Post-calving Caribou Aggregations
Joly K. 2012. Post-calving Caribou Aggregations. National Park Service. Fairbanks, AK
Post-calving aggregations may be the most spectacular moment of the annual caribou migration cycle. While calving and spring and fall migrations capture the most attention, post-calving aggregations of large caribou herds, such as the Western Arctic Herd, are one of the world’s premier wildlife spectacles. Rivaling the great assemblages of wildlife during the dry season on the African plains, groups of caribou numbering in the hundreds of thousands can quickly form densely-packed aggregations during the short Arctic summer in response to peak insect harassment. Mosquitos, nasal bots and warble flies all plague caribou during this time. In July 2012, approximately 300,000 caribou from the Western Arctic Herd came together near Cape Krusenstern National Monument and Noatak National Preserve (photos above and at right; K. Joly). As insect harassment diminishes, the group splinters as quickly as it formed and animals spread out all over the North Slope and Brooks Range before coming together again for the fall migration.