Weight Average 8-9kg in spring, 11-12kg in autumn.
Origin & Distribution Badgers are widespread in Britain, being most common in the south west, rarer to the north and east; thinly distributed in Scotland. They are common throughout most of Ireland, but absent from the Isle of Mann, and most of the other islands.
General Ecology Badgers are nocturnal and rarely seen during the day. When not active, badgers usually lie up in an extensive system of underground tunnels and nesting chambers, known as a sett. Each social group usually has a main sett where the majority of the group live most of the time, but there may be odd holes scattered around the territory that are used occasionally. Badgers can live in social groups of two to 23 adults, but usually around six. These defend an area around their main sett as a territory. Territories may be as small as 30ha, but are up to 150ha or more in the Highlands. Badgers mark the boundaries of territories with their distinctive latrines. They leave their faeces in collections of shallow pits, which in aggregate are called latrines.
Diet Badgers exploit a wide variety of food items, but earthworms form the majority of the diet. They also eat fruits and berries, and other animals if times are hard, including hedgehogs.
Lifespan The maximum life expectancy is about 14 years, though very few survive so long in the wild.
Breeding Mating takes place between February and May, with implantation delayed until late winter. Only one female badger in a social group normally breeds, although sometimes two or more may do so. Litters of 2-3 cubs are born around February blind and hairless in the safety of the nest. They usually appear above ground at about 8 weeks, and weaning usually takes about 12 weeks. By late summer they are usually feeding independently but can be adversely affected by drought at this time causing starvation.
Conservation Status The Protection of Badgers Act 1992 consolidates past badger legislation and, in addition to protecting the badger itself from being killed, persecuted or trapped, makes it an offence to damage, destroy or obstruct badger setts. Where badgers pose a problem, licences can be issued to permit certain activities. Badger baiting (using dogs to fight badgers) has been outlawed since 1835. The Badgers Act 1973 afforded limited protection against badger digging, and was finally outlawed in 1981. About 80 local groups have been formed by enthusiasts wishing to protect and study badgers. Their activities include protecting badgers from diggers and baiters by reinforcing setts, helping with care and rehabilitation of injured badgers, having tunnels and badger proof fencing added to new road schemes and giving developers advice about setts.
In 1988 there were estimated to be around 42,000 social groups of badgers, and just under 200,000 adult badgers. By 1997 this had risen to just over 50,000 social groups and 310,000 adult badgers. The population is now probably stable. Mortality is high, with around one-fifth of adults dying each year. Road traffic accidents are a major cause of death. Some badgers are infected with bovine tuberculosis, particularly in the south west of England. These animals are the subject of a control campaign by Defra. There is a continuing debate about the role of badgers and cattle infecting each other with TB.
The Roe Capreolus capreolus is a small deer, reddish brown in summer, grey in winter. Distinctive black moustache stripe, white chin. Appears tail-less with white/cream rump patch which is especially conspicuous when its hairs are puffed out when the deer is alarmed. Males have short antlers, erect with no more than three points.
Size: Average height at shoulder 60-75cm. Males slightly larger. Weight: Adults 10—25kg
Origin and Distribution Roe deer are widespread throughout Scotland and much of England, and in many areas they are abundant. They are increasing their range. They are spreading southwards from their Scottish refuge, and northwards and westwards from the reintroduced populations, but are not yet but are not yet established in most of the Midlands and Kent. They have never occurred in Ireland. They are generally found in open mixed, coniferous or purely deciduous woodland, particularly at edges between woodland and open habitats. Roe deer feed throughout the 24 hours, but are most active at dusk and dawn.
General Ecology Roe deer exist solitary or in small groups, with larger groups typically feeding together during the winter. At exceptionally high densities, herds of 15 or more roe deer can be seen in open fields during the spring and summer. Males are seasonally territorial, from March to August. Young females usually establish ranges close to their mothers; juvenile males are forced to disperse further afield.
Diet Their diet is varied and includes buds and leaves of deciduous trees and shrubs, bramble, rose, ivy, herbs, conifers, ferns, heather and grasses.
Lifespan The maximum age in the wild is 16 years, but most live 7.
Breeding The breeding season, known as the rut, is from mid-July to the end of August. During this time males become very aggressive in defending their territories. They fight other males by locking antlers and pushing and twisting. Fighting may cause injuries and occasionally one or both may die. bAlthough the egg is fertilised at the time of mating it does not begin to develop inside the female’s uterus until several months later, in early January. The roe deer is the only hoofed animal in which delayed implantation occurs. Females give birth, usually to twins, but sometimes to single kids or triplets, between mid-May and mid-June. The young suckle within a few hours of birth. They are regularly left alone, lying still amongst vegetation. Their coat, dappled for about the first six weeks, helps to camouflage them. If there are twins they are left separately.
Conservation Status Roe deer have been hunted from prehistoric times. They became extinct in England, Wales and southern Scotland during the 18th century and populations were re-introduced to southern England (Dorset) and East Anglia in the 19th century. As they have become more abundant, they have been treated as “vermin” because of damage to forestry, agriculture and horticulture, and consequently numbers are controlled. Roe deer may now number as many as 500,000, and are increasing. Since the 1970s there has been an increased interest in exploitation of roe as a game species and for meat. As a result they are now covered by various Acts of Parliament which impose close seasons (when deer may not be hunted), firearms restrictions and controls on poaching.
The bottlenose dolphin (Tursiops truncatus) is a large stocky dolphin around 2.5 – 3.0 metres in length and weighing 200-275 kg. They have a large sickle shaped fin and they can leap right out of the water.
The bottlenose dolphins are often seen near the coast – in bays and around harbours, although herds can also be seen far offshore, often accompanying much larger pilot whales. When individuals – usually males – become separated from the social group, they may seek contact with humans.
Diet Although the bottlenose dolphin takes a wide variety of schooling fish including herring, mackerel, cod, bass, salmon, and sea trout, in many parts of its range around the world coastal populations are thought to favour bottom-living fish such as mullet, moray eels and flounder.
