Yellowstone Park: Northern range packs are all large. Winter may be interesting

As autumn begins, for the first time not only are all of the packs on the Yellowstone Park northern range large, they are all almost equal in size.

The Park pup count for the year is quite accurate and pup survival was high, but it is harder keep track of the adults, so with the possibility of being off 2 or 3, basically the situation is this: Druid Peak 20 wolves, Agate Creek 20 wolves, Oxbow Creek 20 wolves, Leopold 20 wolves, Slough Creek 20 wolves.

The Slough adults are all females except for one male born to the pack some time ago, and a brand new alpha male who came from the Agates. The previous Slough alpha, now decreased, had seized the opportunity to became the pack’s leading male while he was just a yearling because of the sex ratio imbalance. He killed about a month ago by a vehicle in the Park. He was quickly replaced by another yearling male from the nearby Agates. He is also uncollared and unnumbered. The older male in the Slough Creek pack is likely the son of the alpha female so that is why he has not advanced to alpha status. Field studies and especially genetic studies of Park wolves show they strongly avoid inbreeding. This was confirmed in the findings of the recently released ‘The genealogy and genetic viability of reintroduced Yellowstone grey wolves.” VonHoldt, et al. Molecular Ecology (2007).

To the south a bit, the Hayden Valley Pack remained visible to people all year with its 5 adults and 4 pups. Nine wolves is a substantial pack, but they have an overlapping territory with the larger Gibbon Park of 10-12 adults and 2-4 pups (good pup sightings were never made for this hard-to-see-pack). The Haydens are also in contention with the brawny bison-killing Mollies Pack (8-9 adults and 5 pups).

The Hayden Pack alpha pair have become about the most photographed wolves in the Park’s history. They are now both relatively old. In their territory they need to be able to kill bison to make it through the winter. In the summer there are elk plus a convenient carcass dump in the vicinity (for animals hit on the Park roads). I learned about the dump while wolf watching this summer from folks who had been following the pack.

Dr. Doug Smith told me that studies have shown that the ability for a wolf pack to kill bison is different than killing elk (where speed is an advantage, something more typical of female wolves). Successful bison-killing packs are like Mollies. They have a number of large, strong male wolves.

While I don’t have a run down on the rest of the Park’s packs, I want to mention the Bechler Pack because I had no information about them this year until today.

They continue to inhabit the SW corner of Yellowstone (Bechler Meadows), but they do sometimes leave that vicinity. Two weeks ago they were tracked near Lewis Lake. That’s interesting because an Idaho State University student trip to the backcountry in that area heard wolves howling. This is not usually a place you hear that.

The Bechler Pack has 10-12 adults and 4-5 pups.

The Park population is up for the second year in a row after the big crash, although the mid-year estimate of about 175 is probably an overestimate because the adult wolf count for mid-year was mostly based on that of late last winter.

Factoring in the Yellowstone Park wolf increase, we see that it accounts for much of the Wyoming increase at mid-year as reported by ED Bangs the other day.

Update: In one of the comments below Kathie Lynch adds detail to the 20-20-20-20-20 breakdown of the wolf packs on the northern range. She also adds detail about the Slough Creek Pack males and other Park wolves.




  1. Michael Avatar

    I was on a wolf watching trip in the Park with my wife during the period when the Slough Creek pack’s alpha male was killed by a vehicle. It occurred late in the evening of 9/11. As I understand it, this is first Yellowstone wolf to die in this manner since 2000. Within a couple of days, Agate 590M became the Slough’s new alpha male. These events caused a gray male with a nonfunctional collar to leave the pack. This wolf was known to be socially weak and was described by one ranger as immature. At 17 months, 590M has the distinction of being the youngest alpha male in the history of the Yellowstone Wolf Project. It is not known whether 590M drove the collared gray off or if the collared gray left on his own impetus. It was also not clear if the collared gray would rejoin the pack. He was not seen with the Sloughs again until the evening of 9/15 when he was observed contesting a carcuss with some grizzlies along with three other Slough adults. While this may have been a positive step in rejoining the pack, it did not demonstrate any kind of tolerable relationship between 590M and the collared gray. We left the park the next day on the edge of our seats and have not yet heard how all this turned out.

  2. Ralph Maughan Avatar

    Thank you for this important added information, Michael.

    I was hoping someone would give some info on the other male in the Slough Creek pack

  3. kim kaiser Avatar

    “As I understand it, this is first Yellowstone wolf to die in this manner since 2000. ”

    i beleive a Mollies wolf in hayden was killed earlier this year by a car.

  4. Kathie Lynch Avatar
    Kathie Lynch

    Here is a little bit more specific info, as far as I know…
    The Druids number 18 wolves (11 adults and 7 pups/9 black, 9 gray); the Sloughs have 21 (8 adults and 13 pups/17 black, 4 gray); the Agates have 19 (10 adults and 9 pups/6 black, 13 gray). I think the Oxbows have 19 total/17 gray, 2 black (not sure about adult vs. pup count).
    The beautiful dark gray collared male who departed the Sloughs after the brand new (former Agate) alpha male, 590M, arrived on Sept. 14, was not Slough 491M, as was previously thought. Slough 491M had been born in 2004 and dispersed in January, 2006. When a collared gray waltzed right in and joined the Sloughs in spring, 2007, he was thought to be 491M. However, his collar didn’t work and did not match the appearance of 491M’s collar, so there was a lot of confusion. Anyway, he is currently no longer with the Sloughs–but, of course, he may waltz right back in again in the future!
    The Hayden alphas are thought to be about seven years old, with 540F born in the Nez Perce pack and 541M perhaps born an Agate (Another alpha son of venerable Agate 113M? If so, 113M has alpha sons in the Agate, Slough and Hayden packs!)
    Finally, Mollie’s 497M was the wolf killed by a vehicle near LeHardy Rapids in the Hayden Valley in May, 2007.

  5. Vicki Avatar

    I am headed to Yellowstone in one week. I go every summer, but this will be my first fall trip. In the past 11 summers I have had some success, but not enough, viewing the wolves. I hear a loy about various landmarks. Any hints on how to find a map with them on it? Any suggestions about locations to try? (Where exactly is Little America?) I am going to try to spend one day in the Lamar area…near the Yellowstone Institute. I also want to go to the Hayden Valley, but don’t know the best area to park and scope. Any input would be great.

  6. Jim Avatar

    Vicki, try this link, it is to a forum dedicated to YNP. A person named Max (fiznatty) has started to map wildlife viewings by location. Try asking him where it is.

    Read the latest posts. Many regular visitors to the park post the what and where of what they saw.

  7. skyrim Avatar

    These links may be helpful to you. There is another map that describes the various locations and nic names of spots in the lamar area. I’m certain Ralph has it linked somewhere here but my time is limited this morning. The second link is a large map and accordingly the file is pretty big.

  8. Jim Avatar

    Vicki, this is the map that I was talking about. For more exact locations (i.e. Otter Creek, Dead Puppy Hill) and where they are read the posts on that forum. Also consider that wolf watchers are everywhere now so follow the scopes. Park Ranger Ric Mcintyre (sic) has a yellow SUV, if you see it parked somewhere he is looking at wolves.

  9. Vicki Avatar

    Thanks so much guys!!!! You have been amazing, and helped a ton. I will let you know what I see!

  10. Lynn Avatar

    Son was in the park this weekend hiking. They saw a black wolf with a yellow collar near Swan Lake above Mammoth. That wolf and two other blacks were on a carcass near the lake. Do you know what pack they belong too? Thank you!


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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Ralph Maughan