Autumnwatch at Arne: How Sika Deer came from the Far East to Dorset

Sika deer were introduced into the UK from the Far East in the 1860s. It is claimed all our feral sika are descended from a single family in Eire.

In Dorset they were brought to Brownsea Island in the 1890s. Being good swimmers some escaped to start populations on the mainland.

They were also introduced to Hyde House in Dorset, from where more escaped in the first part of the 20th Century.

Purbeck has one of the highest populations of sika deer in the UK, and it is not uncommon to see large herds, especially around the RSPB Arne peninsula in autumn and winter, where they enjoy the heaths and remaining coniferous woodlands.

Sika are a medium sized deer, up to 82-90 centimetres (32-35 inches) at the shoulder. Stags are larger than hinds (adult females), and quite powerful looking creatures. Hinds are slighter and more cute-looking, round-faced animals.

For most of the year adult male and female deer keep their distance. Stag groups are hierarchical, based on age and size while hind groups are matriarchal, led by a dominant female. While stags may roam more widely, hind groups tend to be more limited in their range.

During the breeding season, from September to November, stags will move into hind areas. This is known as the “rut” and during this time the stags are territorial and jealously guard groups of females (“harems”).

At this time their call, a characteristic high pitched whistle is heard commonly. They will also mark their territory. To do this they smear vegetation with scent secreted from glands beside they eyes and on the back legs.

They also use pits into which they urinate then apply the musk to themselves! Fights between rival stags over territory are aggressive and often long, occasionally resulting in the death of one of the animals.

Rob Farrington, who works for the RSPB at Arne, said: “After creating a shallow scrape in the ground, the males use this as a toilet before covering every inch of themselves by rolling in it!

"With their new cologne applied, they are ready for the girls and call for them, which sounds like a mix between a scream and a squeaky gate. Lucky for us the males like to be seen so they prefer using our farm fields in which to hold territory and most of the fights between rival males occur here.”

Sika hinds produce just one calf per year, giving birth normally in June or July. The calves are dependent on the hinds (or dams) for three to four months.

Although an introduced species, sika deer do have a role to play in helping manage Dorset’s heathlands through grazing. They are also far bolder than our native roe deer and this enables people fantastic opportunities to see wild animals close up.

However, as with all larger grazing mammals, a lack of any natural predators leads to an unsustainable increase in the population, which in turn leads to three serious side effects.

Firstly through overgrazing and trampling they have a huge impact on sensitive habitats and this has a knock on effect on plant life, insects, mammals and birds. Secondly in large and uncontrolled populations the sika deer become unhealthy. Thirdly they out compete the native roe deer.

Because of this the RSPB controls, through shooting, the number of sika deer on its land at RSPB Arne. This has been done for around ten years.

The work is undertaken by hired professional stalkers, who carry out the job humanly and safely.

To keep up to date with all of the autumnwatch news, follow RSPB Arne on: Facebook.com/RSPBEastDorset @RSPBArne www.rspb.org.uk/arne