Wildlife cannot be counted exactly, but populations can be estimated accurately. NPS photo/Mary Lewandowski.
Apart from the road corridor and the areas around park facilities, Denali National Park and Preserve is more than 9,000 square miles of wild country, room for large animals to roam, migrate, rest, spar, browse and dodge predators. In 1938 the park naturalist Joseph Dixon noted that moose were increasing and had become quite common in what was then Mount McKinley National Park. Today's biologists estimate numbers rather than count them, and trends, along with the quality and spread of the habitat that gives animals food and cover, matter as much as any single figure.
How the estimates are made
Most come from aerial surveys. A trained observer counts animals as a pilot flies a small plane along standard routes, sometimes following signals from radio-collared animals to find uncollared ones in the same group. The number seen per square mile, and the share of suitable habitat covered, give an estimate for the whole park. Estimates are often made separately for the north and south sides of the Alaska Range, and when a survey is flown makes a big difference.
The estimates (as of 2023)
| Species | Estimate | Basis |
|---|---|---|
| Grizzly bears | about 300–350 north of the Alaska Range (about 70 per 1,000 mi², or 27 per 1,000 km²); about 72 per 1,000 mi² (28 per 1,000 km²) on the south side, likely higher there because of more salmon streams | radio-collared bears south and west of Wonder Lake, extrapolated; mid-1990s surveys, the latest available |
| Black bears | about 200 in the park's south side | Alaska Department of Fish and Game estimate of about 2700 in Game Management Unit 16 (about 334 per 1,000 mi², 131 per 1,000 km²), scaled to the park's share of unit 16B; early-2000s work; no formal surveys north of the range |
| Wolves | about 105 in spring 2022, in 14 monitored packs (15 by fall) | radio tracking flights and Iridium collars; 14 of the 15 packs denned, and 13 raised pups that survived to fall |
| Caribou | about 1,510 in fall 2022 (preliminary), down from 2,060 in 2021 | parkwide count of the Denali Herd, in decline since 2018 |
| Moose | 509 seen in a 419 mi² (1,085 km²) area near Cantwell in December 2018, stable or rising slightly; 1,743 estimated north of the range in 2017, similar to 2015 and slightly above the early 2000s | aerial surveys, now on hold (2023) while methods are reviewed |
| Dall sheep | about 1,100 – 2,000 north of the range, 2011 to 2020 | new aerial methods being tested; updated estimates forthcoming |
Dall sheep at an unusually low spot in the mountains. NPS photo/Katie Thoresen.
Why exact numbers are elusive
- Births and deaths change numbers constantly.
- Animals move in and out of the park; a boundary means nothing to them.
- Estimates from one area are extended to others with similar habitat, and that assumption has limits.
- Some estimates rest on counts spread over several years, each in a different place.
- Surveys stop when there is no snow to show animals against, or when weather grounds the planes.
Beyond the numbers
Surveys are flown often enough to estimate numbers and spot trends, but researchers also study movements, the number of young, health, survival, diet and choice of mates. Together these help park managers look after the species, with the aim of keeping wildlife populations' natural ups and downs intact.
Sources
- National Park Service, Denali National Park and Preserve, "Large Mammals in Denali: How Many Are There?" (last updated April 2023). https://www.nps.gov/articles/denali-animal-count.htm
- Joseph Dixon, Birds and Mammals of Mount McKinley National Park (1938).
In these publicationsDenali National Park & Preserve
Licence: CC0 1.0 (public domain) · Adapted from www.nps.gov
1
0
0
0
Comments
