Field guide to the most commonly encountered mammals and birds

Here, we provide some basic information regarding commonly observed species (plus some others about which we have had queries).  

Feel free to contact us by email if you have any questions regarding species you have encountered on the site.

For more information about mammals, we recommend the Mammal Society's species hub, here, and MammalNet here. For birds, excellent resources are available from the RSPB (here) and the BTO (here).


Common UK Mammals All UK Mammals Common UK Birds All Species All Deer

Chinese Water Deer

Scientific name: Hydropotos inermis

Family: Cervidae

Appearance: Chinese Water Deer are small and compact deer, the males (bucks) have no antlers but have large canine teeth which look like tusks and protrude over the lower jaw. They are slightly larger than muntjac but are much lighter in colour.

Size: Height at shoulder 50-55cm; Head and body length 1m; Weight 11-20kg (males), 9-12kg (females)

Natural history: Chinese Water Deer were introduced into various zoos and deer parks in southern England in the late 19th and early 20th centuries. Escapes, releases and translocations have resulted in a wild population that inhabits mainly Norfolk, Bedfordshire and Cambridgeshire but is still spreading. As their name suggests they prefer wetland habitats such as reedbeds, riparian woodland and wet fenland. They feed on weeds and herbs and occasionally grasses. They are active throughout the day and night but there is a peak of activity around dawn and dusk. 

They are largely a solitary species except during the mating season when they may form pairs or small groups. The rut occurs during November and December when bucks will fight for access to does and injuries are a common occurrence. The females give birth between May and July and can produce up to 5 kids, but between one and three is more common. The kids remain with their mother through the winter.


(C) Don Sutherland (shared under a CC BY-NC-ND 2.0 license)


Fallow deer

Scientific name: Dama dama

Family: Cervidae

Size: Adults males are generally 84 – 94 cm at the shoulder and weigh 46 - 94kg. Adult females are 73 - 91cm at the shoulder and weigh 35 - 56kg. 

Appearance: There are four main variations in coat but many minor variations also exist, including a long-haired version found in Mortimer Forest on the Shropshire / Herefordshire border. The common variety is the familiar tan/fawn colouring with white spotting (becoming long and grey with indistinct spots in winter) on the flanks and white rump patch outlined with a characteristic black horseshoe. The Menil variety is paler, lacks the black-bordered rump and keeps its white spots all year. The Melanistic (black) variety is almost entirely black with no white colouration anywhere. Finally, the white variety can be white to sandy coloured and becomes more white at adulthood. The fallow is the only British deer with palmate antlers. These increase in size with age reaching up to 70cm long when the adult is 3 - 4 years old.

Natural history: Non-native but widely-naturalised. Mostly woodland and open agricultural habitats. 

Behaviour depends upon the environment and population density. In most populations bucks maintain a traditional, defended rutting stand. In others, a temporary rutting stand is maintained to attract sufficient does to herd them into a harem. In areas with very high buck densities a lek (a gathering of males engaging in competitive display to attract potential mates) may be formed. In lower density areas bucks may simply seek out receptive females. In common with other large species of deer, during conflict the bucks’ behaviour escalates from groaning and parallel walks to fighting. During the rut bucks groan tremendously and does with fawns give a short bark when alarmed.

After mating, adult does give birth to a single fawn in June or July after a gestation of 229 days. Bucks generally live for 8 – 10 years although they can live as long as 16 years. 

Fallow deer are active throughout the 24-hour period but make use of open spaces during the hours of darkness in populations experiencing frequent disturbance. Peak activity is at dawn and dusk with most daytime hours spent ‘lying up’, where they lie down to ruminate between feeding bouts. (Source:

 (C) Caroline Johnston (shared under a CC BY-NC-ND 2.0 license)


Scientific name: Muntiacus reevesi

Family: Cervidae

Appearance: Adults males grow to 44 - 52cm at the shoulder and weigh 10 - 18kg. Adult females are 43 - 52cm at the shoulder and weigh 9 - 16kg. Small, stocky and russet brown in colour in summer and grey/brown in winter. Bucks have short (10 cm) antlers growing from long pedicles. Antlers are usually unbranched but a very short brow tine is occasionally found in old bucks. They also have visible upper canines (tusks) suggesting that they are a primitive species. Muntjac have two pairs of large glands on the face. The upper pair are the frontal glands, whilst the lower glands, below the eyes, are called sub-orbitals. Both glands are used to mark territories and boundaries. They have a ginger forehead with pronounced black lines running up the pedicles in bucks, and a dark diamond shape on does. The haunches are higher than the withers giving a hunched appearance. They have a fairly wide tail, which is held erect when disturbed.

