WISE Science Lecture: The Nelchina Caribou Herd
Heidi working with a sedated animal. Photo courtesy of ADF&G.
On December 18 WISE and our partners held our first Science Lecture of the season, a talk by Alaska Department of Fish and Game Area Wildlife Biologist Heidi Hatcher on the Nelchina Caribou Herd. The talk was held online, which opened it up to people from out of the local area. Interest was huge, with well over 100 people registering, and 96 households logging in to listen.
We started the evening with a look back at the long history between humans and the members of the deer family known as caribou in North America, and reindeer in Europe and Asia. As well as being an important game species for thousands of years, they have been domesticated and used for a wide variety of purposes including dairy production and beasts of burden, a tradition that still continues. They also held a strong place in mythology, which helps explain how we ended up with reindeer pulling Santa’s sleigh. Even Rudolph the Red Nosed Reindeer has an explanation in biology, as their noses have increased blood flow in the winter to keep warm.
In Alaska there are 32 caribou herds, generally named based on their calving areas. The Nelchina Herd is fairly unique in that it usually spends spring, summer, and fall in relatively accessible areas. The herd is in high demand for hunting, and since the 1990’s has been what Heidi described as “a notorious experiment in Caribou management.”
As she reviewed the history and current status, Heidi wryly observed “One thing that’s certain with caribou is that if you try to generalize them they will inevitably find a way to defy the rules that you outline.” There is a basic understanding of the status of the herd since the 1860’s based on oral history and observations. The first scientific census was in 1948, when there were roughly 10,000 caribou. Regular counts began in the 1950’s and continue to this day. Throughout that time there have been drastic fluctuations in the population, range, and average distances travelled. Count estimates range from 10,000 to over 70,000 animals, and the herd has travelled as far as Dawson City, Yukon Territory.
The current management objectives for the herd are to keep it large enough to provide for hunting, but below the carrying capacity of the range. This is challenging for a number of reasons, including the difficulty of getting an accurate count every year, changes in range, switching between herds, and the challenges of “managing” the herd of humans who are hunting.
In the early 80’s an objective of 20,000 adult animals was set, and that number was adjusted over the years. Currently the population goal is 35,000 to 45,000 total animals. Factors including herd size, productivity, and harvestable surplus are used to determine the harvest goals for the following year’s hunting season.
ADF&G uses several methods to gather information on the herd. Every October they put VHS radio collars on 20 female calves. When the animals are captured and drugged for collaring they also collect measurements and biological samples. Weighing the calves helps determine the general status of the nutrition available on the range, which affects the health of the herd. They also have 40-60 GPS satellite collars on animals in the herd which can be tracked more easily from the office. These collars help them determine location and mortality for the herd.
Population counts are also undertaken every summer, but conditions don’t always cooperate. Teams of counters fly a grid of the area in Super Cubs, and depending on the concentration of animals, they are also sometimes able to use special planes equipped with GPS-linked high resolution cameras. Heidi shared an excellent video, Counting Caribou, on the annual counts which can be seen at: https://vimeo.com/471257951.
The researchers also conduct surveys to estimate the number of males, females, and calves in the herd to determine the composition. All of these numbers are combined to come up with population estimates for the year. This information is used by ADF&G to determine hunt quotas to try and achieve a harvest that reaches their objectives. They use these quotas, as well as hunt extensions, emergency closures, and winter openings to help reach the desired harvest rate and gender ratios.
Estimating that a hunter gets 60 to 100 pounds of meat from an animal, each year the Nelchina Caribou Herd produces about 240,000 pounds of food for Alaskans while maintaining a fairly stable population.
It is a challenge to summarize the huge amounts of information Heidi shared in her talk and the question and answer session which followed. The full recording of the December 18th talk can be accessed at the WISE website: www.wise-edu.org.
WISE has more Science Lectures scheduled for January and February, including learning about Copper River Watershed Project’s Salmon Habitat Restoration Projects with Kate Morse (Noon on Friday, January 15) and two lectures exploring Archaeology on the Shorelines of Ancient Lake Atna on February 5th and 12th. To register for any of these online events, you can find registration links on the WISE website. They will also be recorded if you’d like to watch them at a later time.
A huge Thank You to Prince William Sound College for providing technical assistance for these lectures, and to our funding partner Alyeska Pipeline Service Company for financial support. Copper Country Alliance and Wrangell-St. Elias National Park and Preserve are also program partners.
Article by Robin Mayo