Reproduction A single calf about a metre in length is born during the summer months, usually between March and September, with the mating having taken place twelve months before. The calf is nursed immediately by the mother, who may be assisted by other females.
If necessary, they will help the calf up to the surface for its first breath and the mother may also be assisted if she is weak. The calf is suckled for around 18-20 months, so its mother usually cannot breed again for two or three years and sometimes six years can elapse between calves. It is a long time before a young bottlenose dolphin reaches sexual maturity – between 8 and 15 years for males and 5-13 for females. However, both sexes can live for more than 25 years, and females have been known to live over 50 years, so she may give birth to several young in her lifetime.
Threats Bottlenose dolphins face a number of modern threats. Favouring sheltered bays and estuaries with an abundance of fish, they are vulnerable to inputs of pollutants; vessel collisions and sound disturbance from large numbers of pleasure craft; and accidental capture in fishing nets, particularly coastal set nets for salmon.
The common dolphin (Delphinus delphis) is also known as the short-beaked common dolphin and is one of the smallest of the dolphins, measuring 2.1 – 2.4 metres in length and weighing 75 – 85 kg. The body is long and slender, as is the beak, and the dorsal fin is tall and pointed. The species is often confused with the striped dolphin Stenella coeruleoalba, but the common dolphin’s haracteristic hourglass or criss-cross pattern on its flanks is a good distinguishing feature. This patch is tan or yellowish in colour before the dorsal fin, and pale grey behind. Common dolphins are very agile and active.
They commonly bow-ride, often accompanying boats for many miles, and are capable of swimming at great speed, as well as engaging in energetic aerial acrobatics.
Diet Mainly opportunistic feeders, the common dolphin diet is very varied, consisting chiefly of small schooling fish such as cod, hake, mackerel, sardine, pilchard, horse mackerel, scad, sprat, sand eel, herring, whiting and blue whiting, as well as squid – the type of food taken depends on local availability. Groups of dolphins often use co-operative feeding techniques to herd schools of fish, panicking the fish through frenzied activity and taking them in the confusion.
Social Behaviour The common dolphin is a gregarious animal, often found in large, active schools. In British waters, most herds consist of less than 30 individuals, and animals often occur solitarily or in pairs, although occasional schools of more than one hundred dolphins can be seen. School size increases in mid-summer and midwinter, possibly linked to the dolphins following prey moving inshore. They are highly vocal, emitting high-pitched squeals that can often be heard easily above the surface of the water.
Common dolphins develop strong social bonds, particularly between mother and young, and males and females; if one animal is captured or injured, the other will remain in attendance, and frequently shows much distress at its companion’s plight, squeaking and squealing.
Reproduction Common dolphins appear to have two calving peaks – spring and autumn – with a gestation period of 10 – 11 months. Other females may assist the mother with the birth and also take part in ‘baby-sitting’ while the mother feeds. Calves are 80 – 90 cm long at birth. They are weaned at the age of around 19 months, and the mother has a resting period of about four months before her next pregnancy so that calving intervals are generally 2-3 years or more. Males become sexually mature at 5-7 years of age, and females at around six years. Common dolphins can live to 30-35 years.
Status and Distribution In the British Isles, they are common in the western approaches to the Channel and the southern Irish Sea (particularly around the celtic Deep) and around the Inner Hebrides north to Skye. In recent years, the species has occurred further north and east in shelf seas – around Shetland and Orkney, and in the northern North Sea, reflecting changes in the strength of the Gulf Stream. It is generally rare to see them in the southern North Sea and eastern portion of the Channel.
Threats The major threat facing common dolphins in British waters in recent years appears to be entanglement in trawl and purse seine nets in the Celtic Sea and Bay of Biscay. This has resulted in large numbers dying and subsequently being washed ashore, particularly in the southwest of Britain, due to the fact that they often prey on the same species as the fisheries, thus becoming a prime target for accidental capture. Although there is no evidence of serious organochlorine contamination in eastern North Atlantic common dolphins, specimens from the Atlantic coast of France have been found with high levels of methyl mercury (max 631 Cg/g dry weight in the liver), with levels of total mercury increasing with age.
https://letsgowild.co.uk/wp-content/uploads/2017/10/commondolphin.jpg233350Kathyhttps://letsgowild.co.uk/wp-content/uploads/lgw-header-img.pngKathy2017-10-28 09:56:142018-09-28 15:47:54Dolphin - Common
Habitat Deciduous woodland, Mixed woodland and Coniferous woodland.
Description Orange/yellow fur; our only small mammal with a very distinctive thick furry tail. Large eyes and ears (because it is nocturnal); Paws turn sideways (for climbing).
Size 60-90mm, tail 57-68mm
Weight 10-15g in juveniles; 15-26g in adults, up to 43g before hibernation.
Origin and Distribution Dormice occur mainly in southern counties, especially in Devon, Somerset, Sussex and Kent. There are few recorded localities north of the Midlands, though they are present in parts of the Lake District and in scattered Welsh localities. The dormouse is found in deciduous woodland and overgrown hedgerows.
General Ecology The dormouse is a strictly nocturnal species, found in deciduous woodland and overgrown hedgerows. It spends most of its time climbing among tree branches in search of food, and rarely comes to the ground. During the day it sleeps in a nest, often in a hollow tree branch or a deserted bird nest or nest box. Dormice are able to lower their body temperature and become torpid, so saving energy, if food is short or weather prevents them foraging. During the winter they hibernate and are not normally active again until April or May. Thus dormice may spend three-quarters of their year ‘asleep’.
Dormice live at low population densities (one tenth as abundant as bank voles and wood mice in the same habitats).
Diet Dormice feed on flowers, pollen, fruits, insects and nuts.
Lifespan Up to five years.
