Effects of Wolf Mortality on Livestock Depredations

[Mark Billadeau]

Link is to full article.

 

Effects of Wolf Mortality on Livestock Depredations

 

Abstract

Predator control and sport hunting are often used to reduce predator populations and livestock depredations, – but the efficacy of lethal control has rarely been tested. We assessed the effects of wolf mortality on reducing livestock depredations in Idaho, Montana and Wyoming from 1987–2012 using a 25 year time series. The number of livestock depredated, livestock populations, wolf population estimates, number of breeding pairs, and wolves killed were calculated for the wolf-occupied area of each state for each year. The data were then analyzed using a negative binomial generalized linear model to test for the expected negative relationship between the number of livestock depredated in the current year and the number of wolves controlled the previous year. We found that the number of livestock depredated was positively associated with the number of livestock and the number of breeding pairs. However, we also found that the number of livestock depredated the following year was positively, not negatively, associated with the number of wolves killed the previous year. The odds of livestock depredations increased 4% for sheep and 5–6% for cattle with increased wolf control - up until wolf mortality exceeded the mean intrinsic growth rate of wolves at 25%. Possible reasons for the increased livestock depredations at ≤25% mortality may be compensatory increased breeding pairs and numbers of wolves following increased mortality. After mortality exceeded 25%, the total number of breeding pairs, wolves, and livestock depredations declined. However, mortality rates exceeding 25% are unsustainable over the long term. Lethal control of individual depredating wolves may sometimes necessary to stop depredations in the near-term, but we recommend that non-lethal alternatives also be considered.

[juliepoudrier]

The abstract is intriguing. I will read the full article as soon as I get a chance.

 

Thanks Mark.

 

J.

[GentleLake]

I read about this yesterday.

 

Look how the idiot wolf haters are responding to it: http://www.nbcnews.com/science/environment/kill-wolf-more-sheep-will-die-study-suggests-n260826

[Sue R]

I agree, most interesting.

 

What's the best answer for livestock producers? Guardian dogs where feasible, I think.

[juliepoudrier]

Gotta love this quote (from Roxanne's link above):

 

 

"The job of 'predator' in Washington is already filled by cougars, bears and coyotes. By adding a wolf to the mix, we are forcing predators to compete for a limited prey base and we know they will move on to domestic animals and possibly children as new sources of food."

 

Kill all the wolves because they're going to eat the children? Seriously? I'd be more worried about kids dying from things like drugs or shooters in schools, but apparently in Washington state the biggest threat to the life of a child is a wolf. Go figure.

 

J.

[GentleLake]

Pretty ludicrous, right? Especially since there's never been a documented case of a healthy wolf killing a human in the US (and IIRC in North America).

 

Talk about fear mongering. <sigh>

[Maxi]

i'm not doubting the authors' model based on the complete 25 year dataset, but if you look at the supplementary table 1 http://www.plosone.org/article/fetchSingleRepresentation.action?uri=info:doi/10.1371/journal.pone.0113505.s003 - there does seem to be some years ( eg 2009) that have a large number of sheep depredations. These combined with the early years in the study (upto ~1995) that has significantly fewer wolves may skew the dataset.

It would be interesting to see if the authors' conclusions still hold with these 'outlying' years removed.

Also the authors state in the methodology "Only the total numbers of livestock killed, not the number of confirmed livestock depredation incidents, were available from the USFW database." I'm uncertain what the authors are trying to say here because the abstract of another paper analysing wolf attacks on stock in Italy suggests that in that country there are false claims of predation submitted in order to obtain compensation. Is there a similar compensation scheme in the US?

BTW I agree with Others comments about the absurdity of some trying to raise public fear about potential wolf attacks on humans.

[GentleLake]

false claims of predation submitted in order to obtain compensation. Is there a similar compensation scheme in the US?

 

Yes, at least in some areas of the US, particularly in areas where wolves have been reintroduced, farmers and ranchers are compensated for at least predation by wolves.

 

I've heard accusations of false or unsubstantiated claims being made.

[Maxi]

 

Yes, at least in some areas of the US, particularly in areas where wolves have been reintroduced, farmers and ranchers are compensated for at least predation by wolves.

 

I've heard accusations of false or unsubstantiated claims being made.

