Calf Mortality After Cow Dies

[D_Walt]

When my daughter was about kindergarten age we were sitting in a deee stand when a doe and a fawn came out. Conversation as I recall:

Daughter: Daddy shoot the doe!
Me: no, she has a fawn with her
Daughter: will the fawn die if you kill its momma?
Me: Yes
Daughter: (10 second pause) Daddy, shoot them both.

No shots fired that day.

For whitetails on the place I manage we do not shoot does until after Thanksgiving due to research showing drastic difference in mortality of fawns losing their Mothers in October vs Dec. (our deer rut late December, fawns born in July usually)

 

[Nick87]

When my daughter was about kindergarten age we were sitting in a deee stand when a doe and a fawn came out. Conversation as I recall:

Daughter: Daddy shoot the doe!
Me: no, she has a fawn with her
Daughter: will the fawn die if you kill its momma?
Me: Yes
Daughter: (10 second pause) Daddy, shoot them both.

No shots fired that day.

For whitetails on the place I manage we do not shoot does until after Thanksgiving due to research showing drastic difference in mortality of fawns losing their Mothers in October vs Dec. (our deer rut late December, fawns born in July usually)

Years ago when I first started bowhunting in high school I shot a doe the first week in October. Watched her for probably 45 min. No sign of any fawns. Watched her fall and then went back to the truck to put my bow away and get a light. When I returned there was a (very small for that time of year) fawn standing by her bleating. I don't know if that fawn was like a 2nd or 3rd cycle fawn or what. That has stuck with me the rest of my life. If I do shoot a doe it's later in the season now when they are grouped up.

 

[Dakotakid]

Hunted private with two cow tags last year. I asked whether the ranch preferred I take cow/calf or two cows. They requested I take two cows. I talked to fwp warden later regarding mortality on the calf crop and was told by late fall the survival rate is on par with weened calves per the biologist. I was also told the ranch I hunted does that to try to keep more bull calfs because the range manager outfits.

I took one cow.

 

[tormenter]

I will typically take a yearling or calf if I have a cow tag. My father said if you shoot a calf you only kill one elk, but if you shoot a cow then you will be killing 2 elk as she is most likely pregnant by rifle season.

Makes sense to me and there would no guarantees the calf would survive the winter with or without its mother. Calves and yearlings are much easier to pack out.

 

[sapperJ24]

I'm still looking for an applicable study. There are a handful of studies that look at additive v. compensatory effects of hunting and predation, but I have not found one that looks at the loss of the cow on calf survival.

This study (amusingly, same authors as the seal study) looked at models incorporating vital rates and harvest into population projections. As other studies have shown, middle-aged elk moms do best at rearing. They mentioned indirect effects of harvest including wounding, but did not discuss the impact of the loss of the mother on calves. Not sure why your question isn't discussed, maybe it has no effect, or maybe it didn't occur to the researchers.

"Moreover, our assumption of simple additional harvest mortality overlooked a potentially substantial source of mortality on hunted populations; where legally reported harvests underestimate the impact of hunting because of unreported wounding loss (Slabach et al. 2018), harvest mortality may be a super‐additive process"

 

[jimh406]

After a short period, the calves are with the herd group along with the cows. I think that generally happens before hunting season.

Fwiw, I've seen Mule Deer does pick up additional fawns during Summer. My guess is something happened to the doe that was the mother of the other doe. Not a scientific measure, but I'll see a doe with fawn or doe with two fawns day after day at about the same time, and then an additional fawn or two will start traveling with that group.

 

[BuzzH]

I'm still looking for an applicable study. There are a handful of studies that look at additive v. compensatory effects of hunting and predation, but I have not found one that looks at the loss of the cow on calf survival.

This study (amusingly, same authors as the seal study) looked at models incorporating vital rates and harvest into population projections. As other studies have shown, middle-aged elk moms do best at rearing. They mentioned indirect effects of harvest including wounding, but did not discuss the impact of the loss of the mother on calves. Not sure why your question isn't discussed, maybe it has no effect, or maybe it didn't occur to the researchers.

"Moreover, our assumption of simple additional harvest mortality overlooked a potentially substantial source of mortality on hunted populations; where legally reported harvests underestimate the impact of hunting because of unreported wounding loss (Slabach et al. 2018), harvest mortality may be a super‐additive process"

I don't think you'll find one mainly because there are too many variables.

For instance, if a cow is killed early, and the calf is on its own and is killed by a predator, well, that's predation that killed it. Who knows if that same calf would have lived if the cow wasn't killed.

The studies conducted on calf mortality point to the main factor being predation, the hard thing to know is why the calf fell victim to a predator? Was it because its mother died earlier or was it just by chance?

I rarely see lone calves wandering around while hunting, as in, I can only think of one specific case (during general season).

I would have to think that if calves were dying after the cow being killed, I would see it happening. I just don't.

But, I still try not to shoot cows with calves and for the most part, I've been pretty successful not doing so just by taking a few minutes to look them over.