Breeding They can raise one or occasionally two litters a year, each usually of about four young. The new-born dormice remain with their mother for 6-8 weeks before becoming independent. The breeding season and success depends very much on the weather.
Conservation Status Dormice are strictly protected by law and may not be intentionally killed, injured or disturbed in their nests, collected, trapped or sold except under licence. Their principal requirement is for a diverse habitat featuring several different trees and shrubs to provide food throughout the summer. Coppice management of wood-lands can create such conditions; but cleared areas and wide rides may interfere with the movements of dormice, because the animals live almost exclusively in the trees. Surveys show dormice have declined in Britain this century. Loss and fragmentation of ancient woodlands, climatic difficulties and suspension of coppicing are all probably connected with this. Nest boxes, put up with the entrance facing a tree trunk, are attractive to dormice and help survival and breeding success.
Re-introductions of dormice are often suggested, but these require suitable (large) areas of woodland habitat and long periods of supplementary feeding. Breeding dormice in captivity is difficult and wild-caught animals are unlikely to be available in sufficient numbers. If fewer than 20 animals are released there is a high risk of failure. However, they have been success-fully reintroduced since 1992 to several counties (including Cheshire, Cambridgeshire, Derbyshire).
Many thanks to the Mammal Society for sharing the information, for more details on the Society please visit their website below:
Field voles (Microtus agrestis) have grey-brown fur above, creamy-grey fur below, has a tail much shorter than the bank vole, and fur is shaggier, covering the ears. Rounded snout, less prominent eyes than mice and ears are furry.
Origin and Distribution Field voles are found throughout mainland Britain and remains date back to before the end of the last glaci- ation, 11000 years ago. They are absent from a number of islands including Shetland, the Isle of Man, Isles of Scilly, Lundy and Ireland and replaced by larger Orkney and Guernsey voles on the respective islands. The field vole occurs typically in ungrazed grassland or in the early stages of forestry plantations but may also live in woodland, hedgerows, dunes, scree or moorland, wherever grass is available. Shredded grass leaves are used to make their nests which are about 10cm in diameter and may be built at the base of grass tussocks, in underground burrows or even under sheets of corrugated iron.
General Ecology Like all small mammals, the field vole is host to a number of parasites, carrying fleas and possibly ticks and worms. It must be particularly careful to avoid predators which include kestrels and owls, together with foxes, weasels and stoats. The number of young reared by kestrels and owls has been shown to increase when vole numbers increase. In extensive grasslands, field vole populations may fluctuate on a 4-year cycle with numbers increasing tenfold between the lows and highs.
Diet Grass is the field voles’ major food source, with bents, fescues and hair grasses being preferred.
Lifespan The average life span of a field vole is up to 1 year.
Breeding The breeding season begins in March/April and ends between October and December. Four or five young are normally found in each litter and females will give birth to five or six litters each year. Although this gives rise to large numbers, population turnover is rapid. Voles do not hibernate but moult to cope with the inevitable change in temperature with the seasons. Moulting provides a dense layer of fur for winter and a “lighter” coat in spring.
Conservation Status Field voles are very widespread and are currently thought to be the most common British mammal; a recent population estimate put the number of field voles in Britain at 75,000,000. Although the field vole is numerous, it is still important to consider conservation methods and maintain biodiversity within habitats, not least because field voles are so important to owls and other predators. Leaving wide field margins beside hedgerows provides cover and food which will encourage and maintain populations. Long grass on roadside verges is also important. A varied woodland area will encourage small mammals and groups of branches should be left when clearing patches of ground.
The grey seals (Halichoerus grypus) are very large animals, males can grow up to 3 metres long and weigh 300kg! The Grey Seal spends most of its time out at sea, where it feeds on fish. Mainly greyish in colour, with darker blotches and spots. The Grey Seal is more often found on rocky shores, although large colony of Grey Seals breeds in the sand dunes at Donna Nook on the Lincolnshire coast: the fluffy white pups can be seen between October and December.
How to Identify Can be told from Common Seal by its larger size and by the longer head with a sloping ‘roman nose’ profile.
Distribution Found around the coasts of Wales, Scotland, Northern Ireland and parts of eastern England and south west England.
Credit A recommended reference book for further information is the ‘Great British Marine Animals’ by Paul Naylor. (www.marinephoto.co.uk)
The harbour porpoise (Phocoena phocoena) is the smallest species of cetacean found in European waters, measuring around 1.3 – 1.5 metres in length and weighing 50 – 60 kg. It is often confused with dolphins, particularly the bottlenose dolphin. The porpoise is rotund in shape, with a small triangular dorsal fin which shows briefly above the surface – usually little of the animal is seen, as it rarely leaves the water entirely. It has a small rounded head with no distinct beak.
Harbour porpoises do not usually approach boats nor bow ride, although they can be observed at close quarters from a dinghy or small inflatable boat, and in late summer, may actually approach vessels.
Diet The harbour porpoise eats a varied diet of fish, cephalopods and crustaceans, related to local availability of food; in European waters, herring, mackerel, sand-eel, gobies and a wide range of gadoid fish such as cod, saithe, pollack, and whiting are all known to form prey of porpoises. The apparent flexibility in diet helps the porpoise to avoid being adversely affected by local human over-exploitation of any single fish species. However, intense exploitation of fish stocks overall can put great pressure on marine mammals like porpoises that are dependent on them for food.
Social Behaviour Harbour porpoises generally live in groups of two or three animals, or singly, but occasionally forming groups of 10 – 20 animals. Larger aggregations of up to several hundred porpoises have also been seen seasonally (Feb-March & Aug-Oct), either associated with food concentrations or long-distance movement.
The basic social unit appears to be the mother and calf, which may sometimes be accompanied by a yearling. Segregation by age and sex may also occur in larger groups. DNA studies indicate that females can form genetically distinct groups, while males are more likely to move away. During late summer, porpoises are more social, and sexual activity can be observed. In calm seas, animals frequently lie in a resting state just below the surface.
