MONTANA DEPARTMENT OF FISH, WILDLIFE AND PARKS
Elk numbers
in Yellowstone National Park’s northern herd are fewer compared to last year,
however the population remains above the 10-year average and other recent
counts. Low calf survival will likely impact the population over the next two
years, according to a population survey conducted last month.
The Northern
Yellowstone Cooperative Wildlife Working Group, which consists of staff from
the Montana Department of Fish, Wildlife and Parks, National Park Service, U.S.
Forest Service and U.S. Geological Survey-Northern Rocky Mountain Science
Center, conducted its annual late winter classification of the northern
Yellowstone elk population on March 17-19.
All observed
elk were counted across the survey area, and when possible, staff also
classified elk by age and sex. This survey was conducted consistently with the
2016 classification survey in order to assess population changes over the past
three years. Survey conditions were favorable across the region; however,
winter conditions were severe, and many elk were observed to be in poor
condition.
Staff
counted 5,800 elk total, which included 1,361 elk, or 23.5 percent, inside
Yellowstone National Park and 4,149 elk, or 71.5 percent, north of the park.
The total count was 23 percent lower than the 7,579 elk observed during the
2018 trend count, and 23 percent lower than the 7,510 total elk counted during
the 2016 classification survey, but higher than the 10-year average count of
5,399 elk. The long-term average of observed elk numbers since surveys began in
1976 is 10,634 elk, with a peak-high count of 19,045 elk in 1994 and a low
count of 3,915 in 2013.
Of the 5,800
elk counted, staff classified 5,510 elk by age and sex, resulting in ratios of
15.2 calves, 5.2 yearling bulls and 12.6 brow-tined bulls per 100 cows. Calf
and yearling bull ratios were lower than recent surveys and long-term averages.
Brow-tined bull ratios were higher than recent surveys, but below long-term
average. Staff observed 16 percent fewer cows, 46 percent fewer calves and 42
percent fewer yearling bulls as compared to the 2016 classification survey.
Brow-tined bull numbers increased by 21.3 percent from 432 observed in 2016 to
524 observed in 2019.
This is the
second consecutive year with calf ratios below the threshold of 20 calves per
100 cows considered necessary to maintain a stable population. It’s likely that
additional winter mortalities will occur into spring, further reducing overall
numbers and recruitment. Below-average yearling bull and calf recruitment is
likely to result in lower numbers of brow-tined bulls being recruited into the
population over the next two years.
Though
overall elk numbers are down this year as compared to 2018, it’s not unusual to
observe fluctuations in numbers of elk counted due to survey quality, elk
movements and sight-ability of elk, which vary with conditions. Trends in elk
populations are best assessed by considering multiple years of survey data
together. The trend for this population has been increasing since 2013; this is
the first year since 2013 that elk numbers have fallen from the previous year.
The working group will continue to monitor trends of the northern Yellowstone
elk population and evaluate the relative contribution of various components of
mortality, including predation, environmental factors and hunting.
The working group was formed in 1974 to cooperatively preserve and protect the long-term integrity oft he northern Yellowstone winter range for wildlife species by increasing our scientific knowledge of the species and their habitats, promoting prudent land management activities, and encouraging an interagency approach to answering questions and solving problems.
