Yellowstone National Park Yellowstone Center for Resources

Yellowstone Wolf Project 2019 National Park Service

Wyoming, Montana, Idaho Department of the Interior

Yellowstone Wolf Project

Annual Report

2019
Summary
There were at least 94 wolves in 8 packs (7 breeding pairs) living primarily in Yellowstone National Park (YNP) at the end of
December 2019. Overall, wolf numbers have been relatively stable from 2009 to 2018 (80-108 wolves.) After dropping to 80 in
2018, numbers rebounded this year with high adult survival and several packs producing multiple litters. Seven breeding pairs
(defined as an adult male and an adult female with at least two pups that survive through the end of the year) was the same as the
average over the last decade. Pack size in 2019 ranged from 4 to 19, averaging 11.5 in size. Parkwide, 61 pups were produced and
42 survived (68.9%) to year end, with more in northern Yellowstone (27) than the interior (15) of the park. At the end of 2019,
pups comprised 44.7% of the park population, higher than the average percentage (32.4%) over the last 10 years.

Wolf-Prey Relationships while searching 71 GPS wolf clusters for the Junction Butte
Project staff detected 186 kills that were definitely, probably, pack. Twenty-five (81.0%) of these ungulates were killed by
or possibly made by wolves in 2019: 111 elk (59.7%), 38 bison wolves, which included 16 (64.0%) elk, 7 (28.0%) bison, one
(20.4%), 11 mule deer (5.9%), 2 deer of unknown species (4.0%) deer, and one (4.0%) unknown species. Three of the
(1.1%), 3 coyotes (1.6%), 2 pronghorn (1.1%), 2 ravens (1.1%), elk (19.0%) were calves, four (25.0%) were adult females,
one red fox (0.5%), one moose (0.5%), one golden eagle six (38.0%) were adult males, two (13.0%) were adults of
(0.5%), one bald eagle (0.5%), one mountain lion (0.5%), one unknown sex, and one (6.0%) was of unknown age and sex.
domestic dog (0.5%), and 11 unidentified animals (5.9%). The The wolves also fed on four bison, one elk, and one deer that
domestic dog death was outside Yellowstone in a residential, they did not kill.
gateway community and occurred at night. The composition of
Summer Predation
wolf-killed elk was: 31.5% calves, 7.2% yearlings, 21.6% adult
We also assessed wolf predation from May through late July by
females, 23.4% adult males, 7.2% adults of unknown sex, and
searching for prey remains at clusters (a location other than a
9.0% of unknown sex and age. The composition of wolf-killed
home site where a wolf spent 30 minutes or more) generated
bison was: 42.1% calves, 21.1% adult females, 28.9% adult
from GPS collars. In 2019, we searched 147 clusters for wolf
males, and 7.9% of unknown sex and age. Wolf predation was
907F of the Junction Butte pack. Crews hiked over 1,263
monitored intensively for nearly five months of the year – one
kilometers (785 miles) to detect 41 suspected kills or fresh
month in early winter (mid-November to mid-December),
carcasses of ungulate prey, which included 26 (63.0%) elk, 13
one month in late winter (March), and several months in the
(32.0%) bison, and 2 (5.0%) unknown species.
summer (May-late July). The type of prey killed by wolves
varies by time period, but consists primarily of elk and bison. Mortalities
Only two radio-collared wolves died in 2019. After being
Winter Studies
injured by other wolves, the dominant male of 8 Mile, 962M,
During the March 2019 late winter study period, air, ground,
could not keep up with the rest of the pack and became a lone
and GPS cluster search teams discovered 69 ungulate carcasses
wolf. He traveled out of Yellowstone and was harvested in
fed on by wolves. The GPS cluster crew searched 176 GPS
Montana in January. Wolf 1118F’s GPS collar sent a mortality
clusters (locations in which a GPS-collared wolf spent ≥ 1hr)
signal in September 2019, indicating she had not moved for at
for two wolf packs (8 Mile and Junction Butte) through hiking
least four hours. We will attempt to recover the collar in summer
or skiing over 930 kilometers (580 miles). Fifty-one (74.0%) of
2020, but any remains will be scavenged or decomposed. In
these ungulates were killed by wolves, including 29 (57.0%)
addition, staff recorded five uncollared wolf deaths. Two
elk, 9 (18.0%) bison, 10 (20.0%) deer, one (2.0%) moose,
seven-month old pups from Junction Butte were hit by a
and 2 (4.0%) unknown species. Nine of the elk (31.0%) were
vehicle in late November. Both pups died immediately. Three
calves, three (10.0%) were yearlings, four (14.0%) were adult
wolves were harvested in state hunting seasons: two Phantom
females, nine (31.0%) were adult males, and four (14.0%) were
Lake pups in Montana, and one Mollie’s wolf in Wyoming.
adults of unknown sex. The wolves also fed on ten bison and
For the second year in a row we recorded no intraspecific-
eight elk that they did not kill.
caused mortality, which is usually the leading cause of natural
During the November-December 2019 early winter study mortality in the park. However, deaths of uncollared wolves
period, we discovered 31 ungulate carcasses fed on by wolves. from natural causes are rarely found and recorded.
The GPS cluster crew hiked over 747 kilometers (465 miles)