Rerproduction The main mating season is summer, and birth takes place 10-11 months later (usually between May and August with a peak in June). Calves are suckled for between four and eight months, and the mother usually reproduces every 1-2 years. Porpoises take three to four years to reach sexual maturity and have a relatively short life span usually of no more than 15 years, although animals have been recorded up to 24 years of age.
Status and Distribution
As the name suggests, the harbour porpoise is commonly seen in coastal areas, although it ranges over much of the European continental shelf. It is the commonest and most widely distributed of all cetacean species in northern Europe, favouring comparatively shallow, cold waters.
There are seasonal concentrations of harbour porpoises off south-west and western Ireland, west Wales, the west coast of Scotland, Northern Isles, and eastern Scotland – porpoises may be permanent residents in these areas, with the greatest numbers usually between July and October. Like the bottlenose dolphin, the species was once a regular visitor to the south coast of England and the southern part of the North Sea during the summer months, but then became a rare sight in these areas.
Genetic studies have indicated that around the British Isles, there are separate populations in the Irish Sea and off the Welsh coast; in the northern North Sea; eastern (Denmark) and western (UK) North Sea; and southern North Sea (Netherlands). Further research may reveal other genetically distinct populations.
Threats Despite the fact that the harbour porpoise is probably the commonest small cetacean in UK waters, it is thought to have undergone substantial declines in numbers over the last fifty years, with the species becoming rare in the southernmost North Sea and Channel. Although reasons for this status change are not known for certain, pollution, disturbance, lack of food and entanglement in fishing nets have all been implicated.
Hedgehogs are our only spiny mammals. They have a short inconspicuous tail, small ears and relatively long legs, which are all covered with dense, sharp, brown spines. When they are alarmed, they protect themselves by rolling up into a defensive ball and effectively fend off any lurking predators.
They are active at night or sometimes after heavy rainfall, and rely heavily on their keen sense of smell to find food, to recognise other hedgehogs or to sense danger. Hedgehogs travel large distances every night and stop to feed at various places on the way. They are often regarded as slow animals but, if they want to, they can move up to 40m in a minute, which is no mean feat considering their size!
During cold winters, when food becomes scarce, hedgehogs conserve energy by making a nest in a sheltered spot and then becoming inactive by dropping their heart beat from 190 to 20 beats per minute. Their body temperature drops from 37C to near freezing. This is called ‘hibernation’ and the amount of time they remain like this really depends on the weather.
Breeding The hedgehog breeding season generally lasts from April until September. Females are usually pregnant for about four and a half weeks and then give birth to up to seven pink, sightless young in a nest made of grass and leaves. Soon after birth, the young grow short white spines, which they lose within a few weeks when the brown spines grow through. They feed on the mother’s milk and become independent at two months old.
Diet Worms, beetles, caterpillars, slugs and snails.
Habitat Hedgehogs need overgrown hedgerows and woodland edges to nest and rough pasture to find food. They tend not to live in wet areas or large pine forests.
Predators and Threats Badgers and foxes occasionally eat hedgehogs. Many are killed on roads or killed as a result of eating poisonous slug pellets used in gardens.
Status and Distribution Hedgehogs are found throughout the British Isles, including urban areas, but not on some of the Scottish Islands. They are common and widely distributed but are in severe decline, both in the countryside and in our towns and cities.
Harvest mice (Micromys minutus) are Britain’s smallest rodent, weighing around 4-6g as adults, with a head and body length of 50-70mm. They have golden fur and a pale underside with incredible semi-prehensile tails, meaning that their tail is adapted to be able to grasp or hold on to objects. They are very active climbers and so this is very handy for holding on to the stems of plants.
They prefer tall, dense grassy vegetation and build nests of woven grass above ground level in the stalk zone of the vegetation. They inhabit central Yorkshire southwards, with a higher density towards the South East, although isolated populations may be found outside of this range, possibly from the release of captive individuals.
Harvest mice have many predators including weasels, stoats, foxes, cats, owls, hawks, crows and even pheasants. They live on a diet of seeds, berries and insects and may feed on moss, fungi or roots. They live on average for around 18 months.
If you spot any harvest mice or their field signs (such as their round nests) please do report your sighting on The Mammal Society website so that we can include it in our National Mammal Atlas Project (NMAP) which is working to paint a fuller picture of the whereabouts and numbers of our British mammals.
To find out more about mammals or how you can help them please visit The Mammal Society website below:
Origin & Distribution Moles are found throughout Britain but not in Ireland. They are present in most habitats where the soil is deep enough to allow tunnelling but are uncommon in coniferous forests, on moorlands and in sand dunes, probably because their prey is scarce.
General Ecology Moles spend almost all their lives underground in a system of permanent and semi-permanent tunnels. Surface tunnels are usually short-lived and occur in newly cultivated fields, in areas of light sandy soil and in very shallow soils, where prey is concentrated just below the surface. More usual is a system of permanent deep burrows which form a complex network hundreds of metres long at varying depths in the soil. The deepest tunnels are used most in times of drought and low temperatures. Permanent tunnels are used repeatedly for feeding over long periods of time, sometimes by several generations of moles.
Diet Earthworms are the most important component of the mole’s diet; an 80g mole needs 50g of earthworms per day. Moles also eat many insect larvae particularly in the summer, though earthworms dominate the winter diet. Moles sometimes collect and store their food (earthworms) alive in special chambers. The stored worms are immobilised by a bite to the head segment, 470 worms have been recorded in one chamber.
Lifespan Most moles don’t live beyond 3 years but can live up to 6 years. Their main predators are tawny owls and buzzards; stoats, cats and dogs, also vehicles kill some. Humans also kill many as pests of agriculture.
