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Thread: Sika Twins and early calves

  1. #1

    Sika Twins and early calves

    Has anyone on the site seen a Sika hind with twins. I personally have only seen a hind followed by two calves once although I have gralloched several with twin foetus's or is it foeti in the Borders region. What's the earliest for a calf seen with it's mother,mine was April 8th suggesting August mating,when the odd whistle is heard, the rut being a protracted affair from then until late November. The theory on that one being that early born hind calves can come in season by November if they reach the correct weight thus keeping the stags interested.
    Honour all men, Love the Brotherhood, Fear God, Honour the Queen.

    Keep the Faith.

  2. #2
    I've never seen sika twins in the wild (once in a park) but heard reports of a pair in Inverness-shire year before last, they were very wee thus culled.

    I've only seen May calves (with spots) but I gather there is roughly a six week + range which reflects the longer (than red) rut.

  3. #3
    I'm not known for my ability to count but by my reckoning an April calf would be conceived early Sept based on 30 weeks/210 days. The rut is well advanced by mid sept. Here in Ireland late calving is more of a feature.
    Ion

  4. #4
    Most of the research into this is Japanese, but the results are remarkably consistent across all of Japan with a wide range of body sizes and climates and the results also match what I've observed.

    The gestation period of sika based on captive deer was determined to be 231 days. Research on wild sika gave a gestation period of 231.6 days.

    It is found that large variations in the date of conception may be seen but that there tends to be a very marked peak and it is interesting to note that the peak in the Japanese studies (22nd October in the particular one I'm looking at for this info) would also be reasonable for the UK. Several Japanese studies found the range of dates of conception to be as follows:

    7 Oct - 17 Jan
    8 Sept - 11 Dec
    9 Sept - 23 Jan
    12 Sept - 22 Dec

    The date on which calves are born, and these are based on different studies to the ones above and so will have had slightly different distributions of conception dates, was found to peak in late May/early June but in some studies calves were born as early as April and as late as November.

    Interestingly the view in the Japanese research is that the rut "occurs immediately after the peak of fat deposit of male sika deer." So while we always look to the current weather conditions to provide info on the progress of the rut it may be that it is actually driven by the conditions required to lay down fat in stags and, in turn, this may depend on the weather or other conditions across the whole summer period.

    In terms of twins one researcher had seen only two cases of twins in 15 years while another reports the twinning rate to be 0.29%. In a deer farm in China the twinning rate was reported to be 10.4% and this was attributed to long term selective breeding to improve the farm stock rather than to nutrition or other factors.

    Hopefully someone finds that interesting. I'm just reading this stuff in a book and make no claims to being an expert so the best I can say is that this fits with my experiences.
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  5. #5
    That is interesting, thanks for posting Caorach - what book is it out of interest?
    I have a few pamphlets but now that Muntjac have their own book (C. Smith-Jones) it's about time someone wrote one on sika management, who though? I guess it's not easy as their behaviour does seem to differ depending on which herd they are from.

  6. #6
    Thanks for the info Caorach, all very enlightening but we are told that it is the body weight of the hind which determines when she comes into oestrus thus determining the date of the rut. Having managed Sika for a number of years they like our oriental cousins are inscrutable and very hard to account for in most cases. Having said that they can also be so stupid that you can't believe your luck sometimes. They also tend to vary their habits from area to area even when only a mile or two apart and from the same original stock. You can spend many fruitless hours stalking them but when you get some knowledge of their behavior in an area it becomes easier. We as professional Keeper/Stalkers used to reckon on 10 hours per beast at any time other than the rut. This was however disproved by my wife who studied them closely and shot seven hinds in the same block in 10 hours. I remember it only too well as I had to extract and larder them.
    There is a book by Doctor Bruce Banwell appertaining to Sika in New Zealand but unfortunately it didn't seem to apply too well to the Borders population. It would be interesting if someone would have a go at writing a paper on them.
    Honour all men, Love the Brotherhood, Fear God, Honour the Queen.

    Keep the Faith.

  7. #7
    Quote Originally Posted by NickJ View Post
    That is interesting, thanks for posting Caorach - what book is it out of interest?
    I have a few pamphlets but now that Muntjac have their own book (C. Smith-Jones) it's about time someone wrote one on sika management, who though?
    I think it has been done as the book I'm referring to is "Sika Deer - Biology and Management of Native and Introduced Populations" it is, basically, a collection of scientific papers and some well researched general contributions. There is a chapter on Sika in the British Isles by Rory Putman and Graeme M. Swanson for example. It is very expensive but available second hand for much more reasonable money, though still a lot of cash for a book, but is well worth it for anyone who is serious about their sika. It has given me a lot of insight into what I'm seeing with the deer and also put to rest some stuff which I believed to be true but which either isn't true or is far from as simple as the stated truth. My intention was to sell it again after reading it to recoup some of the cost but it has been so interesting and useful that I'm keeping it.
    For self catering accommodation on the Isle of Lewis please visit:
    http://www.7south.co.uk/




  8. #8
    Quote Originally Posted by The fourth Horseman View Post
    There is a book by Doctor Bruce Banwell appertaining to Sika in New Zealand but unfortunately it didn't seem to apply too well to the Borders population. It would be interesting if someone would have a go at writing a paper on them.
    I found that the Japanese research actually applied very well to the populations of sika that I see - it wasn't a precise fit in terms of detail but the actual patterns were very interesting. As an example sometimes the sika I stalk vanish in the winter and there is some interesting info on sika migration which provided me with a lot of insight though the main reason for the Japanese sika migrating is deep snow, which doesn't apply here, with lack of food being a secondary reason. I my case I suspect lack of feeding is the primary reason for them moving out and my patterns of movement fit almost exactly with the Japanese ones though until I saw the Japanese ones on paper I wasn't getting the full picture of what my deer were doing but on reading the paper a lightbulb came on for me.

    My recollection is that the Japanese papers do not make a direct connection between hind body weight and oestrus but rather conclude something along the lines of "a hind generally does not conceive unless the nutritional situation on the ground is sufficient to support a calf." I think the Clutton-Brock study of reds on Rhum goes into this in more detail, and states the body weight thing quite explicitly, but am not going to grab it now to refresh my understanding of exactly what he said. So my general understanding is that the body weight thing is sort of true, but not the complete story, but without re-reading everything again this conclusion may be based on faulty memory on my part.
    For self catering accommodation on the Isle of Lewis please visit:
    http://www.7south.co.uk/




  9. #9
    During the past 13 years I have been culling a substantial numbers of sika and can only ever remember 3 sika hinds that I shot having twin embryos. This will equate to a very low percentage. I have noticed that there seems to be a large variation in calf sizes. I feel that this is possibly due to the sika rut appears to start and stop then start again.
    Last edited by rem284; 29-07-2014 at 12:57.

  10. #10
    I agree with you on the stop start of the rut, which is why I believe well developed hind calves will promulgate stag activity up until December if they come in season. It would also account for the difference in calf sizes. In the past I have heard stags start whistling in mid August and have seen a young stag whistle in very late November. Hopefully I may get among some later this year.
    Honour all men, Love the Brotherhood, Fear God, Honour the Queen.

    Keep the Faith.

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