COVER: The Junction Butte pack takes time out to howl. NPS Photo - D. Stahler.

2 |Yellowstone Wolf Project Annual Report 2019

 2019 Yellowstone Wolf Pack Territories
(95% minimum convex polygons of aerial locations)

Yellowstone Wolf Project Annual Report 2019 | 3

Disease Wolf Capture
There was no evidence of any major disease mortality in 2019. Twenty-four wolves from six packs were captured and col-
The wolf density in northern Yellowstone is the highest it has lared in 2019. Six of these replaced old or malfunctioned
been in over 10 years (approximately 50-70 wolves/1000km2, transmitters. A number of measurements and biological
depending on movements of the Wapiti Lake and Mollie’s samples were also taken while the wolf was sedated. Twelve
packs), which may facilitate disease transmission over the females and twelve males were captured; three were old
next year. Ellen Brandell, a graduate student at Penn State, adults (≥6 years old), six were adults (2-5 years old), three
is investigating the prevalence and abundance of canine were yearlings, and twelve were pups. A female from the
parasites and has collected scat samples from most packs in Cougar Creek pack was collared and her genetic markers in-
northern Yellowstone. dicate she is actually 953F from Cougar Creek, whose collar
was chewed off in 2017.
Reproduction
Each year staff attempt to establish early pup counts at dens Wolf Management and Outreach
by either observing from the ground through spotting scopes Wolf management activities included den site closures
or, more often, taking photos of the den area during tracking and several hazing events. Staff continued to manage wolf
flights. Since wolf pups normally stay underground for their viewing areas in Slough Creek, Lamar Valley, and other areas
first three to five weeks, the earliest counts for each pack are where wolves were frequently observed. Wolf Project staff
often of two to three month old pups. For some packs whose observe wolves through spotting scopes and, during 2019, at
den sites are unknown or hidden, we do not get pup counts an average distance of 2.4 km. This distance facilitates data
until the pups are moved to a rendezvous site in the early collection on completely natural wolf behavior uninfluenced
fall. This year the Wolf Project documented at least 61 pups by human presence. In January, biological technician Jeremy
born to seven different packs. Four packs produced multiple SunderRaj spotted the Junction Butte pack from a distance of
litters: Junction Butte (17 pups from four litters), 8 Mile (11 11.4 km (over 7 miles) away! Hayden Valley, a common place
pups from two litters), Phantom Lake (at least 13 pups from to view wolves in the past, was rarely used by the Wapiti Lake
at least three litters), and Wapiti Lake (9 pups from two lit- pack in 2019. Public outreach included giving 119 formal
ters). Many of these packs, however, lost some pups by the talks (six at scientific conferences), 76 interviews, educating
end of the year and pup survival for those packs with mul- at least 10,000 people while viewing wolves, making at least
tiple litters was 64.0%. Of the minimum 61 pups produced 15,000 visitor contacts, and giving 158 informal talks in the
in all packs, 42 (68.9%) pups survived to the end of the year. field.

