Guide to locating and sexing deer foetus?

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willie_gunn

Well-Known Member
It doesn’t necessarily work that way though does it?

I find it a bit weird as looking at the deer foetuses from culled does won’t necessarily tell you what the sex of foetuses remain In The unculled does…..

Foetus sex is a bit of a lottery rather than by design isn’t it?
I am not sure that’s the case.

I thought research such as that by Hewison and Gaillard suggested that sex ratios of offspring were, in roe at least, affected by local resource competition. As body mass of fecund females rises, so the proportion of male embryos reduces.
 

willie_gunn

Well-Known Member
The more pressure the deer are under the more doe foetuses you will find. A survival mechanism to pass on genes.
Though I don’t think that’s what the research shows?

https://watermark.silverchair.com/7-4-461.pdf?

“The bias in favour of producing make offspring increases as habitat quality decreases.”

Of course habitat quality may not be the same as what is meant by “under pressure”, i.e. if the population size in aggregate is reducing, it may well be that more female offspring are produced.

Would be interesting to look at more research if anyone has some links?
 

baguio

Well-Known Member
Though I don’t think that’s what the research shows?

https://watermark.silverchair.com/7-4-461.pdf?

“The bias in favour of producing make offspring increases as habitat quality decreases.”

Of course habitat quality may not be the same as what is meant by “under pressure”, i.e. if the population size in aggregate is reducing, it may well be that more female offspring are produced.

Would be interesting to look at more research if anyone has some links?
There's a detailed study of Red deer on the island of Rum. I'm sure that they came to the conclusion that poor hinds usually produced female calves. Hard to say whether this was because female calves put less strain on the hind due to a lower requirement for milk or because the female calf was sure to pass on the genes whilst a poor male calf would be unlikely to ever breed. Are deer able to decide on the sex of their unborn foetus?
They definitely did state that stags with large antlers father more offspring which is probably not that surprising really.
 

willie_gunn

Well-Known Member
There's a detailed study of Red deer on the island of Rum. I'm sure that they came to the conclusion that poor hinds usually produced female calves. Hard to say whether this was because female calves put less strain on the hind due to a lower requirement for milk or because the female calf was sure to pass on the genes whilst a poor male calf would be unlikely to ever breed. Are deer able to decide on the sex of their unborn foetus?
They definitely did state that stags with large antlers father more offspring which is probably not that surprising really.

Thanks - I’ll try to track that down.

I did find this: Population density affects sex ratio variation in red deer - Nature

“The proportion of males born each year declined with increasing population density and with winter rainfall, both of which are environmental variables associated with nutritional stress during pregnancy.”

So perhaps not so much deer consciously deciding on the sex of their offspring, rather the environmental conditions affecting available nutrition, which in turn influences the sex of the foetus?
 

Freeforester

Well-Known Member
Indeed, I’d be interested to know the thinking behind that….
Predictive trends/cohort analysis type of modelling, helps inform the picture of the sex ratio of the population, had you not intervened. Phil Ratcliffe et al did a lot of work on this in the eighties, but I agree it may be of limited interest to the majority of stalkers.
 

baguio

Well-Known Member
Thanks - I’ll try to track that down.

I did find this: Population density affects sex ratio variation in red deer - Nature

“The proportion of males born each year declined with increasing population density and with winter rainfall, both of which are environmental variables associated with nutritional stress during pregnancy.”

So perhaps not so much deer consciously deciding on the sex of their offspring, rather the environmental conditions affecting available nutrition, which in turn influences the sex of the foetus?
Only gives brief information but Tim Clutton-Brock co wrote the book I read. Interesting even from this that close incest drastically reduced the chances of the calf living beyond 12 moths of age. I have read on here that it didn't matter in deer. Clearly it does!
 

pop1

Well-Known Member
Indeed, I’d be interested to know the thinking behind that….
It’s actually quite interesting after a few years, does tend to back the theory that it’s a 50/50 split between hind and stag calving ratios. Give or take 1 or 2 either way
 

25 Sharps

Well-Known Member
Ha, my dream is to keep the fallow population size static. Reduction? Probably impossible now.
Careful what you wish for, look at what is happening in Scotland.

Also you are talking about specific areas, there is not a huge population everywhere, I’d quite like the fallow to expand locally, only see them on my ground occasionally and that’s groups of 2-5.

But I get locally to you the population may be increasing and causing problems locally. I’d also guess some people stopped shooting them as they couldn’t get enough return in the last year.
 

PorkChops

Well-Known Member
Also you are talking about specific areas, there is not a huge population everywhere, I’d quite like the fallow to expand locally, only see them on my ground occasionally and that’s groups of 2-5.
In the last 35 years, numbers have grown from hardly any, through groups of 5 (about 15 years ago) to groups of 50+ now... I think mainly down to pockets of unstalked land and a general preference for shooting bucks.
 

25 Sharps

Well-Known Member
In the last 35 years, numbers have grown from hardly any, through groups of 5 (about 15 years ago) to groups of 50+ now... I think mainly down to pockets of unstalked land and a general preference for shooting bucks.
Yes, the preoccupation for shooting bucks amd managing for ‘good genes’ is undoubtedly a big part of the equation.

Have only ever seen one doe on my patch in the last 7 years and have only seen fallow a handful of times
 
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