Bighorns vs Domestic Sheep

[MtnHunter]

I've lived around a small herd of bighorn sheep my entire life. People have always spoken of them as a rare and unique sight to see. They'd be in one part of the canyon, but not another equally as cliffy part a few miles away. In my lifetime, their population hasn't appeared to have grown or expanded in that area.

Internet searches put elk populations currently at around 1 million in NA. In the early 1900's, populations were around 40,000.

Around the turn of the 19th century, the internet tells me there were an estimated 1.5-2 million bighorns. Currently estimates are at around 70,000. With the prevalence of observable elk nearby, it doesn't seem like a huge stretch to imagine there would likely have been bighorns on pretty much every cliffy area around, at every elevation, and in higher numbers than elk.

How have elk populations apparently flourished through conservation, while bighorn populations have appeared to remain stagnant or even shrink? The North American Model of wildlife conservation has appeared to have worked wonders for elk. Is it alone not working for bighorns? Something isn't adding up to me.

I'm embarrassed to say I've been ignorant of anything to do with bighorn sheep conservation for most of my life. Only in the past few months have I been tying to Google some of these answers. I'm sure many of you are very familiar with this issue, so I'm curious to hear what you know.

I came across this film that suggests that domestic sheep may be a culprit in that they transmit something called M. Ovi to bighorns:

. The sense I get from it is something akin to Europeans coming to America and giving natives smallpox. The fact that comments have been turned off on this video tells me this is a contentious issue, but I wish to learn more from both sides to understand why we are where we are.

Thinking back to the canyon where I've known bighorn sheep to live, there are indeed domestic sheep at the end of the canyon where the bighorns don't seem to go. I'm sure this is a simplified view, but are those domestic sheep really the reason why bighorns aren't expanding into more of their historical habitat? And if domestic sheep interactions are the primary culprit to bighorn dieoffs, there must be some individuals and groups working very hard to keep bighorns from extinction.

 

[MattB]

Disease is a very significant issue with bighorns. Here in CA we have had some very significant die-offs in recent years from respiratory diseases. Contact with livestock is assumed to be behind the disease transmission.

 

[Tmac]

Domestic Sheep will essentially eliminate BH. 90-95% mortality from pneumonia iirc. So in areas used by domestic sheep, regardless of habitat, few if any BH will roam. It’s something wildlife agencies and a number of groups are very aware of and do work at.

 

[LoggerDan]

I’m not sure and I’m not going to pretend to know. But I do know that some animals are just more tenacious to thriving. Think about animals extending their non historic ranges or animals introduced. Coyotes crossing the Mississip or coming to Alaska. English starlings. Himalayan blackberries or kudzu. And i have definitely noticed the expansions of whitetails and have witnessed two whitetail does bullying a family group of mule deer doesff of green feed.

Some of the proposed figures for wildness pre Colonial expansion I have a hard time buying and so by extension I have a hard time believing any of them for the same reason. They say there are more whitetail and more trees than before Columbus. How do they know?

Elk can be very dominant. I know mule deer suffer as elk populations get bigger. Maybe it’s the same for sheep. Maybe elk are just a heartier animal. But sheep everywhere are having a hard time in North America. If a fellow believed in any form of evolution, maybe he could rationalize the theory that maybe sheep are just going away on their own.

On a side note; I have done quite a bit of reading on the Lewis and Clark explorations and I cannot recall ever reading about moose. The country crossed is Shira‘s moose country, but Meriweather , a careful naturalist, never makes mention of them and I don’t think he preserved and shipped a specimen back to Washington, like he did with so many other animals, birds, fish and plants. He does say that the sheep were not as numerous as antelope and elk, which was also a plains animal.

 

[MtnHunter]

Disease is a very significant issue with bighorns. Here in CA we have had some very significant die-offs in recent years from respiratory diseases. Contact with livestock is assumed to be behind the disease transmission.

Are domestic sheep known to be the only culprit? Or is it all or other livestock as well?

 

[MtnHunter]

Domestic Sheep will essentially eliminate BH. 90-95% mortality from pneumonia iirc. So in areas used by domestic sheep, regardless of habitat, few if any BH will roam. It’s something wildlife agencies and a number of groups are very aware of and do work at.

With that large of mortality rate, and proximity to domestic sheep throughout the west, the prognosis doesn't seem good.

With those die-offs and sheep not allowed to roam into domestic sheep areas, it makes me wonder if learned migration routes have been forgotten with many herds. It seems like some of the mule deer migration data is showing that those routes are all forgotten once blocked.