Wolves often travel single file when in snow - unless of course, you are a pup (first wolf in line and flanking white female.) Wapiti Lake pack in Hayden Valley
in late 2019. NPS photo - D. Smith.

4 |Yellowstone Wolf Project Annual Report 2019

 Yellowstone National Park Wolf Population
1995-2019
200

180

160

140
# of Wolves

120

100

80

60

40

20

0
1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019
Yellowstone National Park Northern Range Interior

2019 Wolf Population 2019 Wolf Capture

YELLOWSTONE WOLF POPULATION Date of
Adults Pups Total Wolf #/Sex Age Color Pack
(as of 12-31-2019) Capture
NORTHERN RANGE 1104F 2/19/2019 Yearling Black Wapiti Lake

8 Mile 9 8 17 1198F 2/19/2019 Pup Black Cougar Creek

1199F 2/19/2019 Pup Black Cougar Creek
Phantom Lake 4 7 11
1200M 2/19/2019 Adult Black Cougar Creek
Junction Butte 10 8 18 1201F 2/19/2019 Pup Black Wapiti Lake
Lamar Canyon (no collars) 3 4 7 1203F 2/21/2019 Yearling Gray Wapiti Lake

Other (1154F & 1200M) 2 2 1117M 2/22/2019 Adult Black Cougar Creek
1204F/953F 2/22/2019 Adult Gray Cougar Creek
Northern Range Totals 28 27 55
1047M 12/14/2019 Adult Black Junction Butte
NON-NORTHERN RANGE 1048M 12/14/2019 Adult Black Junction Butte
Bechler (no collars) 2 2 4 1228F 12/14/2019 Pup Gray Junction Butte
1229F 12/14/2019 Pup Black Junction Butte
Cougar Creek 6 6
907F 12/14/2019 Adult Gray Junction Butte
Mollie's 6 4 10
1230M 12/15/2019 Pup Black 8 Mile
Wapiti Lake 10 9 19 1231M 12/15/2019 Pup Gray 8 Mile
Non-Northern Range Totals 24 15 39 1232M 12/15/2019 Pup Black 8 Mile

YNP Total 52 42 94 1233M 12/15/2019 Pup Black 8 Mile

1234M 12/15/2019 Yearling Black Wapiti Lake
1235F 12/15/2019 Pup Black Wapiti Lake
1236M 12/15/2019 Pup Black Wapiti Lake
1005F 12/16/2019 Adult Black Phantom Lake
1237M 12/16/2019 Adult Gray Mollie's
1238M 12/16/2019 Pup Black Mollie's
1239F 12/16/2019 Adult Gray Mollie's

Yellowstone Wolf Project Annual Report 2019 | 5

2019 Wolf Mortality
Wolf #/Sex Date of Death Age Color Pack Cause of Death

962M 1/22/2019 Old adult Black Alone Harvest

Unknown, likely due to complications after being shot and

1118F 9/12/2019 Adult Gray Alone
injured in late 2018

uncollared 10/29/2019 Yearling Gray Mollie's Harvest

Junction
uncollared 11/19/2019 Pup Black Vehicle
Butte
Junction
uncollared 11/19/2019 Pup Black Vehicle
Butte
Phantom
uncollared 12/10/2019 Pup Gray Harvest
Lake
Phantom
uncollared 12/10/2019 Pup Gray Harvest
Lake

Wolf Project Leader Doug Smith was invited to give a TEDx

talk in Big Sky, MT, in January 2019. His talk examined human
perceptions of wildlife and our place in this shared world. It
was titled: “Should Humans Rule the World? Using Wolves
to Connect with Nature” and can be viewed on YouTube
(https://www.youtube.com/watch?v=kCu34aAyBFc). Doug
also gave formal presentations and interviews with BBC,
PBS, Yellowstone Public Radio, National Geographic, Science
Magazine, WY Public Radio, Men’s Journal, NOAA, The
Meateater, and many others.

