top of page

Grey Squirrel
Life Cycle & Description

Description of Grey Squirrel
(Sciurus carolinensis)


The grey squirrel was deliberately introduced to Britain from North America on several occasions between 1876 and 1929. Since then it has spread throughout most of mainland England and Wales, though it is still absent from much of Scotland and from offshore islands including the Isle of Wight.

Initial spread was prevented by intense trapping and shooting, mainly by gamekeepers; however, reductions in gamekeeping intensity between 1940 and 1945 allowed the grey squirrel to establish itself more widely.
It is mainly a resident of broad-leaved and mixed broad-leafed/conifer woodland but is also found in copses and hedgerows. It is a common resident of urban areas where it lives in parks and gardens wherever there are trees. Highly adaptable the grey squirrel is able to outcompete the red squirrel whose habitat requirements are more specific and less flexible.
Grey squirrels must not be confused with the red squirrel which is protected under the Wildlife and Countryside Act 1981.


Average weight - 500g

Combined head & body length - 25 - 27cm

Tail length - 22cm

Sexually mature - 10 - 12 months

Gestation period - 45 days

Average litter size - 3 - 4

Weaning period - 10 weeks

Average lifespan - 9 years

Grey squirrels are rodents, having the characteristic incisors that grow throughout their lives, combined with an outer layer of enamel on the incisors that wears away more slowly than the inner dentine, giving the sharp cutting edge to the teeth.

Canines are absent, being replaced by the characteristic rodent diastema.
Head and body length is 25 to 26.5cm plus 22cm of tail. Weight about 500g; both sexes are similar size. The body is adapted for climbing and jumping, with sharp claws for gripping and a long bushy tail for balance.

The winter coat is grey above with a white underside; the summer coat is shorter, sleeker and brownish grey above. Red squirrels have red/brown upper parts in summer but may show
some grey on the back in winter, leading  to some confusion. Reds are smaller, lighter, have ear tufts, prominent in the winter coat, and brown on the legs and tails

Redproduction and Biology

Grey squirrels build nests (or dreys) of twigs and leaves in the forks of trees and they may also use tree hollows known as dens. Dreys and dens are used both for shelter and for breeding.
There are two breeding seasons in a year. The first litters are born in February and March after a gestation period of 45 days. The young are weaned at 10 weeks old. Second litters are born in June and July 1eaving the nest in August and September. Litters average three with a range of one to seven young.

The young are blind, deaf and naked at birth, weighing 13 to 17g. Lower incisors erupt at around 21 days and ears open at 25 to 28 days. Eyes open and upper incisors erupt at around 28 to 35 days (weight about 90g).

Young grey squirrels begin exploration and eating solids at seven weeks and are weaned at 8– 10 weeks. Between about 13 and 16 weeks the nestling coat is replaced by seasonal coat and dispersal begins soon afterwards.

The young are sometimes capable of breeding at six or seven months, but normally they will be at least 10 to 12 months before breeding.
Average adult weight is about 500g with little difference between the sexes.

Grey squirrels will eat a wide range of items from nuts, fruit buds and shoots to fungi, birds' eggs and nestlings. In suburban gardens much of their diet comes from food put out for birds or deliberately put out for the squirrels. Surplus food is often buried for retrieval at a later date
In captivity grey squirrels can live up to 20 years and they have been known to live for eight or nine years in the wild, but usually less than 1% will live for more than six years. Mean expectation of life at birth is one year but rises to two or more years for young that survive to leave the drey.


Activity begins before sunrise, especially in winter, but ends well before sunset. Main peak is four to five hours after dawn.
Home ranges are variable, but in south of England in a hardwood habitat it was 1.5ha for males and 0.5ha for females.

Males have been observed moving regular maximum distances of 310 to 480m and females,    130 to 260m.

Signs of Presence

Grey squirrels are active in the daytime and are commonly seen and identified, but they also leave a number of signs of their presence.

Dreys, mentioned above, are one of the most obvious signs. Feeding signs include pine cones from which the wings have been stripped to extract the seed leaving behind a core; nuts in which a hole has been gnawed and the nut then split open; and tooth marks left on the caps of fungi. Squirrels also strip bark, particularly from deciduous trees such as beech and sycamore; teeth marks may show on the underlying cambium. Often squirrels will take their food to a particular tree stump or fence post to eat it and the remains will be scattered on the ground.

Droppings vary in shape and colour depending on the diet, but may be spherical like those of the rabbit or more elongated, rather similar to those of rats.

Squirrel tracks are sometimes visible in mud and snow. The forefoot has four long, slender toes around a rectangular pad; the thumb is rudimentary and not seen in the track. The hind foot is elongated, with five toes – the inner fifth toe appears thumb-like. As squirrels move by hopping over the ground, the trail shows all four feet close together in a line, with the hind feet set outside and slightly in front of the forefeet.


The most serious damage in urban areas arises where grey squirrels enter the roof spaces of houses and other buildings by climbing the walls or jumping from nearby trees. Once inside they chew woodwork and ceilings, strip the insulation from electrical wiring, tear up fibreglass insulation to form a drey and sometimes drown in cold water storage tanks.

