Schandelmeier: Autumn brings annual caribou migration

Daily News correspondentOctober 1, 2013 

Caribou from the Porcupine herd gather in a drainage of the Brooks Range in ANWR, June 2009.

RICHARD MURPHY — Anchorage Daily News archive

There is snow in the mountains and the caribou herds are beginning their fall migrations. And Alaska has a lot of caribou that need to move.

The total caribou population in Alaska, including those shared with Canada, is more than 900,000. There are 32 separate herds. They may share some of the same winter range, but they have separate calving grounds. The largest herd is the Western Arctic, which numbers about 300,000. This herd also moves the farthest. Fall migrations of 300 or 400 miles are usual.

Some caribou do not move at all. The small Chisana herd, which is considered to be the only group of woodland caribou in Alaska, stays put. These caribou spend their lives along the Alaska/Yukon border. Hard winters and predation have taken a toll, and the group is in decline.

Most of the herds in Alaska begin their annual fall migrations to their wintering areas by early October. We can't be sure what triggers caribou migrations. Weather is a major factor, though not the only one. Caribou of the same general herd, scattered many miles apart, begin to move almost simultaneously. A caribou biologist who has been studying the Western Arctic herd for the past three decades believes caribou may have sensory capabilities beyond our understanding.

Caribou are definitely a different-thinking animal. Twice in the past year I have been run over by caribou that would not detour from their path.

This fall on the Denali Highway, a small group of caribou, intent on crossing the road, ran through the middle of the dog team I was training. Last winter, while traveling on the trapline by snowmobile, I was hit by a single cow that was trailing a larger herd. It seems that predation on a single animal may not be as important as the health of the entire herd.

Predation is a major factor in the size of our herds. Fire is also a concern. Large wildfires destroy the lichen that is one of the major food sources for caribou. It may take as long as 60 years for lichen to recover from fire.

Caribou will also feed on sedges, felt-leaf willow and other small shrubs such as lowbush cranberry and blueberry. Caribou dig through snow for their feed, and wet snows that freeze hard make low-growing species tough to access. The energy required to feed may be more than they get in return.

The most familiar group of caribou to Southcentral Alaskans is the Nelchina herd. If you were on the Denali Highway this fall, it may seem like hunting pressure is a major predation factor. However, hunters take less than 10 percent of this herd, and only two percent of herds statewide.

This season's late spring caused substantial calf mortality in the Nelchina herd. Fires near the wintering areas have degraded range, causing the animals to move into unfamiliar areas. Despite setbacks, this is generally a healthy, increasing herd.

Caribou and reindeer are considered to be the same species, and most of Alaska's caribou herds have had an infusion of reindeer genetics at one time or another. Reindeer herds on the Seward Peninsula have mixed with the Arctic herds. These reindeer herds were substantial and certainly affected the genetics of the caribou they were in contact with.

In October 1921, a herd of 1,160 reindeer left Good News Bay near Bristol Bay accompanied by six herders. They trekked 1,200 miles to Cantwell, arriving in early August of 1922. These animals were brought in to help out the local Athabascans and to feed the miners working at Valdez Creek. Due to lack of interest in herding and the presence of the Nelchina caribou, they soon interspersed into the wild.

How these out-crossings have affected our caribou populations are unknown. Overall, reindeer and caribou are pretty similar, although reindeer cycle somewhat differently. Their rut typically begins a month earlier than that of caribou, resulting in earlier calving.

Reindeer are stockier and smaller. These characteristics have likely been long bred out of the general populations. Cows breed for less than 10 years, so the herd turns over relatively quickly.

Bulls don't live as long, and usually don't breed until they are 4 years old. Thus, a bull/cow ratio of 25-to-40 is necessary for good herd health. Calf mortality can be upwards of 75 percent in some seasons, slowing herd growth.

Despite wildfires, heavy snow and predation, Alaska's caribou population continues to be strong. And this fall, as since time began, they are on the move.

John Schandelmeier is a lifelong Alaskan who is a commercial fisherman in Bristol Bay and a two-time Yukon Quest winner. He lives near Paxson.

 

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