During the spring of 2000, Porcupine Caribou cows began their northward migration later than usual and did not reach their traditional core calving area until late June. The delay in migration is probably related to the late spring and persistent snow cover experienced in the Northern Yukon and Alaska north of the Porcupine River. Delayed migration resulted in calves being born along the migration routes, which likely contributed to the low calf survival. Caribou were observed migrating with newborn calves and residents of Old Crow reported seeing calves swimming the Porcupine River. Gus-Gus died 31 May during migration, just north of the Porcupine River.

Between May 30th and June 10th, and June 31st and July 1st, radio-tracking flights were conducted by Alaskan Biologists to locate radio-collared caribou cows and to observe whether they had produced calves. Forty-six radio-collared cows were observed during this time period. The number of collared cows that gave birth, the number of calves surviving to July 1st, and the number of calves per 100 cows were among the lowest on record.

The peak of calving was also about one week later than usual. Typically, the peak of calving is around June 1st, and by June 5th most calves have been born. During the spring of 2000, the peak of calving was around June 7th.

The birth rate for the herd is usually 80 or 90%, but in 2000 it was estimated that only 32 of the 46, or 71% of our radio-collared cows gave birth. Only 20 of the 32 calves born survived to July 1st. This survival is less than during any year from 1991 - 1999.

Of the satellite collared cows, Lucky 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). Both of these caribou did travel to the calving grounds and likely were pregnant. Cupid, Donner, and Isabella produced calves that survived to July 1st. Lynetta was judged to be pregnant but had not given birth by June 10th, and was not located during the follow-up flights June 31st and July 1st. Both Trudy and Lupine had calves at heel when they were captured July 1st.

Below is a summary of all caribou and information on whether or not they calved the past three years.
Note: -- means that the caribou was not located

Every 3 years, during the large groupings of caribou (called post-calving aggregations), a photocensus is done. The groups of caribou are located by plane and when they form very tight groups of animals, another plane with a large format camera mounted on the belly flies over and takes photographs. The photos are developed and we count the caribou in the photos. The locations that we get from the satellite-collared cows are extremely important for helping us find these big groupings.

The last time the herd was censused was in 1998. At that time the herd numbered 129,000. We had intended on conducting a photocensus July 2000, 1 year ahead of the normal schedule. Unfortunately, weather conditions were such that the caribou did not aggregate, and a census was not possible. July 2001, we will again try to do a photocensus. Hopefully the weather and the caribou will be more cooperative this time.

If you have any questions, please contact: Dorothy Cooley or Martin Kienzler Regional Management Box 600 Dawson City, YT Y0B 1G0 Phone (867) 993 ­ 6461 Fax (867) 993 ­ 6548 Emaildorothy.cooley@gov.yk.ca or martin.kienzler@gov.yk.ca