Western Arctic Herd caribou cows are slow on their 2012 spring migration north to their calving grounds. Only 40% of GPS collared cows have crossed the Kobuk River as of May 19th, which is less than the 59% that had crossed in 2010 and the 81% in 2011. The numbers would be more dramatic if it were not for the fact that more collared caribou had wintered north of the Kobuk River (25%) than the previous two winters (0-19%). On average, the cows are more than 40 miles farther south this May than the previous two years. However, many caribou were still on the Seward Peninsula so they have to travel east as well as make up the distance to the north. Late migration can be caused by winter conditions and lead to poor calf survival. Alternatively, late migration could be due to more non-pregnant females that tend to migrate later than pregnant cows.

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Published on Jun 6, 2012