Sika deer, cervus nippon, are native to Asia. They are held sacred in Japan, but in China they are hunted for their antlers, which are used in traditional medicine. An attractive species with a spotted chestnut coat, they were introduced to Britain in the 19th Century in a number of parks across the country. This was down to the influence of the 7th Viscount Powerscourt, who introduced all sorts of exotic species to his park near Dublin. The sika bred very well, and soon the Viscount was exporting them to landowners all over the British Isles. They were exhibited in 1860 in Regent's Park in London.
Escapes and deliberate releases into the wild occurred frequently, and today there is a large wild population concentrated in two wide bands; one each across the north and south of the country. The population seems to be continually expanding. In Scotland, records of sightings as well as reports of established herds are slowly spreading from west to east. In England, they are found in Dorset and the New Forest, in Lancashire and Yorkshire, and also in the localities of parks from which they have escaped1.
Although sika deer are an introduced species and not native to the UK, they are considered a British mammal. Like the ruddy shelduck, mink and grey squirrel, they have a breeding population in the wild that is viable in the long-term, and have a seemingly permanent place among Britain's wild fauna.
The Dorset Population
It is only in Dorset and parts of the nearby New Forest, however, that sika deer are really thriving. Here there is little hybridisation, making the sika deer of Dorset a rare case of an introduced species doing very little harm to native populations.
Sika deer first arrived in Dorset at Hyde House Park, north of Wareham, in 1895. At about the same time they were also placed on Brownsea Island. Popular local legend holds that a large quantity of sika escaped by swimming ashore on their first night of release, and settled in the Poole Harbour Basin. Across the basin, the RSPB reserve at Arne is a good place to find sika, the heathland and woodland there being a perfect habitat for them.
During World War II, the Ministry of Defence took over Hyde House Park and decided to release all the deer. They have settled well into many areas of south-east Dorset. Further east, in the New Forest, a pair of sika were given to John, the second Baron Montague of Beaulieu, by King Edward VII. This pair escaped into Sowley Wood, and a second pair also escaped into Ashen Wood. These were the basis of the large herds of sika to be found in the forest. They were so prolific culling had to be introduced in the 1930s to control numbers.
Sika deer have a reddish-brown coat with white spots in the summer months. They have a short white tail and white rump. The male of the species has four pointed antlers which are shed during April and May.
Sika deer are normally found in woodland and heath habitats, and their diet consists chiefly of grasses, sedges, heather, bark and fungi. They are most active at dusk and are usually solitary, except in the mating season between August and October. At this time, the males make an other-worldly, shrieking whistle which can be heard up to a kilometre away. If you are walking in the woods and hear the shrieking it can be terrifying - it sounds as if a blood-curdling crime has been committed - especially if it is followed by the 'yak yak' noise, which sounds like a witch cackling! If you want to hear these and other deer sounds, there is an excellent website called Deer UK where you can listen to various species.
Sika are reputed to damage trees more than any other deer, stripping bark very efficiently, so can be destructive around crops and forest saplings2. The introduced sika also thrive on much poorer vegetation than native deer, effectively out-competing them - at Luggala in the Wicklow Mountains, Ireland, they have driven the native red deer from the estate. Sika will also breed freely with native red deer, and there are fears that the genetic integrity of the whole Scottish herd has been compromised by the interlopers from Japan.
There have been no major studies to estimate numbers of sika living in the UK3. Whereas there are huge numbers of ornithologists willing to pay membership fees and spend time volunteering, there are comparatively few mammalogists. Comprehensive nationwide projects such as the British Trust for Ornithology's Bird Atlas rarely happen in the world of mammals, and those that do focus on declining species such as the red squirrel or water vole. So no one really knows how many sika deer there are, or if their populations and range are expanding. We can only have an educated guess based on casual sighting and reports from farmers, gamekeepers and walkers. Every sighting is important, so if you do encounter one, please let the Mammal Society or your County Mammal Recorder know!
Bournemouth University has announced a GPS survey of sika deer on MOD land, which it is hoped will improve future management of the population.
Seeing Sika Deer
When the deer are rutting in the autumn, it is much easier to spot them than at other times of year. Early starts are the order of the day; as with most wildlife, deer do not expect to encounter people on their patch at dawn, and being in place as early as possible maximises your chances. They are not creatures which hide away particularly, and although they are shy, if you hang around long enough they may be curious enough to come closer and investigate you! Stags can be located by their smell. To mark out their territory, they often dig out a shallow hollow and mark it with their scent, the smell of which can be quite pungent - it has been frequently described as 'the smell of several pub urinals at closing time'!
1 See also the Deer Initiative's distribution map.
2 Long-term studies in Japan have shown that saplings have three times the density in fenced-off areas compared to open woodland.
3 Estimates put the Dorset population at about 1,000 individuals, and 20,000 in Scotland.