Droppings
Rice-grain size (3–8 mm) points to mice; capsule-shaped 10–14 mm to rats; pepper-like specks in kitchens to cockroaches.
The field guide · 12 species
Pest identification, plate by plate
To identify a pest, start with what it leaves behind. Droppings, bite patterns, noises, damage and the time of day you notice it narrow most UK household pests down to one or two species. Match your signs below, open the species page to check sizes and look-alikes, or send us a photo and we'll identify it for free.
Start with the evidence
What are you seeing?
Most people never see the pest itself — they find what it leaves behind. Start here.
Noises in the loft or walls
Light scratching at night: mice. Heavier scrabbling: rats. Running at dawn and dusk: squirrels. Thumping on summer nights in the Chilterns: glis glis.
Bites or itchy welts
Lines or clusters on exposed skin after sleeping suggest bed bugs; small bites around ankles, especially with pets, suggest fleas.
Holes in clothes, rugs or carpets
Irregular holes in wool and silk, often in dark wardrobes, come from clothes moth larvae or the 'woolly bear' larvae of carpet beetles.
Insects flying in and out of a gap
A steady stream of yellow-and-black insects into a soffit, air brick or bush in summer is a wasp nest. Bees should go to a beekeeper, not be destroyed.
Trails of small insects indoors
Black ants marching to food along skirting boards come from a garden nest; fast-running insects that scatter when you switch the light on are likely cockroaches.
Birds nesting or fouling
Droppings on sills, ledges and solar panels, and nesting under panels or in gutters, usually means feral pigeons.
Can't match it?
Send us a photo and we'll identify it free →
The library
Every species we treat
Plate 01
Brown rat
Rattus norvegicus
Plate 02
House mouse
Mus musculus
Plate 03
Common wasp
Vespula vulgaris
Plate 04
Bed bug
Cimex lectularius
Plate 05
German cockroach
Blattella germanica
Plate 06
Black garden ant
Lasius niger
Plate 07
Fig. 7Adult 1–3 mm
Ctenocephalides
felis
Cat flea
Ctenocephalides felis
Plate 08
Fig. 8Wingspan 12–17 mm
Tineola
bisselliella
Common clothes moth
Tineola bisselliella
Plate 09
Fig. 9Adult 1.5–3.5 mm
Anthrenus
verbasci
Varied carpet beetle
Anthrenus verbasci
Plate 10
Fig. 10Body 24–28.5 cm
Sciurus
carolinensis
Grey squirrel
Sciurus carolinensis
Plate 11
Fig. 11Body 12–17.5 cm
Glis
glis
Edible dormouse (glis glis)
Glis glis
Plate 12
Fig. 1231–34 cm long
Columba
livia
Feral pigeon
Columba livia domestica
Free photo identification
Not sure? Send us a photo.
Add a coin or a ruler for scale if you can. We'll reply with what it is, whether it's a problem, and what to do next — whether or not that involves us.
Questions
Identifying pests: common questions
Species guides draw on the NHS, HSE, BPCA and the Natural History Museum — sources are listed on each page.
How do I identify a bug in my house?
Note its size in millimetres, colour, number of legs, whether it has wings, where you found it and what time of day. Those five details, plus a clear photo, are enough to identify almost any UK household insect. Compare them against the species pages here, or send the photo and we'll tell you what it is.
Can you identify a pest from a photo?
Usually, yes. A sharp photo with something for scale — a coin or a ruler — is enough for most insects, droppings and damage. Use the form on this page; there's no charge for identification.
What are the tiny black bugs in my house?
The most common are black garden ants near food, carpet beetle adults near windows in spring, and occasionally young cockroaches in kitchens. Carpet beetles are round and patterned, ants have a narrow waist, and cockroaches are flat and fast. A photo settles it.
Which household pests are a health risk?
Rats and mice can spread leptospirosis and salmonella through urine and droppings, cockroaches carry food-poisoning bacteria, and wasp stings can cause serious allergic reactions. Bed bugs and fleas cause itchy bites but are not known to spread disease in the UK.
Is it a mouse or a rat?
Look at the droppings and the size. Mouse droppings are 3–8 mm and pointed; rat droppings are 10–14 mm and blunt. An adult mouse is under 10 cm without its tail, with big ears; a rat is 20 cm or more with small ears and a thick tail.
Free inspection · from £90
Know what it is? Let's deal with it.
Book a free inspection and we'll confirm the species, find how it's getting in and give you a written price.