Yellowstone Ecosystem Fall Grizzly Bear Update
CHEYENNE -- To many people the grizzly bear is a symbol of the ultimate
predator, consuming large amounts of meat for its survival. While this
mental image might pertain to bears found in those parts of North America
where coastal streams still provide an abundance of salmon, grizzly bears
in the Greater Yellowstone Ecosystem have different sources for their much
needed protein throughout the year.
The seeds of the whitebark pine are high in fat content and are an
important fall food as bears prepare for winter hibernation. According to
Mark Haroldson, Wildlife Biologist for the Interagency Grizzly Bear Study
Team at the USGS Northern Rocky Mountain Science Center, “Whitebark pine
cone production was very good this fall, averaging 28 cones per tree on
the 19 transects that the Study Team and cooperators monitor annually
throughout the GYE.”
Bears obtain cones by raiding caches made by red squirrels. “Bears make
nearly exclusive fall use of whitebark pine seed as food during years in
which mean cone production exceeds 20 cones per tree.” Haroldson said. The
high cone production this year means that hunters and other outdoor
recreationists should be aware that bears will be searching for squirrel
caches in mid- to high-elevation conifer stands that contain whitebark
pine. Cone production was similar in 2001, but markedly lower than last
According to Haroldson, “Hunters should not get so focused on pursuit of
game that they miss noting obvious signs of recent bear activity. If
hunters encounter freshly excavated cone caches or fresh bear scat, they
should leave the area.”
Successful hunters are also urged to pack their big game carcass out as
soon as possible after the kill. If some of the carcass remains behind,
hunters should move it as far as possible downwind from the gut pile and
hang the meat in a tree, at least 10 feet high and 4 feet from the trunk.
These actions may help reduce human-bear conflicts that often result in
bear mortality, and occasional human injury, Haroldson said.
As always, hunters and other recreationists should comply with food
storage regulations, and leave a clean camp when they vacate a site.
Problems are created for the next user when unburned garbage is left in
the fire ring, or extra horse cake on the ground. Bears will find these
leavings and use them, and may become conditioned to the site.
Haroldson reports that as of Sept. 2, eight human-caused grizzly bear
mortalities have been documented in the ecosystem. These losses resulted
from a variety of causes, including two from management removal by
biologists, one hit by a vehicle, one a case of mistaken identity, one in
defense of human life, one accidentally killed during a wolf capture
operation and two the victims of malicious killing. Half of these bears
were females. One of these instances occurred more than 10-miles outside
of the U.S. Fish and Wildlife Service Grizzly Bear Recovery Zone and will
not be counted against the annual mortality thresholds established in the
Haroldson also states, “Preliminary results indicate the number of unique
females with cubs of the year observed in the ecosystem this year is at
This is down considerably from the record high of 52 observed during 2002.
A number of factors likely contributed to the lower count this year. The
most obvious is that a lot of females in the population had cubs or
yearlings at their sides last year, and were unavailable for breeding.
Restrictions on aircraft operations due to fires also contributed to the
low number of sightings by limiting searches in some areas of the
ecosystem. The recovery plan is structured so that important population
values are viewed as running averages over a given number of years, this
allows for fluctuations found in nature and human activities.
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