Breeding Males and females are solitary for most of the year, occupying exclusive territories. With the start of the breeding season males enlarge their territories, tunnelling over large areas in search of females. Within the tunnel system moles construct one or more spherical nest chambers, each lined with a ball of dry plant material. Nests are used for sleeping and for raising young. A litter of 3 or 4 naked babies is born in the spring. Fur starts to grow at 14 days, eyes open at 22 days and they are weaned at 4-5 weeks. The young start to leave the nest at 33 days and disperse from their mother’s range at 5-6 weeks. Dispersal takes place above ground and is a time of great danger. Moles are sexually mature in the spring following birth.
Conservation Status Moles have no legal protection in the U.K. and are frequently regarded as pests by farmers, horticulturists and green-keepers. Surface tunnelling in newly planted fields may disturb plant roots so much that they will wilt and die. Mole hills cause damage to farm machinery and also cause contamination of grass used to make silage. At the beginning of the century moles were trapped in large numbers for their pelts but today they are killed as pests. This is done by trapping, which can be cruel.
Moles used to be commonly poisoned using strychnine. Death by strychnine poisoning is slow and agonizing, and strychnine is highly dangerous to other wildlife, domestic animals and humans. For these reasons it is now illegal to use strychnine for poisoning moles or any other animals. Moles can be beneficial to man, preying on many harmful insect larvae such as cockchafers and carrot fly, while tunnels help drain and aerate heavy soils.
Thank you to the Mammal Society for sharing this wonderful information.
Wood mouse (Apodemus sylvaticus) – A small rodent with sandy brown fur (darker towards the spine) with a white/grey underside, protruding eyes, large ears, long tail. Juveniles are greyer overall, still with larger ears, hind feet and tails than house mice.
Origin and Distribution Found throughout the British Isles, even on the smaller islands, the wood mouse is our most common and widespread wild rodent. It is an inhabitant mainly of woodland and fields but is highly adaptable and is found in most habitats if not too wet. It is rarely recorded on higher exposed ground with little cover. Wood mice are essentially nocturnal but some individuals may venture out in daylight.
General Ecology Most wood mice live in underground burrows. The burrows are fairly complicated and may include nest chambers and food stores. Burrows probably survive from one generation to the next and will be enlarged or modified as required. Nests are commonly made of leaves, moss and grass. They are usually built below ground under the roots of shrubs or trees but occasionally are found in holes in trees, buildings and bird or dormouse nest boxes. Additional nesting material is used in autumn and winter; often the mouse blocks the entrance to the burrow with leaves, twigs or stones.
Individuals will nest communally in the winter but in the spring females usually take up their own home ranges and nest singly. However, home ranges shared by two females have been observed. Breeding males range over larger areas occupied by a number of females.
Their predators include foxes, weasels, owls and domestic cats. Wood mice are important prey for tawny owls; when numbers of woodland rodents are low, owls may fail to breed.
Diet Seeds, green plants, fruits and animal foods. In a mixed deciduous woodland: acorns, ash and sycamore seeds for most of the winter, buds in early spring, caterpillars, worms and centipedes in early summer and blackberries and fungi in the autumn. Food is cached in underground burrows. Food remains are found in disused bird nests, on tree stumps and in sheltered feeding places between the roots of trees or under ledges. They tend to leave the flesh of fruit and eat only the pips.
Lifespan Few adults survive from one summer to the next.
Breeding Litters of 4-7 young are born in successive pregnancies from March to October but autumn litters are small. The babies are born blind (eyes closed) and hairless. They are weaned at 18-22 days of age when their weight is about 6-8 grams. Growth in the summer is rapid and females can become pregnant when they have reached a weight of 12 grams. Breeding may continue over the winter if a good food supply, such as a heavy acorn crop, is available.
Conservation Status Wood mice have no legal protection and conservation does not seem necessary as recolonisation after mortality is often rapid. Wood mice can be beneficial to man by preying on harmful insects, and many trees and shrubs germinate from forgotten wood mouse food stores.
Studies of woodland seed crops and population numbers organised by the Mammal Society show that the seed crop size strongly influences wood mouse numbers in the same autumn and in the following summer (more food leads to higher numbers and better survival). Numbers are probably synchronised: highs and lows tend to coincide in different parts of Britain, possible because tree seed crops are synchronised.
Otters have brown fur and often pale on the underside. They have long slender bodies; small ears on a broad head a long thick tail with webbed feet. They swim very low in the water with their head and back barely showing.
Size About 60-80cm; tail about 32-56cm
Weight Average 8.2 kg for males; 6.0 kg for females.
Origin and Distribution The otter is a secretive semi-aquatic species which was once widespread in Britain. By the 1970s, otters were restricted mainly to Scotland, especially the islands and the north-west coast, western Wales, parts of East Anglia and the West Country (though they remained common and widespread also in Ireland). This decline was caused by organo-chlorine pesticides. Since these were withdrawn from use, otters have been spreading back into many areas, especially in northern and western England.
General Ecology Otters can travel over large areas. Some are known to use 20 kilometres or more of river habitat. Otters deposit faeces (known as spraints, with a characteristic sweet musky odour) in prominent places around their ranges. These serve to mark an otter’s range, defending its territory but also helping neighbours keep in social contact with one another. Females with cubs reduce sprainting to avoid detection.
Diet Fish, especially eels and salmonids are eaten, and crayfish at certain times of the year. Coastal otters in Shetland eat bottom-living species such as eelpout, rockling and butterfish. Otters occasionally take water birds such as coots, moorhens and ducks. In the spring, frogs are an important food item.
Lifespan Up to 10, though few survive more than five years.
Breeding In England and Wales otter cubs, usually in litters of two or three, can be born at any time of the year. In Shetland and North-west Scotland most births occur in summer. Cubs are normally born in dens, called holts, which can be in a tree root system, a hole in a bank or under a pile of rocks. About 10 weeks elapse before cubs venture out of the holt with their mother, who raises the cubs without help from the male.