 

[squirrel]

Speaking locally the techniques of catching/collaring would make it almost impossible to keep track of "pairs". The helicopter swoops into 50-100 nets one scatters 49-99 to the wind and then collars the one and heads off to the easiest looking remaining target. 3 hrs later they have a 5 mile radius of 3-5 collared elk and busted fences for another 5 miles radiating outward.

They do collar calves and anecdotally they always look like they are on deaths door by march compared to un-collared. It also seems that more often than not the collared ones don't have ma right with them and are either alone within the herd or with the spike bull groups. One would have to wonder if the helicopter chase plays a role in this. Bring it up at a meeting if you want to witness CYA in action, Khaki version.

Most calves try to stay with the herd but there isn't much "adopting " takes place. they get left over snow excavations, after anything worth while has already been chomped. A cow will dig and share with her own calf, anyone else gets a hoof whack to the head.

In a resting herd it is very easy to tell pairs, take the calf or take a solo cow would seem to make sense but most hunters pick the biggest tan rectangle and unload. After the first report there's no chance, it looks pretty much like when the helicopter swoops in.

 

[nrpate05]

I think it depends almost 100% with predator density and if the calves are left on their own or can keep up with the rest of the herd. I also think later in the year it's less of an issue and most survive because they've moved to winter range.

That said, I try hard to not shoot cows with calves. I try to pick 1.5 year old cows or ones standing away from the main herd with no other elk near them. It's pretty obvious even in large herds to recognize the cow/calf pairs.

Do you have a good method for picking out a young cow? Is it a size thing or something else? Curious as I've never been able to tell, but my experience is somewhat limited.

 

[BuzzH]

Do you have a good method for picking out a young cow? Is it a size thing or something else? Curious as I've never been able to tell, but my experience is somewhat limited.

Short face, lanky looking, smaller body size for 1.5 year old cows. Picture a spike bull but the cow version.

 

[Ben Lamb]

Some good stuff out of Idaho on elk survival over winter amongst wolves. It's not specific to a calf losing a cow and surviving, but it does paint a pretty good picture of what is needed for a calf to survive the winter.

Body condition matters. Having a mom to show you what to eat and how to hide helps all of that. Biologically, I doubt that taking a cow w/ a calf will hurt the overall herd dynamics. By the time rifle season rolls around those calves are mostly independent. Some exceptions apply, of course.

 

[Bambistew]

Not sure how applicable it is to elk, but I believe Alaska F&G has done a few studies on moose calf survival. Many/most cow permits here prohibit the taking of a cow with a calf unless the unit/area is over populated, then it doesn't matter because calf mortality is high and they want the population to decrease with its added mortality. I presume predation is high, but starvation is probably a close second. I would imagine having a full grown adult to plow trails in the snow is a huge advantage too.

I believe they've also done studies on caribou. cow/calf survival.

I think they 'd have be pretty naïve to believe that killing the mother cow elk doesn't have an effect on calf mortality, how you categorize death based on that variable it is the hard part.

It really seems like it would be a nightmare to create a dry cow only type harvest for elk, and I'm guessing they just work in the mortality of the calf into the management. Moose are easy because they aren't necessarily herded up like elk, however in the fall I've seen 20-30 cows together at once. But the calves tend to stick close to the cows and you can sort them out.

 

[sccritterkiller]

That’s why you double when you have two cow/calf tags! The cow/calf combo is the way to go! That calf meat is tasty and I wouldn’t want it to suffer all winter!

I always cow hunt with my buddies dad, He is in his late 70s. He is all about filling his tag on calf..."Easy to pack out and easy to to chew..perfect for fella of my vintage." One of my favorite hunts every year, even if we eat our tag.

 

[COEngineer]

Not sure how applicable it is to elk, but I believe Alaska F&G has done a few studies on moose calf survival. Many/most cow permits here prohibit the taking of a cow with a calf unless the unit/area is over populated, then it doesn't matter because calf mortality is high and they want the population to decrease with its added mortality. I presume predation is high, but starvation is probably a close second. I would imagine having a full grown adult to plow trails in the snow is a huge advantage too.

I believe they've also done studies on caribou. cow/calf survival.

I think they 'd have be pretty naïve to believe that killing the mother cow elk doesn't have an effect on calf mortality, how you categorize death based on that variable it is the hard part.

It really seems like it would be a nightmare to create a dry cow only type harvest for elk, and I'm guessing they just work in the mortality of the calf into the management. Moose are easy because they aren't necessarily herded up like elk, however in the fall I've seen 20-30 cows together at once. But the calves tend to stick close to the cows and you can sort them out.

As you point out, they're not the same. Elk are much more gregarious than moose, but maybe not as much as deer(?).

Similar to what someone else observed, I watched a backyard doe with twins pick up a third fawn for a few weeks. Then the 3rd fawn 'disappeared' and eventually the smaller of the original twins also 'disappeared.' Hard to know from those observations if the doe actually adopted the third fawn or if it just tagged along until it couldn't keep up.