Near-record grizzly cubs in Yellowstone
BILLINGS, Mont. ” An abundance of protein-packed, whitebark pine nuts apparently helped a near-record 50 female grizzlies produce cubs this year in and around Yellowstone National Park.
Yellowstone biologists counted 52 female grizzlies with cubs in 2002.
Chuck Schwartz, leader of the Interagency Grizzly Bear Study Team, said the numbers released Wednesday are typical after a year with good production of whitebark pine nuts, which grizzlies rely on for food.
“We see these pulses,” Schwartz said. Fewer females are expected to have cubs next year, because the females who had cubs this year won’t breed next year, he said.
Also in years following a good pine nut crop, females tend to produce more three-cub litters. This year, 18 of 50 litters observed had three cubs.
Biologists conduct an annual tally of female grizzlies with cubs of the year as a way to gauge the overall health of the population. Last year, 46 were observed; in 2005, there were 31.
Wildlife officials still estimate the overall grizzly population inside Yellowstone and in the “recovery zone” outside the park is 400 to 600, although Schwartz said that’s a conservative figure.
Earlier this year, Yellowstone grizzlies were taken off the endangered species list, a decision that’s being challenged by environmental groups.
Bear biologists also witnessed a fairly rare sight this year.
They believe a female grizzly near Yellowstone’s Dunraven Pass may have adopted two cubs. Two family groups were split up in early August apparently by a pack of wolves. When they came back together, two of the cubs appeared to be with a female that wasn’t their mother.
Cub adoption hasn’t been observed in Yellowstone since the early 1970s, Schwartz said. DNA analysis is being done on hair samples from the bears to see if the cubs had been taken in by another bear.
Billings Gazette, http://www.billingsgazette.com
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