Their destination is the coastal plain of the Arctic National Wildlife Refuge. By mid-May, the first pregnant cows arrive, followed soon by the rest of the herd. Calving reaches a peak in early June. The narrow coastal plain between the Brooks Mountain Range to the south and the Arctic Ocean to the north is ideal for calving and the early nurturing of the young. Thick fields of protein-rich cottongrass provide nourishment.
Ocean breezes hold back swarms of mosquitoes.
Predators in this season are few. The coastal plain is so perfect for this purpose that, although it is only one-fifth the size of the calving area used by the Central Arctic caribou herd, six times as many Porcupine caribou inhabit it. By early September, the young calves are sturdy enough to begin the migration southward. The cycle begins again. Caribou are forever.