Today's News
A/CPB
Caribou Migration Update: May 15, 1997
USFWS
| To: | Journey North |
| From: | Robert Mulders, NWT Dept. of Renewable Resources |
| Date: | May 15, 1997 |
"Dear Students,
"Although we had a week of warm weather in late April, temperatures have cooled off again (-20 to 0C). We had a bit of a blizzard yesterday, and so far it appears that we may have a late spring. The snow buntings arrived earlier this month, and a few small flocks of geese (Canada and Lesser Snow) have been spotted.....and the caribou continue to move toward the calving grounds.
- Link to Today's Migration Data
"Based on our past survey experience, weather on the calving grounds tends to be fairly miserable. Despite snow, rain, and fog, caribou appear to be superably adapted to successfully deliver calves under these generally cold conditions.
Gov't. of the Northwest Territories
"Calving for the Qamanirjuaq herd tends to peak around June 6-12 according to our past surveys. Although a very small proportion of the females may be cropping their calves before June, calving is fairly synchronized with perhaps 50% of the calving complete by say aorund June 9. The vast majority of cows will have calved by mid-June.
"The main indication we receive from satellite collars that calving is taking place is the fact that the caribou tend to stop moving. Just prior to calving, females slow down and try to find a quiet spot to give birth. Shortly after the peak of calving, females start to concentrate into larger groups, and start to move off of their calving grounds with their fairly mobile new calves. The temperature (ambient air) and activity (motion) sensors on the collar offer little information on the actual timing of calving.
Gov't. of the Northwest Territories
"Usually, a large % or proportion of the calves tend to survive the calving period. When we periodically conduct census work we collect any dead calves and do a necropsy to try to determine the cause of death. Several primary factors which contribute to calf mortality include: Predation, starvation due to abandonment or inexperience by young female caribou, and potentially bad weather (i.e. freezing rain). We don't have good data on calf mortality in June, but we believe that survival tends to be quite high, say greater than 95%. Spring composition data done in April each year suggests that anywhere from 40-65% of the calves have survived their first 10 months of life and will likely be recruited to the herd.
"Wolves are the most common predator at calving time. Based on wolf sighting information during our surveys, it appears that wolves are more common on the Beverly range than on the Qamanirjuaq range. This may be a reflection of the greater level of Inuit hunting of wolves on the Qamanirjuaq range. Barren ground grizzly bears also take advantage of the calving period by either running down caribou, or by ambushing calves or vulnerable caribou in areas of soft snow. Occasionally, Glaucous gulls (Larus hyperboreus) have been known to peck at the head of eyes of an unattended sleeping calf, and are capable of actually killing them as well. A number of species also take advantage of the opportunity to scavenge on a dead caribou.
USFWS
"Dave and I are planning to go out over the next day or so to remove a satellite collar from that female grizzly bear. We will also remove the collar from one of the caribou we've been tracking, #3926.
"Later this week-end I'm off to Yellowknife to start a new position with our department as Wildlife Biologist (carnivore/Fur Bearer). The field projects involved will likely include wolverine, lynx, marten, grizzly bear, and possibly wolves. With better access in Yellowknife to Internet facilities, I'll be able to more easily communicate with the outside world! Dave Abernathy is continuing on as the Wildlife Technician here in Arviat and will provide updates on the remaining 2 caribou collars for the remainder of the spring.
"Best wishes to the staff of Journey North, and the many teachers who facilitate and students who participate in this great program. This focus on wildlife migraiton is an excellent means of stimulating interest and awareness of our environment and the fascinating field of wildlife biology."
Cheers,
Robert Mulders
Arviat, NT
A Note from Journey North
Although our final update is scheduled in 2 weeks to coincide with the end of the school year, we will provide caribou data through the calving season. This will ensure we have a complete data set on the WWW for use in the future by students.
The FINAL Caribou Migration Update Will be Provided on May 29, 1997.