Autumn Pests: What UK Pests Are Doing This Season – and How to Spot Them
Published by Jack Marsh at The Pest Company
When the leaves turn and evenings draw in, many pests don’t vanish – they relocate. Cooler, wetter weather and dwindling food supplies can push some rodents and insects indoors into our homes and businesses.
Below is a breakdown of the key autumn invaders, why they’re active now and the red flags to watch for.
Rats and Mice
Rodent numbers aren’t necessarily higher in autumn, but the problems they cause start to ramp as as temperatures drops. Shorter days and cold, wet weather drive them inside in search of stable temperatures and food. Rats and mice getting into lofts, wall cavities and other sheltered areas is a common issue this time of year.
Signs to watch for;
Droppings & odours – pellet‑shaped droppings. Grain of rice size for mice, larger for squirrels and rats.
Gnawing & nests – holes in wood or packaging, shredded insulation or chewed cables.
Noises & footprints – scratching or scampering inside walls/ceilings, dusty footprints.
Pet behaviour – pets sniffing at crevices more than usual.
Mice can slip through tiny gaps and gnaw plastic air bricks or wooden thresholds. Rats will use drains, climbing plants, vines or even jump from walls to get access.
Particularly if you are running a business, ignoring rats and mice activity is a recipe for reputational disaster.
Grey Squirrels
Non‑native Grey Squirrels are prolific breeders, and their numbers are spiralling out of control in the UK. As autumn arrives, they start house hunting, looking for lofts and roof voids to avoid the worst of the cold. Capable of leaping five times their body length, they reach roof spaces via overhanging trees. Keeping trees cut away from roof lines is top tip.
Signs to watch for:
Scratching or rolling noises in lofts or eaves.
Gnawed timbers or insulation.
Droppings or nut shells in lofts.
Cut back trees and climbing plants to limit access and consider physical proofing. DO NOT block a hole you think a squirrel is already using. A trapped in squirrel will cause lots of damage trying to escape.
Bed Bugs
Bed bugs are an all‑season menace, but autumn can see an uptick with people returning from summer holidays with hitchhiking insects in their luggage. They settle into soft furnishings and once established are hard to eliminate.
What they’re up to: Adults are small (4–5 mm), reddish‑brown, wingless and hide in seams of mattresses or furniture. They feed on blood and leave itchy bites in rows or clusters.
Signs to watch for:
Bites on skin arranged in lines or clusters.
Small dark stains on bed linen.
A sweet, sickly odour.
Visible bugs in seams or crevices.
Pro tip for hospitality businesses: Educate employees on what to look for can flag an issue early. Waiting until a customers report bites is going to be a much more difficult conversation.
Wasps
In early autumn, wasps generally are in decline, but their nests are at peak size. Queens leaving their nest to overwinter can often cause a nest that has gone unnoticed all season to suddenly be causing problems. This may require the nest to be treated, but also the loft space fumigated to clear the dispersed Queens looking for a spot to hibernate.
Cluster Flies & Other Overwintering Insects
Cluster flies are harmless but nuisance pests that hibernate in huge numbers. Adults emerge from soil in autumn and look for cool, dry places like attics, wall cavities and sunny window frames. It isn’t just flies – ladybirds and other insects congregate too.
Signs to watch for:
Swarms around south‑facing windows on warm autumn days.
Dead flies behind loft insulation or near pipes.
Piles of insects in sash or velux window frames.
Vacuuming small numbers is effective. For large infestations, professional fogging and sealing entry points where possible.
Fleas
Although flea populations spike in the summer, the problems do linger into the autumn months. Colder weather outside keeps pets spending more time indoors, plus the central heating kicking in can trigger dormant eggs and pupae to hatch.
Signs to watch for:
Pets scratching excessively or visible fleas in their fur.
Tiny black specks (“flea dirt”) on carpets or bedding.
Bites on people in the house, on lower legs and ankles.
Fleas need a two pronged attack to clear. On the pet… maintain regular vet‑approved flea treatments and wash bedding in hot water. And in the house, vacuum often and consider booking a professional pest control treatment for your home.
Remember adult fleas on the pet account for ~5% of the flea population. The eggs and pupae of the fleas also need to be addressed to fully clear the problem.
Spiders
Spiders peak in summer, but as temperatures drop they head indoors for warmth and mating. The common house spider and giant house spider are the main autumn visitors. They help control flies and are largely harmless. In low numbers they can be either left, or managed with DIY fly spray.
Occasionally their numbers can escalate, so speaking to a pest control company can help clear the decks.
Wrapping Up: Stay One Step Ahead This Autumn
As autumn settles in, remember that pests aren’t taking a seasonal break — they’re repositioning their operations indoors. Proactive pest management saves money, stress, and reputation — a win-win for homeowners and businesses alike.
At The Pest Company, we’re on call across North Yorkshire, East Yorkshire, West Yorkshire, Teesside, Cambridgeshire, and Essex — delivering fast, discreet, and professional pest-control solutions that keep your spaces pest-free year-round.
Call us today or visit www.thepestcompany.co.uk to schedule your autumn inspection.
