When a Sighting Becomes a Problem

The distinction

One Animal Is Not a Population

A single wasp at a window in October is a straggler. One ant on a worktop in May walked in. A spider in the bath in September is looking for a mate. None of those is a reason to ring anyone.

What tells you something is established is not a sighting. It is repetition, pattern and residue — the same thing in the same place at the same time of day, or physical evidence left behind. That is the line, and it is worth knowing because people regularly ring about nothing and equally regularly leave something real for three months.

Residue

What Gets Left Behind

Evidence beats sightings, because it accumulates while you are asleep or out.

• Droppings in a line or a corner. Small, dark, 3 to 6mm and scattered is mice. Larger, 15 to 20mm and grouped is rats. Fine dark specks like coffee grounds in a kitchen is cockroach. Any of these means a population, not a visitor.
• Smear marks. Dark greasy streaks along a pipe, a skirting or a joist are rodent fur against a surface used repeatedly. They take time to form, which is the point.
• Gnawing. Chewed cable, packaging, plastic pipe or timber. Nothing else does this.
• Dark spotting on fabric. On a mattress seam or the piping of a divan, this is bed bugs.
• Fine soil or sand pushed up between paving. Excavated bedding from an ant nest underneath.
• Bald patches in a wool carpet, with fine webbing. Carpet moth larvae, and by this stage the damage is done.

Pattern

Same Place, Same Time

Where there is no residue, timing does the work.

Noise overhead only after dark, stopping at dawn, is a rodent. Daytime noise is a squirrel. A steady line of ants along the same route each morning is a trail running back to a nest outside. Wasps going in and out of one point in a wall, a soffit or the ground all day is a nest at that point — not wasps passing through.

Bites that appear overnight, in a line or a small cluster, on skin that was uncovered in bed, are worth investigating even though bites alone never identify the insect reliably.

Urgency

What Can Wait and What Cannot

Ring today:

• A wasp nest by a door, a path, a play area, or anywhere an allergic person goes.
• Anything at all in a food business — a trail across a preparation surface is a finding on a clock.
• A rat indoors, as opposed to in the garden.
• Gnawed electrical cable.

This week: mice with droppings; bed bugs; fleas; cockroaches; a squirrel in the loft; carpet moth damage found.

Worth a call but not urgent: ants on a worktop; a wasp nest somewhere nobody goes; rats in the garden but not the building; cluster flies.

Everything on the second and third lists gets harder and more expensive with time. None of it gets better on its own, with the honest exception of autumn spiders and cluster flies.

Short answers

Questions, Briefly

Where to go next

The Pages That Answer This