 

[S-3 ranch]

I can’t speak for more northern latitudes but here in Texas & Mexico domestic and invasive species sheep are or have decimated wild sheep population
and are still being repressed by the flourishing population of aoudad

 

[MtnHunter]

I’m not sure and I’m not going to pretend to know. But I do know that some animals are just more tenacious to thriving. Think about animals extending their non historic ranges or animals introduced. Coyotes crossing the Mississip or coming to Alaska. English starlings. Himalayan blackberries or kudzu. And i have definitely noticed the expansions of whitetails and have witnessed two whitetail does bullying a family group of mule deer doesff of green feed.

Some of the proposed figures for wildness pre Colonial expansion I have a hard time buying and so by extension I have a hard time believing any of them for the same reason. They say there are more whitetail and more trees than before Columbus. How do they know?

Elk can be very dominant. I know mule deer suffer as elk populations get bigger. Maybe it’s the same for sheep. Maybe elk are just a heartier animal. But sheep everywhere are having a hard time in North America. If a fellow believed in any form of evolution, maybe he could rationalize the theory that maybe sheep are just going away on their own.

On a side note; I have done quite a bit of reading on the Lewis and Clark explorations and I cannot recall ever reading about moose. The country crossed is Shira‘s moose country, but Meriweather , a careful naturalist, never makes mention of them and I don’t think he preserved and shipped a specimen back to Washington, like he did with so many other animals, birds, fish and plants. He does say that the sheep were not as numerous as antelope and elk, which was also a plains animal.

Good point about some animals being more tenacious. I think I read somewhere that bighorns birth rate is a little lower than other animals like elk and deer as well. That whitetail/mule deer issue seems to be becoming more prevalent as well from what I hear. One thing that seems to remain constant is that everything is changing. I guess I'll appreciate the bighorns that are around a little more now!

 

[MtnHunter]

I can’t speak for more northern latitudes but here in Texas & Mexico domestic and invasive species sheep are or have decimated wild sheep population
and are still being repressed by the flourishing population of aoudad

That's interesting about aoudad. I hadn't considered that, but makes sense. Aoudad must be more of a tenacious animal like @LoggerDan mentioned.

 

[MattB]

Are domestic sheep known to be the only culprit? Or is it all or other livestock as well?

Feral goats are believed to be an issue as well.

And not only does the disease cause a high rate of death as mentioned above, but my understand is that the reproductive rate of survivors is low.

 

[WCB]

On a side note; I have done quite a bit of reading on the Lewis and Clark explorations and I cannot recall ever reading about moose. The country crossed is Shira‘s moose country, but Meriweather , a careful naturalist, never makes mention of them and I don’t think he preserved and shipped a specimen back to Washington, like he did with so many other animals, birds, fish and plants. He does say that the sheep were not as numerous as antelope and elk, which With that large of mortality rate, and proximity to domestic sheep throughout the west, the prognosis doesn't seem good.

Only one mentioning of Moose show up in their journey. Someone in their party wounded a moose. Can't remember who or when time frame wise but I believe it was along the Blackfoot River. Other than that nothing.

With that large of mortality rate, and proximity to domestic sheep throughout the west, the prognosis doesn't seem good.

Good friend of mine did field work on Bighorns in MT. We counted sheep and took note of any coughing etc. Luckily we saw none in two different herds of a about 20-25 sheep. Big problem was in those herds the animals were fairly local and did not migrate. However, the rams that came in during the rut came from 20-30miles away from each direction. She has a bunch of pictures of those Rams summering up high in other ranges and then showing up in that herd. So essentially even if a herd is say 20+ miles from a domestic herd they can get got.

 

[dapesche]

I recommend watching this movie.

It goes in deep on MOVI.

Let's you know what we're up to in BC thanks to WSF and WSSBC $$.

Sent from my SM-S901W using Tapatalk

 

[Billy Goat]

I have wondered for a while now how much elk pushing into the mountains have pushed the sheep higher up.

Maybe it hasn't effected them at all, but I suspect they use to sit further down in a lot of range that elk now occupy.

Haven't researched it, hasn't been that high of a priority.

 

[MtnHunter]

I have wondered for a while now how much elk pushing into the mountains have pushed the sheep higher up.

Maybe it hasn't effected them at all, but I suspect they use to sit further down in a lot of range that elk now occupy.

Haven't researched it, hasn't been that high of a priority.

I agree that something seems to have pushed many of them up high. Or maybe they've always been up high and the rest of their habitat at other elevations has become unusable. For example with that canyon I was talking about in the original post - that's not high elevation at all, but they only use the portion of the canyon that doesn't have domestic sheep grazing in and all around it. Or more likely, some people that understand M Ovi have worked hard to keep them separated at those elevations.