Natural history: Non-native but expanding. Mostly forests with a diverse understorey. Breed all year round and the does can conceive again within days of giving birth. Bucks may fight for access to does but remain unusually tolerant of subordinate males within their vicinity. Does are capable of breeding at seven months old. After a gestation period of seven months they give birth to a single kid and are ready to mate again within a few days. Bucks can live up to 16 years and does up to 19 years, but these are exceptional. Muntjac are generally solitary or found in pairs (doe with kid or buck with doe) although pair-bonding does not occur. Bucks defend small exclusive territories against other bucks whereas does' territories overlap with each other and with several bucks. They are known as ‘barking deer’ from the repeated loud bark given under a number of circumstances. An alarmed muntjac may scream whereas maternal does and kids squeak. Muntjac are active throughout the 24-hour period but make more use of open spaces during the hours of darkness in populations subject to frequent disturbance. Peak activity is at dawn and dusk. Long periods are spent ‘lying up’, where the deer lies down to ruminate after feeding. (Source:

 (C) nick ford (shared under a CC BY-NC-ND 2.0 license)

 (C) Airwolfhound (shared under a CC BY-SA 2.0 license)

Red deer

Scientific name: Cervus elaphus

Family: Cervidae

Appearance: Adults males are 107-137cm at the shoulder and weigh 90-190kg. Adult females reach 107-122cm at the shoulder and weigh 63-120kg. The summer coat is reddish brown to brown and the winter coat is brown to grey. There are no spots on the adult coat. Stags have large, highly branched antlers and the number of branches increases with age. Antlers can have up to 16 points in wild animals. The angle between the brow tine and the main beam is near to 90o degrees.

Natural history: Well distributed in Scotland and patchily so in England. Mostly woodland and forest habitats but also open moor and hill further north. The breeding season, on rut, occurs from the end of September to November. Stags return to the hind's home range and compete for them by engaging in elaborate displays of dominance including roaring, parallel walks and fighting.  Serious injury and death can result from fighting but this only occurs between stags of similar size that cannot assess dominance by any of the other means.  The dominant stag then ensures exclusive mating with the hinds. Despite being sexually mature before their second birthday in productive woodland populations, only stags over five years old tend to mate.  In woodland populations hinds over one year old give birth to a single calf after an eight-month gestation, between mid-May to mid-July. Puberty may be delayed until three years old in hill hinds, which may give birth only once every two or three years. Some Scottish hill populations suffer heavy infant mortality at and shortly after birth and during their first winter. Lifespan can be, exceptionally, up to 18 years. In woodland red deer are largely solitary or occur as mother and calf groups. On open ground, larger single sex groups assemble, only mixing during the rut and in the Highlands of Scotland large groups may persist for most of the year. Red deer are active throughout the 24 hour period but make more use of open spaces during the hours of darkness in populations experiencing frequent disturbance. Peak times of activity are at dawn and dusk. In the Highlands of Scotland red deer use the open hills during the day and descend to lower ground during the night. (Source:

 (C) Philip Stephens (shared under a CC BY-NC-ND 2.0 license)


Scientific name: Rangifer tarandus

Family: Cervidae

Appearance: Reindeer are large, heavily built members of the deer family. They have a soft coat of a creamy-brown colour with darker legs and rear. Both sexes have antlers which are long and branched at the ends. Males shed their antlers in December/January and females in May.

Size: Head and body 1.05-1.6 m; Tail 10-15 cm; Height at shoulder 1.07-1.22m; Weight 40-55 kg (males), 28-40 kg (females).

