Contents:
Calving Update 2006
How many of the satellite collared cows had calves?
Maps and data provided by Steve Arthur, ADF&G
Download the memorandum by Steve Arthur of the Alaska Department of Fish and
Game
to read the entire 2006 Calving Report as a printer friendly Acrobat pdf file (352 KB)
Calving Update 2006
During the winter of 2005 - 2006, the Porcupine Caribou Herd wintered in 2 major areas: the Ogilvie and Hart River basins of Yukon; and the East Fork, Chandalar River and surrounding hills near Arctic Village in Alaska. Based on data from satellite-collared caribou, the herd did not begin moving toward the calving grounds until May 15th, which is about 2 weeks later than most years. Persistent snowcover did not appear to be a factor in delaying migration, but the caribou did not reach their traditional calving areas in Alaska, and most all calves were born on or near the coastal plain in northern Yukon.
The Alaska Department of Fish and Game and the U.S. Fish and Wildlife Service conducted the annual calving survey radio-tracking flights between June 2nd and 8th. Seventy-one radiocollared cows were observed during these flights. Based on the timing of calves seen, it was believed that the peak of calving was probably June 2nd, which is slightly earlier than usual.
An additional flight was conducted June 25th to determine which calves had survived and to estimate the proportion of cows with calves. Seventy cows were located on the late-June flight. Of the cows that were observed in early June, 86% were still with a calf.
Click on map to enlarge
Locations of radiocollared Porcupine caribou cows,
2 - 8 June 2006.
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Sixty-six of the 71 radiocollared cows (79 %) were judged to be parturient (pregnant or had given birth) which is slightly below average for the past 20 years.
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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,
25 June 2006.
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By June 25th, most of the PCH had moved into the Arctic National Wildlife Refuge. Unfortunately, several weeks of cool, cloudy weather began on June 27th, 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 2007.
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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 12 other satellite collared caribou were located.
Of these, Arnaq, Claudia, Cocoa, Helen and Tundra had calves that survived through late June.
Pingo and Rocky were seen with calves in early June but were alone on June 25th. Kate was judged to be pregnant but was never seen with a calf.
Bertha, Catherine, Daphey, and Donner were judged to be barren.
Below is a summary of all caribou and information on whether or not they calved the past NINE 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 2006 Calving Report as a printer friendly Acrobat pdf file (352 KB)
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