Conservation Status Otters are strictly protected by the Wildlife and Countryside Act (1981) and cannot be killed, kept or sold (even stuffed specimens) except under licence. In the late 1950s and early 1960s otters underwent a sudden and catastrophic decline throughout much of Britain and Europe. The cause was probably the combined effects of pollution and habitat destruction, particularly the drainage of wet areas. Otters require clean rivers with an abundant, varied supply of food and plenty of bank-side vegetation offering secluded sites for their holts. Riversides often lack the appropriate cover for otters to lie up during the day. Such areas can be made more attractive to otters by establishing “otter havens”, where river banks are planted-up and kept free from human disturbance. Marshes may also be very important habitat, for raising young and as a source of frogs.
While otters completely disappeared from the rivers of most of central and southern England in just 50 years, their future now looks much brighter. There is evidence that in certain parts of the UK the otter is extending its range and may be increasing locally. Otter populations in England are very fragmented and the animals breed only slowly. Attempts have been made to reintroduce otters to their former haunts, by reintroducing captive bred and rehabilitated animals, with some attempts proving very successful.
Origin and Distribution Pine martens are found in the Scottish Highlands and Grampians, with isolated populations in southern Scotland. In England and North Wales pine martens seem to be on the verge of extinction. They are widespread and relatively common in Ireland. Although they occur in a wide range of habitats, pine martens prefer well-wooded areas with plenty of cover.
General Ecology Marten dens are commonly found in hollow trees or the fallen root masses of Scots pines, an association that probably earned pine martens their name; cairns and cliffs covered with scrub are frequently used as alternative den sites. Martens have territories that vary in size according to habitat and food availability; for males these are about 10-25 square kilometres and for females about 5-15 square kilometres. They mark their territories with faeces (known as scats) deposited in places where they are conspicuous to other martens; they are frequently left along forestry trails.
Diet Pine martens are generalist predators, feeding on small rodents, birds, beetles, carrion, eggs and fungi. In autumn, berries are a staple.
Lifespan Maximum life expectancy is 8 years.
Breeding Young martens are born blind and hairless, in litters of 1-5, in early spring and stay with their mothers for about six weeks. Their eyes open at the end of May and by mid-June they begin to emerge from their den. Male martens play no direct part in rearing the young.
Conservation Status Martens and their dens are fully protected by the Wildlife and Countryside Act (1981); martens must not be trapped, sold or disturbed except under licence from Scottish Natural Heritage, the Countryside Council for Wales or Natural England. Despite this legal protection, poisoned baits and traps, often set for hooded crows and foxes, still probably account for many marten deaths each year. Others are also shot at hen houses, and some are killed when mistaken for mink.
Until the 19th Century, pine martens were found throughout much of mainland Britain, the Isle of Wight and some of the Scottish islands. Habitat fragmentation, persecution by gamekeepers and martens being killed for their fur, drastically reduced this distribution. By 1926, the main pine marten population in Britain was restricted to a small area of north-west Scotland, with small numbers in N Wales and the Lake District. They have now increased their range in Scotland, and now occur throughout the Highlands, N of the Central Belt but remains one of the rarest native mammals in Great Britain, with a total population of around 3-4,000, but Ireland probably also has as many.
Polecats (Mustela putorius) – Blackish guard hairs and yellow under fur on the body, giving ‘black and tan’ appearance; banded “bandit” face: pale muzzle, ear tips and ‘eyebrows’, with a broad dark band around the eyes; darker legs and belly, short fluffy tail; is the size of a ferret
Weight Males weigh around 0.8-1.9kg, females 0.5-1.1kg.
Origin and Distribution Polecats are found throughout Wales where valleys and farms are favoured, the midlands and parts of central southern England, and are spreading steadily from these areas. There are isolated populations in Cumbria and Caithness, which probably result from unofficial releases. Once, polecats were widespread throughout Great Britain, but were nearly exterminated by 1915. They never occurred in Ireland, or on the outer islands. Although they occur in a wide range of habitats, polecats prefer lowland areas. In England, farmland with hedgerows and small woods is preferred.
General Ecology Polecat dens are commonly found in rabbit burrows, especially in summer, but they frequently move into farmyards in winter, when they may den in hay bales, under sheds and in rubbish tips. Polecats have territories that vary in size according to habitat and food availability. For males they have been measured at 16-500 ha, and for females about 25-375 ha, using radio-tracking. Territoriality seems weaker in polecats than other mustelids, perhaps because they move around more to exploit seasonally abundant food sources. There are often piles of scats near den sites, but little evidence that scats are left around the territory to defend its borders. Polecats have scent glands either side of the anus, and they produce a pungent, repellent scent.
Diet In summer, rabbits are a major food, and polecats are slender enough to hunt them within their burrows. In winter, common rats become a favoured food, and sites with good rat populations become usual habitats. Birds may be taken and frogs may be important in spring, when gathered to spawn.
Lifespan Up to 14 years in captivity, probably five years in the wild.
Breeding Polecats have one litter a year, with 5-10 young born blind and hairless in late May-early June. They begin to take meat from 3 weeks, and stay with their mothers for 2-3 months. They reach adult size by autumn, and breed at one year old. Pregnancy is direct (no delayed implantation) lasting 40-43 days. Male polecats play no direct part in rearing the young.
Conservation Status In addition to its protection under the Wildlife and Countryside Act 1981, the polecat has recently (2007) been added to the list of UK BAP mammals, protected as species of principal importance for the conservation of biological diversity in England under Section 74 of the Countryside and Rights of Way (CRoW) Act 2000. Until the 19th Century, polecats were found throughout much of mainland Britain and the Isle of Wight. Habitat fragmentation, persecution by gamekeepers and being killed for their fur drastically reduced this distribution. The polecat population was reduced to about 5,000, but is now more than 46,000. Road accidents are a major threat as they tend to be attracted to other road kill items for food.
The Red squirrel’s (Sciurus vulgaris) fur colour varies from bright ginger through to red and dark brown or black tinged with grey in winter; larger ear tufts in mid-winter which disappear by the summer; bushy tail which bleaches white by late summer in some individuals.
