Sika Deer - INNS Week 2022
I think myself as petty good at identifying British animals especially birds and mammals by sight and field signs, but I am not familiar with all the sounds they make. Whether it be bird song or the calls used by mammals. It's partly that I do not regularly hear these sounds for them to become stuck in my memory. However, many years ago whilst on holiday in the area of Loch Ness in Autumn I stopped at dusk to use my bat detector. That's when I heard a whistling sound ending in a throaty gravel, it was very eriery and almost sent a shiver up my spine. I could not place the sound and thought it must be a bird. As I began to search the area I saw a few deer with spotted coats and others with darker coats. Fallow deer are known to come in lots of different shades so I thought this was what I had stumbled upon, but the antlers on the male looked more like those of a red deer. I had found my first Sika deer.
The whistling noise came again and it was obvious it was the buck calling, not a sound I would have ever expected from a deer. Sika Deer are not native. The free roaming population came from escapees from various deer parks across the UK which first kept them in the 19 century with stock drawn from Japan and Taiwan. However, it is only the Japanese race that has established itself in the wild. There are restricted local populations in England, notably in the New Forest, Bowland in Lancashire and the Poole basin in Dorset. There are also small expanding populations in Northampton, Bedfordshire, Oxfordshire and the Wiltshire / Gloucester borders. They are widespread in Scotland with strongholds in Argyll, Inverness-shire, Peebles-shire, Sutherland and Ross and Cromarty.
Not only do they compete for food with other deer species they can, and do, cross breed with our native red deer with both species producing fertile offspring. This might seem surprising when you compare the size of both species! A red deer body is about 2.40m were as sika are just under 2m, but surprisingly they are both about the same size measured from the shoulder, 100-120cm. This has led to worries of the hybridisation of the red deer population in the UK where Sika are present. It can be difficult to determine which animal is in fact a hybrid unless you know the special characteristics of both species very well. For example you could say that antlers and a darker coat in winter are a red deer, when it’s in fact a Sika! The tell-tale give away is a white spot on their hind legs just below the knee joint. They can also be mistaken for fallow due to the spots which are present in the summer coat, additionally from the rear as both have white rumps with some black borders. The only difference is that in Sika the black is just around the top where as in fallow it also is seen down the sides.
Due to the issue of hybridisation and damage to forestry and farming most populations are monitored and numbers controlled. They are on schedule 9 of the Wildlife and Countryside Act 1981 so translocation to areas outside their known range is illegal and they cannot be introduced to specific Hebridean islands that have “pure” Red deer. In my own county of Staffordshire we have pure red deer and so worry over captive Sika deer escaping and breeding with our wild Reds.
Therefore we need to establish the spread and current presence of the Sika deer across the UK so that we can fully understand its impact on the countryside. You can help us to do this by recording your sightings on the Mammal Society’s Mammal Mapper app.
This blog comes from mammal expert Derek Crawley. Derek is a valued active member of the Mammal Society, he is Vice Chair and the Training Committee Chair. Additionally, he is the current Chair of the Staffordshire Mammal Group and a Regional Coordinator for the National Harvest Mouse Survey. All photos in this blog were taken by Derek himself.