Wolf Project Research Associate Kira Cassidy taught a three-

day field course through Yellowstone Forever called “Animal
Families: Lessons on Growing Up Wild.” The course took
place at the Lamar Valley Buffalo Ranch and will be offered
again in spring 2020.

Since 2014, Yellowstone Wolf Project staff and over 80

collaborators have been working on a book about wolf
research in Yellowstone which will be released in 2020. Titled
Yellowstone Wolves: Science and Discovery in the World’s First
National Park, the book will feature an in-depth look at wolf
research, results, stories, graphics, and photos from the last
25 years. Hardcover release is expected in October 2020.

Other Programs
Wolf Project Leader Doug Smith, along with other
researchers, advised the gray wolf relocation program at Isle
Royale National Park. The project relocated 13 wolves to the
island during early 2019. Most of the wolves are still alive
and being monitored through GPS collars. The project will
continue in 2020.

Field work is not what you think...notes, notes, and more notes. NPS Photo
- M. Jackson.

6 |Yellowstone Wolf Project Annual Report 2019

Wolf Pack Summaries the females, and the expansion of their territory, it will be
8 Mile (17 wolves: 9 adults, 8 pups) interesting to see if the pack remains cohesive or if they split
The 8 Mile pack experienced an interesting restructuring into two or more groups in 2020.
in early 2019 when the dominant male was injured and the Lamar Canyon (7 wolves: 3 adults, 4 pups)
females started to travel with six new males from the Wapiti Without a radio collar, any information about this pack is
Lake pack. One low-ranking male returned to Wapiti Lake gathered through chance sightings and trail cameras placed
but the rest stayed with 8 Mile in their stable territory and in their traditional territory. A reliable sighting in the fall
the pack denned in two separate locations. Eleven pups were found the pack with the same adult male and female as last
produced and eight lived to the end of the year. The pack winter, with one yearling and four pups. The Lamar Canyon
continues to be led by an uncollared five-year-old female pack began in 2010 and was a dominant force in northern
recognized by her graying, brindle-colored coat. She is only Yellowstone for several years. Since then they have struggled
the second lead female the pack has had since their formation due to a combination of mange and canine distemper
in 2011. outbreaks, wolf hunting outside the park, and pressure from
Phantom Lake (11 wolves: ~4 adults, ~7 pups) larger neighboring packs, all resulting in losses of pack
This new pack (previously known as 1005F group) formed leaders over the years.
in the Hellroaring to Oxbow and Crevice Creek areas left Mollie’s (10 wolves: 6 adults, 4 pups)
vacant after the disintegration of the Crevice Lake pack in Starting with a smaller pack size compared to recent years,
late 2018 and the Prospect Peak pack in late 2017. At least the Mollie’s pack rebounded by producing five pups with
three adult females produced a total of at least 13 pups and all four living through the end of the year. Once again the
survived until early winter when two gray pups disappeared pack anchored their territory in Pelican Valley but made
and two others were harvested during the Montana hunting occasional trips to northern Yellowstone, going as far west
season outside of Yellowstone. After the harvests, one of the as Lava Creek. The pack killed several winter-weakened
radio-collared females appeared injured and alone and the bison despite only having two large males (one of them is
other might be dispersing by the end of the year. Sporadic the second-oldest wolf in the park, eight-year-old 890M)
sightings suggest at least 11 pack members are still alive but and two adult females. In early 2020 Mollie’s pack will reach
are difficult to track without consistent radio-collars. 25 years old (they were released as the Crystal Creek pack
Junction Butte (18 wolves: 10 adults, 8 pups) in 1995), and we can trace the females’ genetic line back
For the second year in a row all four adult females in the through their mother to original Crystal Creek wolves 5F,
Junction Butte pack denned and produced pups. In a strange 6M, and 8M; original Nez Perce wolves 27F, 28M, and 72M;
series of events never before recorded in wild wolves, six and original Rose Creek wolves 9F and 10M.
-year-old subordinate female, 969F, killed all seven of the Wapiti Lake (19 wolves: 10 adults, 9 pups)
three-week old pups from the two most dominant females’ In a rare split the dominant male and female of Wapiti Lake,
den, consuming at least three of them. The event occurred after two and a half years together, went separate ways. The
when the mothers were gone from the den and the pups change was likely precipitated by an inter-pack fight with the
were being tended by two male yearlings. The pack then 8 Mile pack after which six of the Wapiti males remained
helped 969F raise her seven pups. The fourth female, 1109F, with the 8 Mile females. During the next three months the
kept her den and pups separate from the rest of the pack dominant female (the oldest wolf in the park at nine years
and was occasionally helped by beta male 1048M until they old) led the pack’s adult females and all the pups through
merged with 969F’s litter at a rendezvous site in Lamar their traditional territory. Near the peak of the breeding
Valley in mid-September. The litter of seven produced by season, third-ranking male 1014M returned to Wapiti and
969F were exposed to humans at a young age because their was accepted as the new dominant male. The pack produced
den and rendezvous were close to a popular hiking trail two litters totaling nine pups, all of which lived through the
and several people violated the closure in place to keep the end of the year.
wolves from becoming habituated. By winter, several of the
pups were exhibiting severe habituation and were aversively Cougar Creek (6 wolves: 6 adults)
conditioned before two were hit by a vehicle and died. The The Cougar Creek pack split during the denning season with
black yearling male disappeared around this same time and the old dominant male and an adult female shifting west
the pack ended the year with 10 adults and eight pups. Given and the other six pack members remaining in the traditional
the number of breeding adults, the previous tension between territory. One or two females may have localized at a den

