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Contents: Calving Update 2001 How did calving in 2001 compare to past years? How many of the satellite collared cows had calves? How many caribou are there now? For the second year in a row since we have been watching these satellite collared cows, Porcupine Caribou cows began their northward migration later than usual and did not reach their traditional core calving area in the '1002' lands until late June / early July. The delay in migration is most certainly related to the late spring and persistent snow cover experienced in the Northern Yukon and Alaska north of the Porcupine River. The satellite collared cows didn't leave their winter ranges until May 18th. Delayed migration resulted in calves being born along the migration routes, some of them south of the Porcupine River in Yukon. About half of the cows did reach calving habitat along the coastal plain in Yukon, but still far from their core calving grounds in Alaska. Movements of the Porcupine Caribou Herd during calving, June 1 to 10, 2001.
How did calving in 2001 compare to past years? Between May 30th and June 10th, and June 31st and July 3rd, radio-tracking flights were conducted by Alaskan Biologists to locate radio-collared caribou cows and to observe whether they had produced calves. The peak of calving this year was about one week later than usual, similar to last year. Typically, the peak of calving is around June 1st, and by June 5th most calves have been born. During the spring of 2001, the peak of calving was again around June 7th. The birth rate for the herd was on the low side of average, as 59 of the 70 radio-collared cows (84 %) observed were pregnant or gave birth. At the end of June, 61 % of calves born were still alive. This represents a ratio of 51 calves per 100 cows, which is higher than it was in 2000, but is below the average of 60-65 calves per 100 cows surviving their first month of life.
How many of the satellite collared cows had calves? Of the satellite collared cows, Lucky, Lynetta and Blixen can generally not be observed because of malfunctioning radio-transmitters (Note: the satellite transmitters give the general location, but the radio-transmitter is needed to actually find the animal). All three of these caribou did travel to the calving grounds and likely were pregnant. Of the satellite collared caribou that were located, only Donner had a calf at heel during the flights in early June. Isabella was judged to be pregnant by the presence of antlers and an udder. Cupid and Trudy were accompanied by yearlings, which were possibly last years calves. During the post calving flights in late June, all caribou but Blixen, Lucky and Lynetta were again located, and only Donner had a calf.
 Herd Update: How many caribou are there now? Its taken a while, but biologists have completed the task of counting caribou from the 414 photos that were taken July 3rd during the 2001 census. The current estimate for the Porcupine Caribou Herd is 123,000. While the herd size is smaller than in 1998, the rate of decline has slowed.
To view a graph showing herd size estimates since 1953, click here
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