The focus of this study was the distribution,
abundance, and calf production of Central
Arctic Herd (CAH) caribou between the
Colville and Kuparuk rivers in northern Alaska
from spring to fall 2012. Surveys were
conducted in spring (mid-May), the calving
season (early June), postcalving (late June),
late summer (mid-August), and fall (early
October). Another survey planned for
mid-September was cancelled due to poor
weather. No surveys were scheduled during the
insect season in July. Incidental sightings of
other species of large mammals were recorded
during aerial surveys for caribou and other
species (mainly birds).
A fixed-wing airplane was used to survey the
distribution and abundance of caribou once
during calving in 2012 (8–10 June). An earlier
calving survey was not completed due to
persistent fog and other inclement weather in
early June. Summary maps of caribou density
were prepared to compare calving distribution
and density in 2012 with long-term averages
from regional calving surveys conducted since
1993. A helicopter was used to sample the age
and sex composition of caribou groups on 12
June.