Yellowstone Wolf Project Annual Report 2019 | 7

Wolf Habituation and Personality: An Interaction of
Nature, Nurture, and Human Presence
by Kira Cassidy

For much of the last few hundred years in North America, they found some treat along the road (either roadkill or
gray wolves were persecuted and eventually eradicated litter) and kept searching for similar tidbits. In a short time,
from the entire lower 48 states except for a tiny corner of the male became quite comfortable around people and
Minnesota bordering Canada. After reaching their smallest would casually walk through a crowd of visitors, watching
range contraction in the 1940s, natural recolonization and them curiously. Because this behavior can slip quickly
reintroduction programs (including Yellowstone) saw the towards confidence and the chances of being fed by a person
gray wolf slowly, tentatively begin to thrive in areas they’d increase due to proximity, we decided to aversively condition
been absent for decades. No one knows exactly what wolf him with cracker shells. The yearling female also displayed
behavior was shaped by those years of hatred and removal. a nonchalance around the road and vehicles; however, after
Were wolves always scared of humans? A written account by her own aversive conditioning event, both yearlings seemed
William Clark during the 1804 Corps of Discovery Expedition to decide the road was not a good place to linger. They still
described wolves as “fat and extreemly [sic] gentle” and he crossed the road in view of people but did so quickly and
was able to approach them, even killing one with a bayonet. moved well away from the roadway before relaxing. Since
The simple existence of domestic dogs, the descendants of 1995 we have recorded habituated behavior in 55 individuals
wild wolves some 10,000 to 40,000 years ago, suggest that at and almost half of them were aversively conditioned. Only six
least some wolves throughout history grew close to humans, times did the aversive conditioning fail to correct the wolf’s
eventually becoming part of the human family. But for wild behavior, a testament to their mental flexibility, intelligence
wolves, those years of persecution seem to still echo in their and sometimes, determination.
DNA and, being an intelligent creature, they are usually Wolves in Yellowstone den in mid-April, often just a day
extremely wary of humans. or two before whelping. Junction Butte subordinate female
It’s dangerous to speak in absolutes regarding wildlife, 969F chose a den site in a quiet, dense forest. Unfortunately,
especially for an intelligent species where individuals can a popular hiking trail goes through the forest in the summer.
have a wide range of personalities. The visibility of wolves Her den was secluded and safe for the first month or so and
in Yellowstone, combined with research based on following then traffic started to increase. We assumed she would move
marked wolves throughout their entire lives, has afforded her pups because of the human presence near the trail but
us intimate views not only of important patterns in wolf as the weeks went on, the pack continued to secretly raise
life history, but also those anomalies that don’t really fit in their pups in the same area, likely watching and hearing
scientific papers. While most wolves are afraid of people, humans through the trees. Maybe she didn’t want to move
or at the very least avoid them whenever possible, once in a the pups and cross a snow-melt swollen Slough Creek when
while a combination of personality (nature) and environment the pups were so small and could easily drown. Maybe she
(nurture) interact to result in an individual who doesn’t fit worried about their safety as a few weeks earlier she had
the general pattern. killed the pups of the two dominant females in the pack (see
The Junction Butte pack started in 2019 as a stable, pack summary). Maybe she ran into a grizzly sow with two
dominant force consisting of eight adults and three pups in yearlings in western Lamar Valley and decided against leaving
their first winter. It had been almost two years since an adult the safety of a den hole. Maybe she tried to move the pups
wolf died (elderly sw763M in April 2017), so the adults knew but they were reluctant and ran back to the den when they
each other well, a fact evidenced by their prowess fighting heard a bison or a group of people coming down the trail.
other packs and taking down large prey like adult bison. Whatever the reason, we couldn’t force her or the pups to
When spring arrived, the three pups turned to yearlings and move and so instead we worked with YNP Law Enforcement
their personality differences became more apparent. The to set up a “No Off-Trail Travel” zone. We hoped this would
gray male diligently attended the den of the two dominant prevent people from accidentally stumbling onto the den or
females, brought them food, and even babysat the tiny pups sneaking in to see the pups up close.
when their mothers left the den for the first time. We didn’t realize it at the time but several visitors had
The other two yearlings were less interested in the pups and heard or seen the pups on or right next to the trail. Some
the den, instead cruising roadways and pullouts. It’s possible of these people even made the exact wrong choice to hide
8 |Yellowstone Wolf Project Annual Report 2019
Wolf decision-making at its best: what to do now? The lead female (white wolf) brings up the rear, leaving the decision-making up to others. Wapiti Lake pack
in Yancey’s Hole, late December 2019. NPS photo - D. Stahler.

