Porcupine caribou herd numbers highest in monitoring history

Caribou are captured in a photograph taken last summer by a digital camera mounted in a small aircraft. (Photo courtesy ©Alaska Department of Fish and Game)

The Porcupine caribou herd, whose range includes the Arctic National Wildlife Refuge, has grown to the highest number seen since monitoring started back in the 1970s. That’s according to the Alaska Department of Fish and Game, which just released the results of a photocensus they did this summer.

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That census is done by mounting cameras to small aircraft, and taking aerial pictures of the herd during the short window they aggregate during the summer.

The new count puts the herd at an estimated 218,000 animals. For comparison, the low point was 123,000 – back in 2001.

The growth is part of an upward trend for the Porcupine herd; the surveys taken in 2010, 2013, and 2017 all show an increase.

“We’ve definitely had an improvement in calf production and adult female survival,” said Jason Caikoski, a wildlife biologist with the Alaska Department of Fish and Game. But he says that while they can identify things that explain how this caribou population is growing, they still don’t know the underlying causes that explain why.

“Predation, changes in weather, changes in habitat… all those types of things affect all those demographics,” Caikoski said. “And currently we don’t have any studies specifically looking at what factors are affecting those demographics.”

Photocensus counts are used by state and federal wildlife managers to help set hunting limits and seasons. Sometimes a finding will prompt a change in regulation, but in the case of the Porcupine caribou herd, which has a moderate population and low hunting pressure, no changes are anticipated.