Wolf predation in the summer: Yellowstone Park study

In the latest “wolf weekly” report from Ed Bangs at USFWS, Ed wrote: Yellowstone Park researchers report that the summer predation study is going well. Approx 31 kills have been found May-mid through mid-July and they are 20 bulls, 5 cows, 5 calves, 1 mule deer. These data support the results of research done by following tagged elk calves [wolves killed few] and generally, but less so, scat analyses (scat analyses show more mule deer used in summer). Collar locations decrease from one every 30 min now to 8/day starting Aug. 1.

– – – –

I should say a bit more about this study. It is very important because all the quantitative data on wolf prey comes from winter observations when wolves generally have more of an advantage, and the ungulate composition in the Park differs somewhat from the summer when a lot of mule deer enter the Park from the Gardiner and some other areas.

Observation of summer predation is much more difficult than winter when the wolves are more easily seen and are more concentrated in the valleys.

In order to study summer predation, sophisticated GPS collars have been deployed on wolves. These collars give the wolf’s position at programmable intervals. It has been every 30 minutes during the early summer.

This allows location of the wolf and probably part of its pack even while in thick vegetation. Those helping with the experiment then hike to areas where the data indicate a probable kill and record the species, sex and any other data available. The results of this summer so far is what Bangs reported above.

While this data could be very accurate, the observations are yet so few, even with last summer’s data, to draw hard generalizations. Moreover, because just one wolf is presently collared, its pack may utilize different prey and at different rates than adjacent packs.

It may take a long time to establish firm generalization unless more radio collars are deployed and more people in the field. Dr. Douglas Smith told me he had been doing a great amount of hiking. Those of us who know how hot it has been on the northern range this summer can appreciate the physical effort this research must require.

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  1. elkhunter Avatar

    20 bulls? I thought wolves only killed the easy ones? thats what I have been told at least. 4 times as many bulls as cows. Interesting. Maybe that could be why not very many mature bulls in ID.

  2. Bob Ostler Avatar
    Bob Ostler

    Wolves are not trophy hunters. They kill the easy and the unlucky. Quite often this is the old, infirm, exhausted and very young, but not always.

    If you ever visit a feeding ground notice how few mature bulls there are mixed in with the herd (even in states with no wolves). I assumed the bulls were just skittish and stayed in the timber rather than wintering in the meadows, but when I asked I was told that this isn’t the case. Big bulls get shot in disproportionate numbers by hunters and poachers. The idea that we can eat our cake and still have it is very American, but flies in the face of reality.

    Wolves are not vegetarians, but we humans take far more total elk and far more adult bulls than wolves. I personally have no problem with this fact.

  3. Ralph Maughan Avatar

    As I tried to explain, these data are based on one radio collar, and so one shouldn’t place a lot of weight on the proportions until more data is in, but it is true that wolves often kill disproportionate numbers of one sex or age class, except prime adult elk that are well nourished and uninjured.

    In the winter predation studies, the data from each winter was quite variable.

  4. Jay Avatar

    So why are there so many bulls in Yellowstone elkhunter? If you’ve ever spent any time in the Park, you’ll find it’s crawling with them…not to mention that you’ll literally trip over shed antlers when hiking.

  5. Dan Stebbins Avatar

    These findings are interesting since, as Ralph mentioned, the vast majority of data taken by the Yellowstone Wolf Project has been from the Winter season. However from my time tracking with the wolf project, this does make sense to me. Especially in Springtime, Bull elk statistically are the most vulnerable portion of the elk population in the park.
    During mid-May and mid-June, the newborn Calves are within the first month or two of life. They are generally very tough for wolves to find, since they have no smell and are well-concealed in hiding places by the cow. So you then must look at the differences between the Bulls and Cows, both of whom are just recovering their strength from the winter. The biggest difference between the two, is that the Bulls go through a very stressful and physically demanding period (the rut), just before the snow sets in. So they therefore go into winter with their energy & fat reserves lower or more depleted than any of the cows. So it makes sense that they are at their most vulnerable in Late Winter and Spring, and therefore would make up a large percentage of wolf kills at this time.