In my Googling, I also found this article about bighorns around Vail, Colorado. https://www.hcn.org/articles/landli...tt-heads-with-vail-resorts-affordable-housing This article talks about the bighorn wintering ranges at lower elevations have been crunched by development. In the summer it seems like they can go up high and have tons of habitat, but in the winter where the snow comes and goes on these south facing aspects like this article talks about, it seems like more houses decrease habitat. This almost makes me think the current carrying capacity is dictated by the amount of suitable winter habitat that is available and away from human development, domestic sheep, etc.

No doubt sheep and elk share habitat, as well as mule deer. In my own mind, based off what I've been reading and have learned about elk and deer, they all can eat the same things and cross over into the same habitat. That said, around here, it seems the deer prefer woody browse in all topographies, elk prefer forbs in all topographies, and bighorns prefer grass and sedges in cliffy topographies. If this idea holds up biologically, I'd think all three of these animals would complement each other on the landscapes.

The more I dive into this, the more complicated the issue becomes - which makes sense as to why sheep continue to struggle.

 

[tater]

Movi is an issue, and for the BC Cali populations Blue Tongue has been an issue in the last couple of years as well. We lost approximately 100 animals a couple of years ago in our region to BT.

BC has changed rules around use of camelids and goats as pack animals in certain regions to curb the potential transmissions of Movi.

As LoggerDan pointed out, there has always been and will always be shifts in species based on carrying capacities and habitat changes.

Geist predicted the extinction of Mule Deer caused by Whitetailed deer thirty years ago but paradoxically Whitetails carry a brain fluke that is not harmful to them, but kills moose. It is theorized that this is because there has not been a long period of historical range overlap for these animals in many locations.

Moose have thrived in areas that they never were (see South Central Saskatchewan) and have displaced deer.
Our Southern Cali Bighorn herd has had a huge impact on Mule Deer wintering grounds.
Even wild turkeys, so beloved by some hunters have a huge impact on biospheres when they are introduced. We are starting to get more data here in BC that suggests that the wild turkey transplant has been "too successful", and that is why there are more and more liberal seasons in some regions.

It's a big complicated piece of fabric: tug on one string at one end and there is a potential for unravelling at another end.

 

[tater]

So these are two of four young rams that have taken up residence at the bottom of my property. They will be around for another month to six weeks and then move back onto the early winter range as rut begins to swing.
They are now prime candidates for contracting Movi, as there are four sheep farms within 5km (two of which they are likely to move through enroute to the wintering range) and none of the farms are part of the screening program done by WSSBC.

 

[MtnHunter]

So these are two of four young rams that have taken up residence at the bottom of my property. They will be around for another month to six weeks and then move back onto the early winter range as rut begins to swing.
They are now prime candidates for contracting Movi, as there are four sheep farms within 5km (two of which they are likely to move through enroute to the wintering range) and none of the farms are part of the screening program done by WSSBC.

That's tough to learn about, and must be frustrating to you knowing they have hard odds to make it through the winter. Do you think you'd be able to tell individuals if they were to make it back your way next summer?

 

[tater]

That's tough to learn about, and must be frustrating to you knowing they have hard odds to make it through the winter. Do you think you'd be able to tell individuals if they were to make it back your way next summer?

Yeah, these four rams moved out the main area last year with a mature ram (nine year old) leading them. I'll be able to tell who is who when they return next summer.

If they don't get exposed to Movi or Bluetongue they only have to dodge the plentiful cougars and the odd wolf so survival is actually pretty high. As far as a "sheep's life" these ones have it pretty easy compared to a lot of other areas.

 

[2cow]

For whatever reason all sheep, wild and domestic, are very susceptible to pneumonia. Survival rate is low compared to other species even when treated with antibiotics. The causes of pneumonia in bighorns range from M ovi, to a lung worm, and many others. Sheep producers curb the risk with vaccines and mineral programs. It has been argued that these methods could also help the bighorns. The mineral is simpler to achieve by dispersing mineral blocks in areas where high risk bighorn herds frequent. However the vaccines are tougher as the wide arrange of causes require so many different types of vaccines. Also many have not been developed into an oral form. These also raise the question and argument of not being natural and producing a potential dependancy on these programs. Another factor is the shere number of predators that pick on sheep. Everything from eagles, coyotes, wolves, bears, mountain lions and of course humans. They all like lambchops and mutton. Many studies and programs have been done and are also ongoing, but.... most results and answers are dictaded by bias and monetary prejudices from all sides.