Despite a recent report that the population of the Western Arctic Caribou Herd is down by more than half over the last decade, it remains the largest caribou herd in Alaska, according to the state's Department of Fish and Game. A census in 2003 estimated the herd at 490,000 animals, and in 2011, an estimated 325,000 animals remained. That number dropped even more dramatically in more recent years, with a 2013 population estimate coming in at 235,000.
The drop may seem alarming, but in a release from Fish and Game, biologist Jim Dau said that "Caribou numbers fluctuate naturally," and "the current WAH decline is still within the range of change documented for this herd in the past."
Meanwhile, other herds' populations continue to creep up on the Western Arctic Caribou Herd. The Porcupine Herd, which wanders through the Arctic National Wildlife Refuge, numbered an estimated 169,000 animals in 2010, according to Fish and Game.
Though the numbers in the WAH may have dropped recently, it's still a sight to see when the huge group of animals is on the move. This video, shot by Alaska Wilderness Expeditions during the post-calving aggregation northwest of Kotzebue in July of 2013, shows part of the herd around the time of the last census. Alaska Wilderness Expeditions operates out of both Delta Junction and Kotzebue.
Summer is an ideal time to count the caribou, according to Fish and Game.
"Caribou bunch up in the summer in response to insect harassment," the agency wrote in the release. "Radio collars are used to find them and the groups are photographed from the air. The animals in the photos are later counted and herd size is estimated based on the proportion of collars found and their distribution among groups. During the 2013 census, the herd was highly aggregated in a small number of discreet groups, and very few caribou were found outside of the main aggregations."