  6. elkhunter Avatar

    Jay, I thought that the park collected the antlers and cut them up, plus its illegal to pick them up, so I could understand why there are so many. And of course its common sense if there has not been any hunting at all in Yellowstone for 50 years, that there just might be some big bulls. But I am willing to bet that we have bigger bulls in UT than in Yellowstone. Considering the fact that they found the horns of a bull that if he would of been killed in 2005 he would of been the WORLD RECORD, but they killed him in 2006 and he ended up scoring a measley #4 in the WORLD. And the biggest 6×6 EVER. So maybe we are doing something right in UT. So to counter that we should bring hundreds of wolves in to help out the struggling and very weak ecosystem that the elk here in UT are having to live with. I was just asking if wolves only target the weak and sick, why 20 bulls to 5 cows? even a weak bull poses alot more of a threat to injury than a healthy cow. Does it not? Bob I see HUGE bulls on wintering range all the time. And Jay not only in UT where we manage for big bulls. NM gives out lots of tags every year, a helluva lot more than UT does. Yet they produce 400 bulls all the time. And I see pictures of them on the winter range. Same with AZ. And also CO. In fact CO kills over 45,000 bulls every year. 45,000 BULLS. Yet they produce bigger bulls than ID. You should take a couple thousand wolves over there to stop that from happening. Then all the money that you raise from people looking at wolves, can be used to support all the management of the state game agencies. If you want Jay I can send you the data from those other states so you can compare.

  7. Ralph Maughan Avatar

    Elkhunter why would you say “even a weak bull poses more of a threat to a wolf than healthy cow?”

  8. elkhunter Avatar

    Even a 2-3 year old bull will be a couple hundred pounds larger, also the horns of a bull would pose a huge threat I would imagine, I watch elk in the Rut tear trees down, I can only imagine if it was a 100lb wolf.

  9. Ralph Maughan Avatar

    This is true, but consider that during late spring and early summer a bull’s antlers are in velvet.

    The primary way elk defend themselves, from my experience and from talking and reading, is with a kick. A forward elk kick with the front legs is like a punch, and it can put a hole in the chest of a wolf or other animal.

    After the rut the big bulls that engaged in major competition are often injured and exhausted.

  10. elkhunter Avatar

    Thats probably true also. In Yellowstone when is the best time to go and look at wolves? And is it easy to find them? My wife and I might go on a little road trip and Yellowstone was on the agenda, have not been there in a very long time.

  11. Dan Stebbins Avatar

    From my experience, the best time to see wolves in Yellowstone is winter. Driving along the northern range from Mammoth to Cooke City is your best bet. They are at lower elevations in the park and closer to the road. Spring & early summer is also pretty good because they localize around den sites. The toughest months to see them seem to be late July through parts of September. The elk and deer are at higher elevations looking for greener vegetation and of course the wolves follow them. Besides, if you & your wife are thinking relaxing road trip, then trust me you’re going to want to skip the Park traffic during those months anyway!

    As for seeing them luck always helps, but if you get up early and know where they have tended to be then it’s not terribly hard. The Hayden pack near Canyon has been the most visible recently, and actually the wolf packs in the northern range have tended to be less visible over the past few years. Ask the folks at the visitor centers and if you see a group of people parked looking out at something, stop and talk to them. Oh and generally folks see them from a good distance so if you’ve got a spotting scope or good binoculars definitely bring them.

  12. JEFF E Avatar
    JEFF E

    elk hunter
    according to Colorado’s fish and game statistics for 2006 the total harvest was 26,827 BULLS, 27,399 cows, and 2,707 calves for about a 24% over all success rate. As that is, lets say, significantly less than 45, 000 bulls. Could you tell me what I’m missing here?

  13. elkhunter Avatar

    I read the combined line. How many bulls were killed in ID? I know that the elk herd in ID numbers around 120,000. So how many bulls were killed in ID?

  14. elkhunter Avatar

    My point bein Jeff E. In that one study the wolves killed 4x as many bulls as cows. Now I know that was on study, but even if that is wrong, and lets say its only 2x the amount. Maybe thats why everyone complains about the quality of bulls in ID. Now I know that you believe with all your heart that the wolves in no way shape or form hurt the elk. Do you think that might be a contributing factor to the large amount of immature bulls in ID?

  15. Jay Avatar

    Elkhunter, in a round-about way, you make my point for me. You are correct, you can’t collect antlers in the park…in other words, no antler hunting = lots of antlers laying about. Just as no human bull harvest means lots of bulls in the park. I’m not going so far as to say wolves don’t have an impact on prey, but you seem to disregard the impacts long-term heavy harvest of bulls by people has on elk populations. I’ve said this over and over: Idaho has lots of hunting opportunity with general seasons, and as a result bull ratios (and primarily mature bulls) suffer. And I have no doubt Utah and New Mexico produces some fine bulls, but my argument wasn’t so much quality as quantity. Yellowstone has a bunch of mature bulls in the presence of lots of wolves. Quality is decided a great deal by habitat, which while I don’t have quantitative data, I would surmise to say Idaho is inferior to the other states you mention due to drier conditions, less alpine habitat, less productive soils, more forest habitat that has become overgrown, etc. Quite simply, Colorado can kill lots of elk because they have more than any other western state, and they have outstanding habitat.

