Reading the Signs: Runs, Smears and Burrows

Reading the Signs: Runs, Smears and Burrows

Rats are creatures of habit, and habit leaves marks. Most of what a technician does on a first visit is read them.

Runs

Rats use the same routes night after night, preferring to travel with one side against something solid rather than across open ground. That habit is why runs are readable.

Outdoors they show as flattened paths through grass and undergrowth, usually following a fence line, a wall or the edge of a border. Indoors they show as tracks through dust in a loft or under a floor, and as droppings arranged in a line rather than scattered.

A run tells you the direction of travel, and followed far enough, it tells you where they are getting in.

Smears

Where a rat squeezes past the same point repeatedly, the grease and dirt in its coat transfers onto the surface. Over weeks that builds into a dark, slightly shiny mark.

Smears turn up at pinch points: the underside of a gap, the edge of a hole, the corner of a doorway, along a pipe where it passes through a wall. They are one of the most useful signs there is, because a smear at the edge of an opening tells you the opening is in use rather than merely present.

Fresh smears are soft and mark your finger. Old ones are dry and flake.

Burrows and holes

Outdoors, a rat burrow entrance is roughly 70–120mm across — a tennis ball will usually go in — usually at the base of something: a wall, a bank, a shed, a tree root, dense planting.

The test for whether it is in use is simple and free. Loosely block the entrance with a ball of soil or crumpled paper and look the next day. If it has been reopened, it is active.

Indoors, gnawed holes at skirting level or through a floor are usually roughly circular with gnawed edges, and they will nearly always have smears and droppings nearby. A hole with no smears is often an old one.

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