Natural history: Reindeer were native to Britain until towards the end of the last glaciation but became extinct as the climate warmed. There are currently two small free-ranging herds in the Cairngorms in Scotland. Reindeer are active all year round and throughout the day, they are herd animals and in some native populations are migratory and capable of moving at considerable speed. The Reindeer rut occurs between mid-September and early October and females give birth to a single calf in May. The young calves can walk within an hour of birth.


 (C) Stravaiger (shared under a CC BY-NC-ND 2.0 license)

Roe Deer

Scientific name: Capreolus capreolus

Family: Cervidae

Appearance: Adults are 60 - 75cm at the shoulder and weigh 10 - 25kg. Males are slightly larger than females. A summer coat of reddish brown turning to grey, pale brown or (occasionally) black in winter. They have a black nose, white chin and white rump patch, and exhibit a bounding gait when alarmed. Males grow short antlers (less than 30cm) which have up to three tines (points) on each. These antlers are shed each Autumn and new ones will begin to grow from November.

Natural history: Widespread in the UK, roe deer are browsers found mainly in woodland and agricultural areas. The rut, or breeding season, occurs between mid-July to mid-August. Bucks become aggressive and maintain exclusive territories around one or more does prior to the rut. Fights between bucks can result in serious injury or death with the winner taking over the loser’s territory or attendant doe. Courtship involves chasing between the buck and doe for some time until the doe is ready to mate. Although mating occurs in this period the fertilised egg does not implant and grow until January. This is thought to be an adaptation to avoid giving birth during harsh northern winters. The gestation period is nine months (four months of no embryonic growth followed by five months of foetal growth) with kids (usually two or three) being born May – June. Initially, young will be left hidden in dense vegetation while the mother goes off to forage, but as they develop they will start to follow their mother around more. Heavy mortality may occur shortly after birth and during the first winter. Roe do not maintain exclusive territories but live within overlapping home ranges. Males mate with several females and females mating with several males has also been observed. Roe deer are solitary, forming small groups in winter. They are active throughout the 24-hour period but make more use of open spaces during the hours of darkness in populations experiencing frequent disturbance. Peak times of activity are at dawn and dusk. Long periods are spent ‘lying up’ where the deer lies down to ruminate between feeding bouts. (Source:

 (C) Philip Stephens (shared under a CC BY-NC 2.0 license)

Sika Deer

Scientific name: Cervus nippon

Family: Cervidae

Appearance: The Sika Deer was introduced to Britain from Japan in the 19th century for deer parks and collections but escapes and deliberate releases have resulted in naturalised populations establishing themselves in several locations around the UK and Ireland. Closely related to the Red Deer they are similar in appearance but more slender and slightly built. Hybridisation with Red Deer has taken place and many, if not most, animals are probably hybrids. When in their summer coat, which is dappled with white spots, Sika Deer may appear more like fallow deer. The distinguishing features of the Sika Deer are a white gland on the lower back leg and the white rump patch which is encircled in black (no black in Red Deer). Antlers are carried by males only and while similar in structure to Red Deer antlers are smaller with a maximum of four points.

Size: Head and body 1.2-1.9 m (males), 1.1-1.6 m (females); Height at shoulder 1.07-1.22 m; Tail 10-15 cm; Weight 40-55 kg (males), 28-40 kg (females)

Natural history: Sika Deer are active throughout the year and the day with activity peaking at dawn and dusk. Largely solitary outside the breeding season although females sometimes form loose groups. They browse and graze mainly on grasses and heather, shoots and leaves of coniferous and deciduous trees, holly, gorse and bark. The rut takes place during October and November and stags have been recorded displaying a variety of mating strategies such as harems, rutting territories and general wandering in search of opportunistic mating opportunities. Females give birth to a single calf in May or June which suckles for about six months but is also taking solid food after about 10 days.


 (C) Michael Day (shared under a CC BY-NC 2.0 license)

White-tailed deer

Scientific name: Odocoileus virginianus

Appearance: Reddish-brown to grey-brown coat, characteristic white underside to the tail, males have antlers with a variable number of prongs.

(C) (shared under a CC0 license)