Contents:
Updated April 25, 2006
March 2006 Porcupine Caribou Fieldwork
Winter Satellite Locations
Telemetry relocation
Capture locations
Composition count data
Dempster Snow Stations
Winter satellite collar locations
Click on maps to enlarge
Movements of Satellite collared cow caribou during Rut and late Fall, October 1 to November 30, 2005
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During the first week of October 2005, Porcupine Caribou began to move toward winter ranges. Those caribou north of the Old Crow Flats moved into Alaska, while those near the Richardson Mountains headed south to Yukon winter ranges.
By the middle of October, Porcupine Caribou in the Yukon were seen further south than their usual limit, getting as far down the Dempster Highway as km 14. Caribou in Alaska concentrated around Arctic Village.
Movements of Satellite collared cow caribou during winter months, December 1, 2005 to March 31, 2006
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From about the middle of November 2005 till March 2006, the caribou moved very little. Judging by the distribution of radio and satellite collars, the Porcupine Caribou herd was near equally split between Yukon and Alaska throughout the winter months.
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Telemetry relocations
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Locations of radio and satellite collared caribou, March 6 to 15, 2006
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On March 6, Tara Wertz and Dave Sowards with the U.S. Fish and Wildlife Service (Arctic National Wildlife Refuge) conducted a telemetry flight in Alaska and found 26 radio collared and 7 satellite collared Porcupine caribou.
On March 14 and 15, Tara and Dave flew the Yukon portion of the range, locating 28 radio collars and 6 satellite collars. This included "Rocky", whose satellite transmitter failed in January 2005, but whose radio transmitter was still functioning.
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Location of radio and satellite collared Porcupine, Central Arctic, and Hart River Caribou, March 2006
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Also in March, telemetry flights to relocate collared Central Arctic Caribou in Alaska by Alaska Department of Fish and Game biologists, and Hart River Caribou in the Yukon by YTG employees indicated that Porcupine Caribou were mixed in with these other herds on respective overlapping winter ranges.
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Capture locations
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Locations of caribou captured March 13 to 21 for deployment of radio and satellite collars
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The goal this March was to replace radio and satellite collars that were due to go off the air, and to add more radio collars to adult cows, calves and bulls in preparation for a census July 2006.
The radio collars that needed replacing were on female caribou caught when they were 9 months old (short yearlings) in March 2003. Since 2003, 10 short yearling females have been collared each spring to start gathering information on the survival of calves between March and June/July of their first year. 7 of these caribou, now nearly 4 years old, were located and recaptured. All were in good condition and at least 2 of them were still accompanied by calves.
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"Claudia"
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In Alaska, Porcupine Caribou captures took place March 13 and 14 in conjunction with other fieldwork involving Central Arctic Caribou. Martin Kienzler with YTG Environment went over to assist Alaska Department of Fish and Game Biologists Steve Arthur and Patty Delvecchio. Rick Swisher of Quicksilver Aviation piloted the Robinson-44 helicopter for the captures, and Marty Webb provided aerial telemetry support with a Supercub.
Captures in the Yukon occurred between March 18 and 21. Conservation Officer Russel Oborne and Yukon Parks staff Geoff Crammond and Alice McCulley assisted Martin Kienzler with these efforts, piloted by Karl Scholz of Fireweed Helicopters.
This year we did not add any new caribou to the satellite program, as there were many older collars that needed to be replaced. In Alaska, Kate, Claudia, Helen and Arnaq were recaptured and collared with new satellite transmitters. In the Yukon, Bertha, Rocky, Tundra, Donner, and Iola were recaptured. All but Iola received new satellite collars. As we did not have enough new satellite collars to replace all the old ones, Iola was recollared with a VHF transmitter, and therefore will no longer be followed by the satellite program. It is possible that we may replace Iola's radio collar with another satellite collar in the future.
Of interest, this is the 5th time that Donner has received a new collar. Of the original 10 caribou collared at the start of this program during the fall of 1997, Donner and Blixen are the only ones still alive. All caribou were adults when caught, so at least 3 years of age. This would mean that Donner and Blixen are a minimum of 11 years old now.
Blixen can not be located on the ground because her radio transmitter has failed, though her satellite transmitter continues to work. Donner was in very good shape this spring, and will hopefully be around for a few more years.
Composition count data
We were not able to conduct the March Composition Count this year because the caribou herds were mixed on much of the winter ranges, both sides of the border. During composition counts, caribou are classified as Cows, Calves, Mature bulls, and Immature bulls. Comp counts are useful in obtaining an estimate of overwinter survival of calves. However, to obtain an accurate representation of survival for a herd, it is necessary to classify caribou in as many wintering areas as possible as there can be differences between ranges.
Dempster Snow Stations
In 1991, YTG set up 8 stations along the Yukon portion of the Dempster Highway in Porcupine Caribou range to monitor late winter snow accumulation and density over the long term. These stations were established in treed and open tundra terrain. Caribou winter use regions were defined in the early 1980's. The Dempster Highway passes through 3 of these regions (Richardson, Eagle and Ogilvie).
The 8 snow stations were measured by Dorothy Cooley on March 22nd and 23rd. Snow depths were slightly above average in the Ogilvie and Eagle Regions, but below average in the Richardson section. Densities were average to slightly below average in the Ogilvie and Eagle Plains regions, respectively. Snow weights were not recorded for stations north of Eagle Plains due to high winds at the time of field work. No ice layers were noted at any stations. Station # 8 at Kilometer 340 on Eagle Plains burned in the summer of 2005.
Download the Dempster Snow Report as a printer friendly Acrobat pdf file (415 KB)
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