  16. Jay Avatar

    Elkhunter, forgot to mention that even though you can’t collect antlers in the Park, you can still hike around and find some fine sheds to admire and leave for the next hiker. The Park rangers do destroy some sheds found near trails (I’ve come across several with saw marks), but they don’t find the ones away from trails.

  17. JEFF E Avatar
    JEFF E

    it also looks like more cows were killed in Colorado than Bulls. I guess that would mean there were 27,000+ non-hunters in Colorado hey elkhunter.

  18. elkhunter Avatar

    Ya, they kill lots of cows, and they have lots of elk, and lots of hunters, yet still have mature bulls. Kinda crazy huh. Add a couple thousand wolves, cause CO is big so they would need thousands not hundreds I would imagine.
    Jay, you have some valid points, but even in area 76A and 66A they have unlimited archery hunting and limited rifle hunting. And its considered the 2nd best unit in ID, second only to Unit 40. And both units are in the lower half of the state. I agree with you, different states have different habitats etc, now CO could probably handle some wolves without any difficulty, like you said in ID, elk face more difficult habitat, drier country etc, so would it make sense then that you might limit the pressure that wolves put on elk in certain areas. Like I have said before, I dont care if there are wolves, I think it would be cool to see one, I just dont follow into this line of thinking that wolves are what make the eco-system tick. And should be allowed to populate to as many as can survive in an area. Do you feel that wolves should be allowed to populate and spread as much as they want without taking anything into consideration? Just curious, cause we have objectives for deer/elk and moose, and every other animal. What makes the wolf exempt?

  19. Jay Avatar

    I’ve never been one to put wolves on a pedestal that should be considered untouchable…we hunt everything else, so wolves should be managed in balance with everything else, including people. Which also means I think we can make a few concessions and give wolves a piece of the pie, rather than a scrap of crust.

    Not sure what your point is on units 76 and 66 a’s. My interpretation is you’re saying those are good hunting units because they’re without wolves. Am I reading you right?

  20. JEFF E Avatar
    JEFF E

    elk hunter
    Idaho 2006 stats do not appear to be released yet, at least I can’t find them, so to compare apples to apples; in 2005 Colorado had an estimated elk population 300,000 with 23,817 bulls harvested. Idaho had an estimated population of 105,000 with 11,144 bulls harvested. So with a 3to1 difference in population Colorado only had a little more than twice the bulls harvested. That is interesting. Also interesting is the fact that Colorado is desperately trying to reduce the overall population by about 100,000 thousand animals. Sounds like they need a good old fashioned Rocky Mountain winter, or maybe a healthy predator population.

  21. elkhunter Avatar

    Jay, I agree with you, like I said I dont care if there are wolves. I just dont agree with THOUSANDS of wolves, and managing our big-game popuations for the sole purpose of having wolf packs. But I agree with what your saying. I just get bugged when people act as if wolves effect elk in no way. And those units do not have documented wolf packs.
    Jeff E, MATURE bulls Jeff. Not elk. I know how many elk are in each state. I feel that its important to have mature animals in a herd. I could be wrong if I am let me know. I am just saying this study of 4x as many bulls vs. cows being taken by wolves might have something to say as to why ID does not produce MATURE bulls. I know hunting has something to do with it. But do you feel wolves might have something to do with it also?

  22. JEFF E Avatar
    JEFF E

    elk hunter,
    that is exactly why your argument is so ridiculous. Idaho and Colorado and I believe Montana all have a verity of seasons for different classes/sexes of animals. Idaho is currently at or near objective for all classes of animals across the state including MATURE Bulls(go ahead and drool here). That is/has been determined by the state Fish and Game Dept. that is decidedly anti-wolf. If the only season was for MATURE(go ahead and drool here) Bulls then this would not be Idaho it would be, well, Utah and that would be indeed a sad day.