Thanks, So I guess that means that some of the data that the authors used concerning the number of livestock predated may not be an accurate reflection of actual number predated by wolves (this is what I presume the authors themselves are trying to imply in the sentence I quoted in my earlier post).

[nancy]

I seem to remember hearing that we had to allow so much hunting of deer, elk, moose.... because there we no longer any natural predators to control the population. Now, I hear that reintroducing the natural predators reduces those populations so that hunters are not getting to kill enough trophy animals.

Duh? The only acceptable predators are humans?

[TEC]

In Washington State, where I live, I have not heard an inordinate fear of wolves preying on humans. Cougars, OTOH, are becoming an increasing problem, especially in the overlap areas of farms/ranches, forest and medium sized residential lots. They are being sighted on recreational trails. There may be a few scared people.

 

As to false claims to obtain compensation and accuracy of research data, my take on that is that claims by farmers/ranchers are often made based on limited evidence available, and information that wolf packs are known to be in the area. I have no first hand experience with the problem, but through reading local accounts, it appears to be almost impossible to prove to a high degree of certitude that any attack on livestock is from a particular predator. Scavenging by multiple species is known to occur soon after an animal is brought down. I do not want to believe that very many outright fraudulent claims are made, but of course a portion may be incorrect. The minimum allowable claim is $500. In Washington there is a litany of hoops to jump through, including protecting the carcass, and having it investigated by Washington Dept. of Fish and Wildlife (WDFW). I doubt that many incidents, legitimate or illegitimate, pass muster under the established standards for compensation. I would like to know whether the system works. -- TEC

 

ETA -- Link to Washington Gray Wolf Conservation and Management 2012 Annual Report, by Washington Dept. of Fish and Wildlife (WDFW). The report states (pg. 10) that for 2011-2012 wolves caused 17 injuries/mortalities, and for year 2012 $1595 was compensated to wool and cattle producers (pg. 12). Here is another link to Washington State's Wolf Conservation and Management 2013 Annual Report. It is very readable and in PowerPoint format. Great photos. See page 43. Therein it states that for 2013 there were 20 wolf-livestock depredation investigations. A mere 4 were confirmed wolf caused, and 6 were unknown causes. Page 53 appears to say that of a half million expended on wolves, year 2013, zero dollars were for compensation.

 

A boondoggle for Washington farmers/ranchers? I say no. To me, it would be speculative to say that all claims-made for suspected wolf depredation are reasonably exhaustive of all known and unknown incidents that occur. A lower monetary damage threshold (currently $500) would go toward more complete reporting and claims made.

 

Further, it is hard to evaluate the accuracy of WDFW's determination of whether depredation is wolf-caused. It could be sensibly argued that the State agency charged with increasing wolf numbers in order to accomplish State delisting (pg. 3) should not be the same agency that makes wolf-caused depredation determinations for compensation purposes.

[juliepoudrier]

I had always understood that farmers/ranchers are generally given the benefit of the doubt when it comes to predator kills. I could be wrong, and I don't have time to go research it right now. But because as Tom states above it's difficult to know what killed livestock, the Fish and Wildlife folks will usually err on the side of the rancher. After all, part of getting ranchers to agree to reintroduction was the assurance that they would be compensated for killed livestock.

 

J.

[Maxi]

I'm not criticising the ranchers for claiming compensation...but it only needs a small percentage to over claim in order to doubt the model and conclusions of the scientific paper that Mark linked to in post 1.

[DeltaBluez Tess]

We have had coyote and cougar kill our sheep and it was obvious.....one cougar prints and he buried the sheep with grass....the coyotes are the ones who kill the most and once the LGD got a hold of one and basically ripped him in half.....I have seen the coyotes stalk the sheep all the way up to the barn and get 20 feet from the barn.....

[emilyfalk]

Thanks for the link.

 

Not wolves, but here we have a coyote bounty. $40 a carcass with a county cap at $5000, and a winner is crowned at the end of the year. It was decided to keep the bounty lower than neighboring areas to dissuade hunters from bringing in outside carcasses. Our farmers mean business here.

[juliepoudrier]

I wonder about the coyote/wolf dynamic. Guess I need to research it. Does more wolves = fewer coyotes?

 

J.

[Maxi]

Also does anyone know what are the dynamics between avaibility of other prey ( e.g wild deer/elk/moose) or the severity of the weather conditions and the number of livestock attacks by wolves?

