease including Salmonella and Leptospirosis
• Damages roof insulation, water tanks and photovoltaic cabling
• Contaminates roof-mounted water storage
• Strips fruit crops and damages palms

Prevention

• Fit mesh to eaves, vents, and gaps where cables enter the roof
• Cut back tree branches at least one metre from the roofline
• Cover roof water tanks and seal overflow pipes with mesh
• Harvest fruit promptly and clear windfall

Treatment

Because black rats travel at height, bait and traps must be placed on their aerial runs (beams, cable trays and roof voids), not on the floor. We proof eaves and service entries, install stations along the runs, and use tracking dust or cameras where activity is hard to confirm.