  23. elkhunter Avatar

    So let met get this right!!! Having MATURE BULLS WOULD BE A SAD DAY!!! You make me smile. I have never heard anyone say “We are at objective for Mature bulls”. Jeff E you are truly one of a kind. And we dont have only mature bulls. So by having MATURE BULLS it proves what? You have a healthy herd? You have big strong bulls passing on genes? You have high calf to cow ratios because breeding is done early in the rut? You have a game agency that is not struggling financially. You have big-game populations that people actually have a chance to kill something besides a raghorn or a cow!!!! But if I am reading you right, having elk herds with very few MATURE BULLS and yes Jeff E I mean MATURE BULLS, benefits ID and elk populations in what way? Yes Jeff E. your right, how UT would love to be like ID. You guys have nothing but a soap opera up there. Non-stop bullshit with the wolves, wasting everyones time and money, and to top it all off, you gotta shoot a cow/spike/raghorn/2-point. Where do I sign for that hunt? And people wonder why IDFG is struggling.

  24. Jay Avatar

    IDFG isn’t struggling because of lack of sales–non-resident elk and deer tags have sold out for the last several years, and in-state sales are what they’ve always been–it’s the increasing cost of doing business (fuel, inflation wage increases, etc.).

  25. elkhunter Avatar

    And Jeff E, you can get cow tags and spike tags here in UT. Also there are about 5 open bull units you can get tags on also. They sale thousands of them. One other thing, if you think UT only manages for HUGE bulls, they want the average age class to be 6 years old. Thats it. 6 years. So if it takes 6 years for a bull to be somewhat mature, imagine in ID, how young the bulls are. What would guess Jeff? 2-3? Maybe a couple 4 year olds. Ya I know they kill alot of elk in ID, but so does CO, and so does NM yet in some wierd way they are able to produce mature bulls, all the while offering lots of tags and opportunity. Why would you think that is? Just curious to your response.

  26. elkhunter Avatar

    Jay, there are lots of factors, they need to institute a point system, it would encourage people to put in, also raise revenue without issuing tags, and increase the quality of the hunts.

  27. JEFF E Avatar
    JEFF E

    elk hunter,
    we had this conversation before, Idaho received ~two million more money in 2006 from the sale of non-resident licence and tag fees than in 2005 an that increases yearly. Resident tags and licence fees are only cheaper in Montana. If it is is so bad here why will you be hunting here this year?

  28. elkhunter Avatar

    something new

  29. JEFF E Avatar
    JEFF E

    elk hunter,
    read what I post twice, more if necessary. Having MATURE(go ahead and drool here) Bulls would not be a sad day, Idaho has mature bulls. Modeling our hunting laws after Utah, or any other State would be.

  30. elkhunter Avatar

    Well if IDFG is struggling, and other states are not, it does not take a rocket scientist to do the simple math.

  31. elkhunter Avatar

    and if wolves get de-listed, then they are gonna have to come up with the funds to manage teh wolves. and thats not gonna be cheap I bet.

  32. Robert Wharff Avatar
    Robert Wharff

    The reason that Idaho has been hitting their non-resident cap has more to do with a recent law change that allows residents to purchase a second, leftover non-resident license.

  33. wolf gal Avatar
    wolf gal

    When a visitor asks where they can see a bull elk in the park I usually send them to the Blacktail Plateau area, which happens to be the territory of the wolf with the GPS collar. One wonders how much that plays into the results? Maybe a lot, maybe a little. I guess we won’t know until other packs with GPS collars are incorporated into the study.

  34. Layton Avatar

    Jeff E. says—–

    ” Idaho is currently at or near objective for all classes of animals across the state including MATURE Bulls(go ahead and drool here). That is/has been determined by the state Fish and Game Dept. that is decidedly anti-wolf.”

    Seems to me you and I had a discussion about this not to long ago — as I remember it (and I still have the printed reports) that isn’t necessarily true.

    There ARE SOME units that are meeting objectives — there are also some that ARE NOT — and wolves are mentioned in several areas as being a problem — either now or potentially in the Fish and Game reports that were the subject of that discussion. Also, maybe you should consider that the objectives in some areas have been changed — the numbers have been REDUCED. (could that have anything to do with Canis Puppydog?)

    Am I mistaken Jeff?? Or wasn’t it you that I was discussing that with??

    By the way, FWIW, there was a pack around Fairfield, Idaho taken out because of livestock losses and there was an article in McCall’s local paper this week detailing the increased depradation on the sheep in that area — even WITH more guard dogs and herders with rifles. But of course wolves don’t cause damage, they just “restore the balance” , right??


  35. Ralph Maughan Avatar


    I won’t comment on objectives, but you have read about all the fires just to the east of McCall? — hundreds of thousands of acres burned or burning.