[Tommy Coyote]

TEC: My brother lives right down on the Spokane River. He used to fish at night on the river. No more. He's afraid of cougars. He hasn't ever seen one but you never know. He isn't willing to risk it.

 

One thing, tho. When I was growing up on the river we never saw deer or racoons. Now they are common. Increasing deer populations along the river could very well bring in the occasional cougar.

 

When I was little we saw lots of pheasants, quail, ducks, porcupines, squirrels and chipmunks. No deer. My brother sees deer all the time now.

[Tommy Coyote]

Julie: I know I read that the wolves in Yellowstone will not tolerate coyotes. The ecosystem there shifted after the wolves were introduced. The coyotes had lived off small game. The larger herbivores were destroying a lot of plant life in the park. The wolves drove the coyotes out (or at least the coyote population is smaller now) and they feed on the larger prey. The populations of the smaller animals are now much healthier. The trees aren't being eaten down by the larger herbivores. Actually, the whole ecosystem is a lot healthier.

 

I know GentleLake pointed out that there are wolf/coyote crosses that are really big coyotes. I don't know how common it is for wolves and coyotes to actually mate.

[GentleLake]

Coyotes originally were indigenous to the western half of North America. As habitat changed (forests cut down, creating more open spaces that coyotes prefer) and wolves were exterminated, coyotes moved in to fill the void left by declining wolf populations.

 

In much of their present day range they are -- like humans, rats, starlings, pigeons, and cane toads & rabbits in Australia, etc. -- a very successful invasive species.

[GentleLake]

I know GentleLake pointed out that there are wolf/coyote crosses that are really big coyotes. I don't know how common it is for wolves and coyotes to actually mate.

 

I don't think it's especially common. I think the hypothesis is that there may have been some interbreeding in eastern Canada when wolf populations were declining. But because behaviorally they haven't changed much, if at all, it's believed any wolf influence is minimal.

 

There are other explanations for larger coyotes in the Northeast, such as the phenomenon that animals tend to grow larger further north than their more southerly counterparts.

[TEC]

In much of their present day range they are -- like humans, rats, starlings, pigeons, and cane toads & rabbits in Australia, etc. -- a very successful invasive species.

An invasive species has a negative effect on the environment, economy and/or health. We humans certainly do our share of damage, but unlike other animals we have the ability to turn things around. I like to think that our injuries to earth are beginning to be counterbalanced by benefits bestowed and damage repaired, looking toward a net positive effect. For me it is a matter of seeing processes rather than static definitions, and more uplifting to the spirit.

 

Putting humans adjacent to rats may wake-up a certain mind-set. It is not the type of rhetoric that motivates me.

Here in the west, IMO, coyotes are seen as an annoyance by those who raise livestock, but manageable. Do they have a more negative impact in your part of the Country? -- Regards, TEC

[juliepoudrier]

In the more populated areas I think the biggest contributor to small livestock kills is roaming pet dogs, then coyotes. I was really just musing about whether wolves are responsible for more or less predation on livestock than coyotes. I'd guess it's the latter, though that may just be a population numbers thing.

 

It would be nice to see a study that compared losses to coyotes to losses to wolves. If ranchers are able to live with/deal with losses caused by coyotes, then why not with those caused by wolves? In general I would say coyotes are the more opportunistic species, and if you count your poultry, barn cats, etc., in the number then coyotes are likely to cause far more damage than wolves.

 

As for cougars, I'm sorry that their presence has cut into some human recreational activities, but I'm glad that some of the apex predators are actually making a comeback. Despite now even allowing hunting on Sundays, hunters can't seem to really control the deer population (for example). Maybe more natural predators could help, but we as a species would have to learn to tolerate those predators.

 

J.

[DeltaBluez Tess]

Loose dogs used to be an issue but the problem dog is "gone" now.

 

Coyotes are not an annoyance here as they are the main predators for my flock as well as my other friends flocks. I have a pack that lives a couple of blocks away and they are always looking for a free meal. With 2 LGD and a guardian Arab mare, we are ok but if a pasture is missing of the above, the coyotes will visit.

 

I have seen them lure the LGDs away with a couple of coyotes then ones will sneak up from the back to grab a lamb. I was ready with a gun so made that one rethink that. I would say that coyotes are the main predator of sheep around here.