Size: 180-240mm, tail about 175mm. Weight: Juveniles: 100-150g; Adults up to 350g.
Habitat Upland & moorland, Coniferous woodland
Origin and Distribution Red squirrels spend about three-quarters of their active time above ground in trees and shrubs, and are at home in both conifer forests and broadleaved woodland. The distribution of red squirrels has declined drastically in the last 60 years and they are now extinct in southern England except for a few on the Isle of Wight and two small islands in Poole Harbour. Elsewhere in central Britain they are confined to rather isolated populations in Wales (notably Anglesey) and around Formby in Merseyside. Red squirrels are still widespread in the North of England and Scotland, and in Ireland, but even here their range is contracting.
General Ecology Red Squirrels are active during the daytime, though in summer it may rest for an hour or two around mid-day. Squirrel nests, or dreys, are constructed of twigs in a tree fork, above a whorl of branches close to the stem of a conifer, or, less visibly, in a hole in a tree. They are lined with soft hair, moss and dried grass. Several squirrels may share the same drey, or use the same drey on different days.
Diet Their min foods are tree seeds, especially hazel nuts and seeds from conifer cones. They also eat tree flowers and shoots, mushrooms and fungi from under tree bark. They often suffer periods of food shortage, especially during July.
Lifespan They survive for up to six years in the wild.
Breeding Breeding can begin in mid-winter and continue through the summer, depending on the weather and how much food is available. Mating chases occur where several males follow a female who is ready to mate. During chases squirrels make spectacular leaps through the tree canopy and spiral up and down tree trunks. Females have one or two litters a year, usually of about 2-3 young. Juveniles are weaned at around 10 weeks, but do not breed until they are one year old.
Conservation Status Red squirrels are protected by law, and may not be intentionally trapped, killed or kept, or have their dreys disturbed except under licence from Natural England (NE), the Countryside Council for Wales (CCW) or Scottish Natural Heritage (SNH). Red squirrels are considered vulnerable in Britain. However, occasionally high densities in some Scottish forests can lead to economic damage to trees. In such cases, government agencies will assess whether to issue a licence to remove some of them.
Despite historically high numbers, the introduction of grey squirrels during the early 20th century greatly contributed to their decline through disease transfer and indirect competition (better foraging efficiencies). The only certain way to sustain red squirrel populations is through the exclusion of grey squirrels. This can be achieved through the creation of habitats favourable for only red squirrels, selective feeders or lethal exclusion. To improve the success of reintroductions further research is required.
Common shrews are one of Britain’s most abundant small mammals. They are recognisable from their long, narrow, twitching snout, silky brown fur and grey underside. They are very hard mammals to spot as they spend much of their life either beneath the leaf litter, where they use old mouse runs to get around, or in the soil, where they dig their own burrows. Occasionally, a high-pitched squeak can be heard in the grass, which is a good sign that shrews are about!
They are most active at night, particularly at dusk and dawn and are solitary animals that can be very aggressive towards each other. Their eyesight is poor and so they use their acute sense of smell to detect their food. Their long snout and whiskers are constantly probing and sniffing the soil to find food and they can locate prey, which is up to 12cm underground.
Breeding Common shrews mate between April & September and after a pregnancy of 22-24 days, the females give birth to six or seven blind, hairless young. The young grow rapidly and become independent within three weeks but 50% of young shrews die in the first two months. Females can have two to four litters per year depending on the weather and the availability of food.
Diet Worms, spiders, slugs, insect larvae, beetles and woodlice.
Habitat Woodland, thick grass and hedgerows, particularly road verges and other grassy banks. They make nests of dried grass and leaves under logs and grass tussocks or in the burrows of other species.
Predators and Threats Mostly owls but also stoats, weasels and foxes. Domestic cats frequently kill shrews but do not eat them, because of their unpleasant taste.
Status and Distribution Common shrews are very common and widely distributed throughout mainland Britain. They are however absent from Ireland, the Isle of Man, the Northern Isles and the Outer Hebrides.
The Pygmy Shrew is a very small mammal with a markedly pointed snout. As in the common shrew the fur is greyish brown (dirty white ventrally) but the pygmy shrew is smaller and has a proportionately longer and thicker tail.
Size 40-60 mm; tail 32-46mm
Weight 2.4-6.1g. Weight may decrease up to 28% in winter.
Diet They feed mainly on insects, arachnids and woodlice, requiring regular meals and eating up to 125% of their body weight in food daily. Unlike common shrews, they rarely eat earthworms.
Lifespan Peak mortality is at 2-4 months and the maximum lifespan is around 13 months.
Origin and Distribution Widespread throughout the mainland of Britain and Ireland, in most terrestrial habitats which offer sufficient ground cover. They are also found on the Isle of Man and Outer Hebrides, where common shrews are absent. Pygmy shrews are active day and night, largely above ground. They make and use “surface tunnels” in vegetation and will frequent burrows dug by other animals. They seem to be relatively more common on moorland than are common shrews.
Behaviour As in all shrews, senses of smell, hearing and touch are well-developed. Pygmy shrews are solitary and aggressive towards conspecifics. Home ranges vary from around 500-2000 square metres, depending on habitat, with maximum densities of around 12 per hectare. Strict territoriality is only abandoned during the breeding season.
Breeding Pygmy shrews overwinter as immatures and breed between April and October, producing two or three litters of 5-7 young. Their main predators are owls and other avian predators, particularly those which hunt on moorland.
Conservation Status Shrews are protected under the 1981 Wildlife & Countryside Act. As with all shrews, they may be trapped only under licence. In any trapping study on small mammals, care is necessary to avoid killing shrews, which are extremely susceptible to death by starvation due to their small size and correspondingly high metabolic rate. Traps should be provided with suitable food (e.g. mealworms, meat) and/or visited at least every 2 hours. The main habitat requirements are vegetation cover and invertebrate food.