Activity inside houses not only causes concern as far as damage is concerned but also causes disturbance to sleep patterns and concerns about "attacks" on residents. Cases of grey squirrels attacking people are few, but occur. Most seem to relate to cases where the squirrels have been regularly fed and for some reason the feeding has stopped. As a consequence the squirrels’ subsequent attempts to attract attention may involve close contact with people who are in the vicinity rather than actual attacks.

In the garden they take fruit such as strawberries, apples and plums, raid the nests of small birds and dig holes in lawns to bury food. They frequently raid bird tables and nut feeders, an activity that is welcomed by some householders but causes extreme annoyance to others. If they succeed in chewing through the string holding nut feeders or coconuts these are carried off.

The major financial implications of grey squirrel activity relate to damage to forestry, woodlands and parks where they damage trees, particularly sycamore and beech, by stripping bark. This can often result in the weakening or death of leading shoots resulting in a misshapen tree.

Severe or even moderate levels of damage to trees in commercial woodlands can lead to the woodlands’ loss of commercial viability.


Prevention of Damage and Control


It is important to remember that whilst some see the grey squirrel as vermin or a problem pest, just as many do not and see the animals as a natural and welcome part of the habitat. Thus~ those attempting to undertake control will frequently find themselves in the middle of this conflict .

It must be borne in mind that many people regard grey squirrels as an attractive addition to the British fauna and will often vigorously oppose any control measures. Management of grey squirrels should be undertaken sympathetically and as far as possible without drawing undue attention to control activities.

Where squirrels are entering roof spaces the potential cost of the damage justifies the expense of proofing to exclude them physically, for example, by blocking gaps and entrance holes with tightly wedged wire netting. Proofing measures must be tailored to a specific site and the determination, ingenuity and sharp teeth of the squirrel should not be underestimated.

A metal sleeve can protect individual mature trees. This should be at least 0.75m deep and the bottom edge should be at least 1.5m from the ground. The seam should be smooth so that the squirrel cannot gain a toehold. This method is only suitable for trees that are unlikely to increase markedly in diameter, which would split the sleeve or damage the tree. Protected trees should be at least 3m away from any other tree from which the squirrel might jump. Killing squirrels will usually only provide short-term relief because the area is likely to be reinvaded 'rapidly from nearby. When damage occurs over a relatively short period (e.g. tree barking is concentrated from April to July) control carried out immediately prior to, and during, this period can be effective in preventing damage.

Spring Traps

The law requires that only "approved" spring traps are used and that they must be set in natural or artificial tunnels, to reduce the risk of killing non-target species. Natural tunnels such as holes in tree roots may be used or artificial tunnels, about 60cm long, can be made from turf, rocks, pipes, boards or fallen timber. The tunnel must be large enough to allow the arms of the trap to swing and to close, but the tunnel entrance should be reduced to 6 to 7cm wide e.g. by driving sticks into the ground, to exclude pets and other wild mammals and birds. Squirrels are inquisitive animals and will investigate such tunnels. Catches may be made throughout the year, particularly in winter and spring. Baiting is unnecessary but will improve catches.

Traps should be placed with the treadle in the middle of the tunnel and should be bedded in flush with the floor. They should be inspected daily and sprung once a week to prevent seizing due to rust.

Only traps that have been approved for the purpose may be used. Those include the Fenn MKIV and MKVI, the Sprenger No. 4 and No. 6, and others. Reference should be made to the current Spring Traps Approval Order for a complete list of approved traps. Spring traps should not be used in areas where red squirrels or polecats may be present.

Grey squirrels pose a huge threat to both domestic and commercial properties so it is advised to act quickly if you have, or suspect you have a problem with rats. Contact us today on 01282 777549 or email us at Our comprehensive site surveys at commercial premises are conducted free of charge and are carried out discreetly at a time both suitable and convenient in accordance with your working hours.

We will inspect all locations of the site in both internal and external locations, providing a full photographic digital report of our findings and survey results followed by our recommendations and next course of action to take.

Here at Atlas Environmental Services Ltd we are specialists when it comes to dealing with Grey Squirrels, our team of expert technicians have the skills and abilities to permanently eradicate and exclude these unwanted pest species from your property in Burnley or Lancashire and to prevent any further reoccurrence of ingress.

Here are some signs to look out for regarding the ingress of Grey Squirrels:

  • Sightings

  • Smell

  • Droppings

  • Hairs

  • Runs

  • Harbourage, and Nests (Dreys)

  • Damage to Property and Structures

Proofing work and preventative installations are always carried out from ourselves where required - This is always highlighted to our clients and actioned whilst on site!

We are Burnley and Lancashire's leading pest control and pest management service provider - We currently look after approximately 200 commercial sites across the North West region and visit many domestic properties on a daily and regular basis!

Our policy still remains the same - " Your Site - Remains Our Priority! "


If your having issues with Grey Squirrels or any other pest related problem within your commercial or domestic property then please feel free to contact us on 01282 777549 or email us at for an immediate response.

We are the leading service provider for rodent control and pest management services in Burnley and Lancashire!

bottom of page