Noises in the loft: rats, mice, squirrels or glis glis?

How can you tell what is in your loft from the noise?

Start with the time of day. Grey squirrels are active in daylight, with peaks in the early morning and late afternoon. Rats, mice and glis glis are mostly active at night.

Then think about weight and season. Mice sound light and quick. Rats, squirrels and glis glis sound heavier. Glis glis go quiet for months over winter, while the others carry on all year.

Animal	What you hear	Time of day	Droppings	When in the year
Mice	Light, fast pattering and scratching	Night	Very small, scattered, lots of them	All year, often noticed more in autumn and winter
Rats	Heavier scratching, gnawing and scuttling	Night	Larger, in groups along their routes	All year
Grey squirrels	Scampering, scratching and heavier movement	Day, peaks early morning and late afternoon	Larger than mouse droppings	All year, they do not hibernate
Glis glis	Running, thumping and calls, often in the dead of night	Night	Similar to small rat droppings	Summer and early autumn. Silent while hibernating, about October to late May

Droppings are the most reliable clue once you can get into the loft. Our guide on rat or mouse droppings shows how to tell them apart.

What are glis glis, and why are they in local lofts?

Glis glis, also called edible or fat dormice, are small, grey, squirrel-like rodents with bushy tails. They were released at Tring Park in Hertfordshire in 1902.

In Britain they are mostly found in the Chilterns and nearby woodland, largely within 35km of Tring. They feed in trees and eat a lot of beech mast. That makes wooded parts of South Bucks a natural fit.

They are mainly nocturnal and often live in occupied houses. Typical damage in a loft is ripped insulation and gnawed beams and wiring. Young are usually born in August.

They hibernate for around seven months, typically from October to late May or June. A loft that is loud at night in summer, then goes quiet as autumn ends, fits glis glis well.

How are squirrels different?

Grey squirrels do not hibernate, so noise carries on through winter. They are larger than glis glis, with a body of about 24 to 28.5cm. Females have two litters a year, in early spring and summer.

It is illegal to release a grey squirrel into the wild. If one is caught in a live trap, it must be dispatched humanely. That is why squirrel problems are best left to a professional.

What does the law say about glis glis?

Glis glis are listed on Schedule 6 of the Wildlife and Countryside Act 1981. Trapping them is prohibited unless it is done under Natural England’s general licence CL02.

• Only a registered person, their accredited agent or a supervised assistant can use the licence.
• You must register with Natural England and wait for written confirmation before trapping.
• Traps must be checked at least once every 24 hours.
• A glis glis caught alive cannot be released. It must be killed quickly and humanely.
• Records of every animal trapped must be sent to Natural England each year.

This means you should not put down rat traps or bait in a loft until you know what is up there. Read more in glis glis in the loft: what the law allows.

What can you check yourself?

• Keep a noise log. Note the time and the kind of sound for a few days. Daytime noise points to squirrels.
• Look in daylight. Use a torch to check for droppings, chewed insulation, nesting material and gnawed cables.
• Check the wiring. If cables look chewed, ask an electrician to inspect them.
• Walk round outside. Look for overhanging branches, ivy up the walls and gaps at the eaves or roof vents.
• Do not block holes yet. Sealing a gap with animals inside can trap them in the loft. Natural England’s guidance is to proof entry points after removal.

When should you call someone?

Call us if you hear noises at night and find droppings or chewed material. We treat rats from £149 for 2 visits and mice from £139 for 2 visits, including VAT. Squirrels are priced on the phone.

We do not trap glis glis. If the signs point that way, we will tell you and explain what to look for in a registered contractor. Buckinghamshire Council’s pest service does not treat glis glis or squirrels either.

We call back within 30 minutes, Monday to Saturday, 8am to 6pm. We agree a fixed price on the phone, and visits are usually [same or next day].