Water shrews are the largest of the British shrews. These frantic little mammals are very well adapted to an aquatic lifestyle. They have a dark black-brown coat of short fur that is paler underneath and which is waterproof and stays dry, even while swimming. Unlike the other shrews found in Britain, they have hidden ears, only visible as white tufts, which they can close when they are in the water. They have a stiff fringe of hair beneath their tail, which they use as a rudder when swimming and they can dive to depths of over 70cm.
Water shrews are mostly active at night, particularly just before dawn. They need to eat 50% of their body weight every day to stay alive and can travel up to 160 metres along the water’s edge to find food and shelter. They do not hibernate but remain active throughout the winter when their dense fur protects them from the cold and wet.
Breeding Pregnancy lasts roughly 20 days and 3-5 young are born per litter between April and September, with a peak of activity in May and June. Females have between one and three litters in a season. The juveniles usually leave the nest at six weeks old.
Diet Mainly freshwater crustaceans such as shrimps, caddis-fly larvae and small snails, but also small fish and frogs, earthworms, snails and beetles.
Habitat Usually unpolluted, fast flowing water, in reed-beds, watercress beds, fens and along riverbanks. They dig extensive networks of small burrows and chambers, about 2cm wide, in the banks of streams, which they line with grass and leaves.
Predators and Threats Occasionally owls, kestrels, foxes, large fish and cats but most water shrews die from exhaustion after the breeding season.
Status and Distribution Water shrews are widely distributed throughout mainland Britain, but generally uncommon. They are scarce in the Scottish highlands and absent from Ireland and most of the small islands.
Stoats (Mustela ermine) have Long slender bodies with short legs. Medium to short tail always with a black tip. Fur ginger to reddish brown above, white to cream below, straight line separating the two colours. Some animals turn white or partially white in winter (known as ‘ermine’).
Habitat: Deciduous wood mix, conifers, urban & gardens, Rivers and wetland, Coastal & marshland, Grassland, Mixed woodland, Heathland, Arable land
Size: Males 275-312 mm; females 242-292 mm. Tails 95-140mm
Weight: Males 200-445g; females 140-280g.
Origin & Distribution: The stoat occurs throughout Britain and Ireland, living in any habitats at any altitude with sufficient ground cover and food. The stoat’s presence on offshore islands depends upon prey availability.
General Ecology: Stoats don’t like to be out in the open and so tend to hunt along ditches, hedgerows and walls or through meadows and marshes. They search each likely area systematically, often running in a zig-zag pattern. All but the largest prey is killed by a single bite to the back of the neck. The nests of former prey are taken over as dens which may be lined with rodent fur in colder climates. Within its territory the resident stoat will have several dens which it uses periodically. Male and female stoats live separately, marking their territories with scent. These animals will defend their territory against intruders of the same sex, but in spring the males’ system breaks down as they range widely in search of females.
Diet: Stoats feed mainly on small mammals, especially rabbits and water voles where these are abundant. Small rodents are also taken, supplemented by birds, eggs, fruit and even earthworms when food is scarce.
Lifespan: Can live up to around 5 years, or 6-8 years exceptionally, but usually don’t survive beyond 1-2 years old.
Breeding: Although females (including this year’s kits, which may be only 2 – 3 weeks old) are mated in early summer, they do not give birth until the following spring because implantation is delayed for 9 – 10 months and active gestation is only 4 weeks. A large litter of between 6 and 12 young is born – blind, deaf and barely furred. The female feeds them for up to 12 weeks, by which time they are developing into efficient hunters.
Conservation Status: Stoats are legally protected in Ireland but not in the United Kingdom. For many years gamekeepers and poultry farmers have attempted to control stoats. An animal getting into a shed or pen can and will kill every bird it catches. Such attacks are typical behaviour for many small carnivores faced with vulnerable prey. Trapping is less intensive than it used to be (stoats were also taken for their skins, especially when in ermine) but it appears that this had little long-term effect on numbers as natural mortality is usually quite high in stoat populations.
Origin & Distribution: Widespread throughout Britain, weasels are our smallest and probably most numerous carnivores. However, they are absent from Ireland and most off-shore islands. They are found in a wide range of habitats which include urban areas, lowland pasture, woodland, marshes and moors. Weasels are less common where their prey are scarce, such as at higher altitudes and in dense woodland with sparse ground cover.
General Ecology: Dens are usually nests of former prey taken over by weasels, and may contain the remains of food from several days meals. In cold climates the nests are often lined with fur from lemming prey. A weasel’s home range usually contains several dens and resting places that are visited at intervals. Weasel home ranges vary in size according to the distribution and density of prey. Male and females live in separate territories, male ranges being larger. Resident animals of both sexes may defend exclusive territories at times when numbers are high and neighbours numerous. In spring males extend their range to seek mates.
Diet: Weasels specialise in hunting small rodents. The weasel’s small size enables it to search through tunnels and runways of mice and voles. Access to tunnels means weasels can hunt at any time of the day or year. They do not hibernate and can hunt even under deep snow. Additional prey such as birds, eggs and young rabbits may be taken, particularly if rodents are scarce.
Lifespan: Only around 10% survive to over 2 years old.
Breeding: Usually only one litter, of 4-6 young are born per season, but two litters in years when field voles are abundant. Young are weaned at 3-4 weeks and can kill efficiently at 8 weeks; in a good vole year, young females can breed at 2-3 months old. Family groups split up at 9-12 weeks.
Conservation Status: Traditionally weasels have been considered enemies of gamebirds and gamekeepers have exercised intensive predator control, trapping and killing many weasels along with other carnivores. Weasels do kill some gamebird chicks, but probably very few. Weasels have no legal protection in Britain. Trapping probably has no long term effect: weasel populations are very resilient, and they naturally suffer high mortality. In bad rodent years many weasels starve and few of the survivors breed. Local populations often experience extinctions. However, weasels are extremely good at recolonising abandoned areas when conditions improve.
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