themselves or tried to be nonthreatening, and allowed the Why weren’t all of them confident around people? Or at
pups to get very close for photos. Some people may have least all seven raised near the busy trail? This seems to be a
purposely snuck into the forest near the den closure hoping classic interaction between nature and nurture where even
for a close encounter with the pups. That early contact with though seven were raised in the same place under the same
humans probably influenced the pups’ views of humans as circumstances, only a few had the personality to take those
benign or interesting and may have led to long-term negative experiences and become a human definition of “trouble.”
consequences. This behavior probably contributed to ending the lives of
Eventually the pack did move the pups into Lamar Valley; two of the pups when they were hit by a vehicle on the night
away from people, away from the road, and the autumn of November 19th and died immediately. Wolves often cross
months passed without incident. At least, all incidents were the park road, especially at night when traffic is minimal, but
of the wild variety: bull bison snorting and fighting during a few of the Junction pups had been known to confidently
the rut, some of them dying and providing food for the pack. stand in the road with vehicles approaching during the
Grizzly bears, hungry during a poor seed production year for daytime. The two dead pups, one male and one female, did
whitebark pine, congregated in Lamar to feed on the dead not exactly match the descriptions of the bold ones (black
bison, but the Junction Butte adults taught the pups how to with a large white chest blaze) but because the road-curious
navigate around them. behavior seemed to abate somewhat after the deaths, it is
possible even the curious ones adjusted their behavior after
In late October the pups started to travel full-time with the
the aversive conditioning and maybe even witnessing the
adults, which meant leaving the rendezvous and occasionally
deaths of their litter-mates.
crossing the park road. This time of year is a steep learning
curve for wolf pups and instead of being nervous, several of We live in a world where wild animals are rarely allowed
them were curious, interested in the road and the smelly metal to be bold, even when it is a natural case on one end of the
boxes that roll on it, and even those loud, two-legged animals personality spectrum. However, we have a responsibility to
coming out of the boxes. Over several weeks two or three of help keep them safe from us, too. An encounter with a wild
the pups were deemed “trouble-makers.” One even walked wolf is incredible, and for many people, will etch itself into a
between visitors and grabbed a tripod left on the roadside. lifelong memory; but keeping them safe from humans means
Of the ten pups from two litters, seven of them unfortunately keeping them cautious of us and never approaching a wolf
exposed to human sounds and smells since they were very and never allowing a wolf to approach, even curiously. Park
young, only two of the pups were regularly causing issues regulations prohibit people from getting within 100 yards of
by curiously and boldly approaching human-related items a wolf. That rule isn’t only for the safety of humans but also
like cars and road signs. We were very concerned about this to keep these intelligent animals safe from us and, sometimes,
behavior. When a wolf is close to a human (or developed area their own natural curiosity. Wolves and humans have lived
or road) and unafraid, the story always ends poorly for the alongside each other for millennia and along every level
wolf. Over the weeks we attempted to aversively condition of comfort: wolves as a part of the family to wolves hated
the pups, succeeding only once in scaring one away from the and persecuted. Today, even in a protected, wild place like
road. Yellowstone, wolves are better off afraid of humans.
Yellowstone Wolf Project Annual Report 2019 | 9
briefly but no pups were ever observed. By the end of the
year sightings were even more sporadic and one of the two
collared yearlings traveled to northern Yellowstone while the
other ranged widely but was not seen often and it is unknown
how many wolves remain in the pack.

