Adult males (stags) grow to 70 - 95cm at the shoulder and weigh 40 - 70 kg. Females (hinds) are 50 - 90cm at the shoulder and 30 - 45kg, dependent on subspecies.
Sika are similar in size and coat to Fallow deer, but darker. They are reddish-brown to yellow-brown in colour with a dark dorsal stripe surrounded by white spots in the summer. During winter, they are dark grey to black and the spots are faint or absent. They have a very distinct white gland on the lower back leg. Their tail is shorter and with a less distinct stripe than fallow deer.
Antlers are branched and similar to red deer but usually with a maximum of eight points. The bay tine is also absent. The angle between the brow tine and the main beam is usually less than 90o.
History, distribution & habitat
Sika were introduced from the Far East into Britain in 1860. While several subspecies, including Chinese, Japanese, Formosan and Manchurian, were introduced into parks the only free-living form in Britain is the Japanese sika. It is possible that almost all (if not all) living English, Scottish and some Irish sika are descendants from only one stag and three hinds introduced to Viscount Powerscourt's deer park at Enniskerry, Eire in 1860.
The preferred habitat is coniferous woodlands and heaths on acid soils. Distribution is widespread and expanding in Scotland from west to east with a strong population in Peebles-shire. They are patchy in England (bands exist across the north and south) and Northern Ireland (in County Fermanagh and County Tyrone).
Sika graze on grasses and dwarf shrubs, especially heather, although coniferous tree shoots and tree bark may occasionally be taken in small quantities. Browsing of tree shoots and agricultural crops and bark stripping and bole scoring (gouging with the antlers) of plantation trees puts sika in conflict with farmers and foresters due to economic damage. Conversely, many country and forest estates can gain substantial revenue from recreational stalking and/or venison production. Whether in conflict or used as a resource, sika populations require careful management to maintain health and quality and ensure a sustainable balance with their environment.
Breeding, behaviour & lifecycle
The breeding season, or rut, occurs from the end of September to November. The environment has a strong influence on mating strategy. Typically stags defend a rutting territory, much like fallow deer, and they may also switch to harem-holding when a group of hinds has been assembled. Less typically, males may congregate to form a lek or may simply wander throughout the hinds' range in search for receptive hinds.
A single calf is born during early May to late June after a gestation period of 7 ½ months. They can live, exceptionally, up to 18 years.
Sika are fairly unsocial, tending to be solitary for most of the year and only forming small groups in winter. The sexes are strongly segregated and occupy discrete geographic ranges for most of the year, only coming together to mate.
Sika are becoming regarded as a pest in areas of conflict since the damage that they cause is serious and the rate of hybridisation with red deer alarming. Hybridisation appears to be most pronounced at the edges of population ranges where both species meet. The first cross between the species has the appearance of both parents, but subsequent crosses result in the hybrid having the dominant parental appearance. This makes selective culling impossible, potentially reduces income from sport shooting and poses a major threat to the genetic integrity of native red deer. Indeed, some would say that there are no pure bred red deer surviving in mainland Britain and only sika in the New Forest and Peebles-shire remain pure.
Sika have a wide repertoire of vocalisations. Stags groan, blow raspberries, yak-yak and give a high-pitched whistle during the rut or can emit a startling scream! Hinds with calves whine and calves reply with a bleat or squeak. When alarmed both sexes give a short, high-pitched bark.
Sika are active throughout the 24-hour period but are more active during the hours of darkness in populations experiencing frequent disturbance.
Sika deer. R.Putman (2000) The Mammal Society, London and the British Deer Society, Fordingbridge.
Distribution and current status of Sika Deer, Cervus Nippon, in Great Britain – this can be downloaded from the Wiley online Library http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2907.1987.tb00047.x/abstract