    Many sheep and cattle have been moved into new areas, elk and deer have moved into new areas, and, of course, so have those animals that might eat them.

    At the present time, things are not quite normal in the area.

    – – – –

    A related question for someone, how much roast beef, lamb and mutton, did the Murphy fires produce?

  36. layton Avatar


    Right now I’m working on the fires East (and West and North and South) of McCall. You’re right — nothing is even close to normal.

    It’s still a real mess and shows no signs of even slowing down much — come on snow!!!


  37. JEFF E Avatar
    JEFF E

    I would suggest that you do what you recommend; read this report slowly for comprehension, and try to remember that each word and sentence has meaning.———–but I have come to believe that you are incapable of of doing that. I would therefore humbly recommend some remedial English classes through your local elementary school.

  38. Layton Avatar


    Once again (as has become normal) you can’t support your feeble arguments with facts — Note: facts, NOT just normal, “I love wolves” rhetoric — so you come with insults to people that you know nothing about.

    You know NOTHING about my education, IQ, reading preferences or even what kind of beer I drink!! (of course I’m sure that you can give some sort of a dissertation on the finer points of a small vintner’s Chablis – beer is soooooo mundane)

    Why don’t you pull your head out, try to tell the TRUTH once in awhile and knock off it infantile BS??

    The report you cited in our previous discussion did NOT indicate that ” Idaho is currently at or near objective for all classes of animals across the state including MATURE Bulls(go ahead and drool here). That is/has been determined by the state Fish and Game Dept. that is decidedly anti-wolf.”
    as you said. It showed several areas that were BELOW objectives and also showed that growing wolf populations were a concern.

    Your philosophy of repeating something – even if it is not true – over and over, ad nauseum is getting old.


  39. JEFF E Avatar
    JEFF E

    Ref. W-170-R-30
    I assume this is the same report you thought you read. If not, have some one show you the section titled “STATEWIDE SUMMARY”
    start on page 3; paragraph 2 and try to follow along,
    “Overall elk populations statewide are near all time highs. (eleven years after the big bad wolf was introduced). Elk numbers throughout northern, eastern, southern, and much of western Idaho have continued to increase over time.(ibid.)
    NUMMERICLY, THE STATE IS AT OR NEAR OBJECTIVE FOR TOTAL COWS, TOTAL BULLS, AND TOTAL ADULT BULLS.(emphases mine). (Gee Layton, this sound like the state is at or near objectives for all classes of animals), (assuming you equate mature and adult, yourself notwithstanding).However individual zone objectives reflect the need for a distributional change in in elk populations.”
    Care to go on with this, ace?
    No, I don’t know your education, but it appears minimal.
    As far as IQ each and every one of your posts continue to clear that question up.
    As to your beer preferences, who cares, but maybe you might want to abstain when you attempt to read a report such as cited above that has terminology in simple English.

  40. Layton Avatar


    As much as I hate to, I’d like to quote something that YOU said earlier ” read this report slowly for comprehension, and try to remember that each word and sentence has meaning” Do you remember that? I know it’s been a long time, but try hard.

    Now, read past the part where they say “summary”, there really is more to the report than that.

    Look carefully at some of the different zone reports, I won’t try to show you anything specific here, you don’t like to read things that I point out.

    Notice what some of the SPECIFIC ZONE reports say — can you comprehend the words??

    Now — get off of your high horse, try to use a little bit of common sense — instead of just trying to impress your fellow “wolfies” here on the blog — there, that wasn’t to hard, was it!! See, all the information wasn’t in the summary!! By the way Jeff, that’s why they are called “summaries”, they don’t have all the information!!!

    While we’re here Mr. education, when you try to quote something, maybe you should use cut and paste if you can’t type what you want to reference correctly — “NUMMERICLY” is spelled a bit differently than you did it here. “(emphases mine)” Could also use a bit of help. But of course you knew that, right?

    Ergo, ibid, out, you bore me.


  41. JEFF E Avatar
    JEFF E

    Okay, I’ll start to use spell check just for you. But tell me again how this report does NOT indicate that the state is at or near objective……… I’ve not had a good laugh yet today.

  42. JEFF E Avatar
    JEFF E

    YOU’ER RIGHT. A Summary does not contain all information contained in the related paper. According to the American Heritage Dictionary, a summary is ” a presentation of the substance of a body of material in a condensed form or by reducing it to its main points….”. An example of that would be the statement ” numerically the state is at or near objective for total cows, total bulls, and total adult bulls”. That would be a MAIN POINT of the report that you are having trouble understanding.


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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