Contents:
Calving Update 2005
How many of the satellite collared cows had calves?
Maps and data provided by Steve Arthur, ADF&G
Calving Update 2005
Caribou began moving towards the calving grounds from their winter ranges in late April - early May 2005. Following traditional migration routes, the caribou that had wintered in the Yukon in the Ogilvie and Hart River Basins moved north between Old Crow and the Driftwood River. Persistent snow cover on the Alaskan coastal plain until June 7th caused many caribou to stop temporarily on the relatively snow-free areas of the Yukon, but others continued west into Alaska. Roughly half of the radio and satellite collared caribou were believed to have calved in the Yukon, and half in Alaska.
The Alaska Department of Fish and Game and the U.S. Fish and Wildlife Service conducted radio-tracking flights between June 4th and 8th, after being delayed by poor weather. Based on the number of calves observed during the survey, it was believed that the peak of calving was between June 1st and 4th, which is earlier than usual. An additional flight was conducted between June 26th and 28th to determine which calves had survived and to estimate the proportion of cows with calves.
Click on map to enlarge
Locations of radiocollared Porcupine caribou cows,
4 - 8 June 2005.
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Seventy-two radiocollared adult cows were observed during early June.
Fifty-five radiocollared cows (64%) were judged to be parturient
(pregnant or had given birth).
This was the lowest parturition rate ever recorded for the herd.
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Sixty-eight cows were located on the late-June flight. Of the cows that were previously observed in early June, 88% were still with a calf.
Click on map to enlarge
Locations of radiocollared Porcupine caribou cows,
26 to 28 June 2005.
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By June 28th, most of the PCH had moved into the Arctic National Wildlife Refuge. Unfortunately, several weeks of cool, cloudy weather began on June 29th, and as a result, the herd failed to aggregate to the extent necessary for a photocensus. The last photocensus of the herd was in 2001. We will try again in 2006.
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How many of the satellite collared cows had calves?
Of the satellite collared cows, Blixen can generally not be observed because of a malfunctioning radio-transmitter (Note: the satellite transmitters give the general location, but the radio-transmitter is needed to actually find the animal). A11 16 other satellite collared caribou were located.
Of these, Catherine, Claudia, Daphey, Helen, Iola, and Pingo had calves that survived through late June.
Arnaq, Bertha, Cocoa, Donner, Kate, Petunia and Tundra were judged to be barren. Rocky (whose satellite transmitter has stopped functioning) and Snowshoe were judged to be parturient but were not seen with calves. * Snowshoe was alive when located June 28th, but died approximately June 30th.
Matilda was seen with a calf in early June but died approximately on June 17th. As noted in the Late winter 2005 fieldwork report, Matilda was originally captured as a yearling in 1998 with Central Arctic Caribou. Matilda stayed with the Central Arctic Herd until March 2004 when the Porcupine Caribou and Central Arctic Caribou were sharing winter range near Arctic Village, Alaska. When the Porcupine Caribou migrated north that spring, Matilda and her calf from 2003 accompanied them. Matilda did not produce a calf in 2004, but with her 2005 calf became the first caribou cow known to have produced a calf with each of these two herds. Because Matilda died, it is unlikely that her 2005 calf survived.
Below is a summary of all caribou and information on whether or not they calved the past SEVEN years.
Note: -- means that the caribou was not located
Download the memorandum by Steve Arthur of the Alaska Department of Fish and
Game
to read the entire 2005 Calving Report as a printer friendly Acrobat pdf file (381 KB)
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