Bechler (4 wolves: 2 adults, 2 pups)

In collaboration with Utah State University, graduate student
Aaron Bott took on an intensive project attempting to
document wolf and other wildlife movement in the Bechler
region. Bott hiked 485 kilometers (301 miles) and spent 25
nights in Bechler between July and November 2019 gathering
data. Trail cameras in Bechler recorded at least four wolves,
one of them a recognizable gray male seen in previous years,
with another gray adult and two gray pups. The Bechler pack,
which began in 2002, has waxed and waned in numbers,
possibly due to varying winter prey use in the southwest
corner of Yellowstone and wolf hunting in the state of Idaho.

Other wolves
1200M, loner
Collared as part of the Cougar Creek pack, 1200M dispersed Collared as an adult female in Mollie’s pack, 1118F started her own group
from the pack in February but spent March through May in May 2018 before being shot in late October 2018 outside of Yellowstone.
Her rate of travel before the injury was approximately 10.6 km per day. In the
traveling back and forth between his natal pack’s territory and
two months after the injury, she traveled only 1.9 km per day but that was
northern Yellowstone, seemingly alone. Over the summer his
concentrated on just a handful of travel days between feeding for weeks on
movements sometimes overlapped with the Phantom Lake old carcasses she found far up the Lamar drainage on her way back into the
pack but not enough to be considered a part of the pack. park. As the injury healed somewhat and a crust formed on the snow in late
winter, she was able to travel further - for the last 8 months of her life she
1154F, loner traveled an average of 6.2 km per day. As a lone wolf this is a very slow aver-
Born in the 8 Mile pack, 1154F dispersed over the summer age but, considering her injury, 1118F is an exceptional example of tenacity,
and all sightings found her alone through the end of the determination, and grit.
year. She continued to travel throughout traditional 8 Mile
territory but seemed to avoid the main pack. 1118F
After being shot just below the elbow during the 2018 wolf
Crevice Lake
hunting season in Wyoming, wolf 1118F never joined back
In a surprisingly quick disintegration from December 2018
up with the remnants of her pack: her mate and two pups.
to January 2019, the Crevice Lake pack was not located in
She survived by chewing on old carcasses for several weeks
Yellowstone at all in 2019. Several pack members joined
at a time. Once in 2019 she was seen with another gray wolf,
a pack north of Yellowstone monitored by Montana Fish,
possibly her sister from Mollie’s pack. 1118F’s collar switched
Wildlife and Parks, and the pack’s former territory was
into mortality mode in September in a difficult-to-access
quickly filled in by the new Phantom Lake pack.
area deep in Yellowstone’s backcountry. Crews attempting
1104F to retrieve the collar and samples were thwarted by grizzly
Originally born in the Wapiti Lake pack, 1104F dispersed in bears in the area and later attempts were abandoned due to
March but returned to her natal pack for a short time over accumulating snow.
the spring before leaving for good in the summer. Sightings
were rare until winter when 1104F was spotted with a large
uncollared male. The pair moved south towards Grand Teton
National Park by the end of the year.

10 |Yellowstone Wolf Project Annual Report 2019

Publications 2019 Wolf Project Volunteers
Cusack, J.J., M.T. Kohl, M.C. Metz, T.Coulson, D.R. Stahler,
D.W. Smith, and D.R. MacNulty. 2019. Weak spatiotemporal Name Hours
response of prey to predation risk in a freely interacting Adam Fahnestock 320
system. Journal of Animal Ecology 89: 1-12. Annie Stevens 960
Hoy, S.R., D.R. MacNulty, D.W. Smith, D.R. Stahler, X. Lambin,
Ben Breslau 288
R.O. Peterson, J.S. Ruprecht, and J.A. Vucetich. 2019.
Carly Segal 584
Fluctuations in age structure and their variable influence on
Celestina Davidson 288
population growth. Functional Ecology 34:203-16.
Koch, E.M., R. M. Schweizer, T.M. Schweizer, D.R. Stahler, Charlie Southwick 288
D.W. Smith, R.K. Wayne, and J. Novembre. 2019. De novo Gregor Woodruff 296
mutation rate estimation in wolves of known pedigree. Hannah Booth 288
Molecular biology and evolution 36: 2536-2547. Hunter Stier 288
Kohl, M.T., T.K. Ruth, M.C. Metz, D.R. Stahler, D.W. Smith, P.J. Jeremy SunderRaj 320
White, and D.R. MacNulty. 2019. Do prey select for vacant Logan Route 640
hunting domains to minimize a multi-predator threat?. Maddy Jackson 960
Ecology letters 22: 1724-1733.
Micah Jaffe 288
Carter, N.H., J.O. Bruskotter, J.A. Vucetich, R. Crabtree, H.
Nels Christensen 296
Jaicks, G. Karns, M.P. Nelson. D.W. Smith, and J.D.C.
Penelope Haas 296
Linnell. Towards human-wildlife coexistence through the
integration of human and natural systems: a case of grey Taylor Bland 160
wolves in the Rocky Mountains, USA. Pages 384-413 in B. Zach Fogel 640
Frank, J.A. Glikman, and S. Marchini, editors. Human wildlife TOTAL 7,200
interactions: turning conflict into coexistence. Cambridge
BACK COVER: Female wolf 1049F of the Phantom Lake pack tends to her
University Press, Cambridge, England.
pups in early July. This pack had two litters in 2019 totaling 13 pups. NPS
Van Valkenburgh, B., R.O. Peterson, D.W. Smith, D.R. Stahler,
Photo - D. Stahler.
and J.A. Vucetich. 2019. Tooth fracture frequency in gray
wolves reflects prey availability. eLife 2019;8:e48628

Wolf Project Technician Madeline (Maddy) Jackson processes a bison kill likely made by the Junction Butte pack. Later Maddy found evidence that a grizzly
bear chased the wolves off their kill. NPS Photo - A. Stevens.

Yellowstone Wolf Project Annual Report 2019 | 11

 For a complete
For a complete list of our list of our publications,
publications, please visit:
please visit: go.nps.gov/yellwolves

Suggested citation: Smith, D.W., D.R. Stahler, K.A. Cassidy, E. Stahler, M. Metz, C. Meyer, J. Rabe, N. Tatton, J. SunderRaj, L. Carroll,
M. Jackson, B. Cassidy, E. Loggers. 2020. Yellowstone National Park Wolf Project Annual Report 2019. National Park Service,
Yellowstone Center for Resources, Yellowstone National Park, WY, USA, YCR-2020-01.