Harbor Moose Population Drops To 500!. (Click Moose for the Big Picture.) Bet that headline got your attention. OK, so the moose in mind are all on Isle Royale, but it is Eagle Harbor Township...at least the west half of the island.(East half is Houghton Township...not sure why since on the peninsula Eagle Harbor Township is east of Houghton Township.) Anyway, the big news from last winter's annual census of Isle Royale moose and wolf population is the decimation of the moose.
Just two years ago there were 2400 moose on the island, the most ever and many more than the island's fragil ecosystem could support. Visitors to the island the last two summers could walk through forests that had absolutely no growth from the ground up as high as the moose could reach to browse. The severe winter of 1995-1996 severly stressed the herd. Half of them died as lack of food, the deep snow and a heavy investation of winter ticks took their toll. The final blow for the surviving moose was the late arrival of the spring greenup a year ago.
But nobody anticipated that over this past winter another 700 would die. They simply starved. The moose, which had almost become a nuisance for island visitors, are now once again a rare and welcomed sight.
Winter '97-'98 Wolf Count Update. Rolf Peterson, MTU professor and long-time director of the Isle Royale wolf-moose project, reports that 13 of the 24 wolves spotted on Isle Royale last winter have died. Three pups were born, leaving the island's wolf population at 14. A slight increase in the wolf numbers had been expected. The cause is unknown, although the 80% decline in the moose population over the past two years had decimated the old and weak moose, the animals wolves most often prey on. It is also possible that there has been another outbreak of canine parvovirus, the deadly virus found in domestic and wild dogs that all but wiped out the wolf population in the 1980's. The wolf count peaked at 50 in 1980. The disease had been carried to the island by a pet brought to the island by a park visitor. Pets are not permitted on the island for this reason.
Winter '98-'99 Wolf & Moose Count Update. Wow, what a difference a year made. Even the researchers were amazed to find that the wolf count almost doubled, from 14 to 25. The middle and eastern island packs produced six surviving pups each. The west island pack is the smallest and had no surviving pups, a result of few moose at that end of the island. Rolf Peterson says the wolves are finding the moose easy prey. Many of the moose are reaching old age and there are more calves - both prime targets for the wolves. Peterson noted that moose population increased slightly, from 700 to 750. He said many of the moose are in poor condition. The relatively warm winter encouraged heavy winter tick infestation, a deadly situation for moose, and the record heat of last summer made it difficult for moose to put on much fat, fat they need to survive through the winter.
Winter '99-'00 Wolf & Moose Count Update.The gray wolf population has risen to 29, two years after a sharp drop to 14 prompted fears the animals' days on the island might be numbered. Professor Peterson's latest survey reports five new pups and the death of one adult male, apparently in a fight with other wolves. Peterson, who has studied the predator-prey relationship between the island's wolves and moose for 30 years, now concludes that the sharp dropoff in the wolf population two years ago was a one-time setback resulting from the major die-off of moose,the wolves' principal food source. The moose count again increased slightly, from 750 to 850, about a third of its peak in 1995. Peterson characterized the current moose population as "manageable". The wolves and moose all appear to be in good health and experiencing normal reproductive success.
Winter '04-'05 Moose and Wolf Count Update.The moose count fell to about 540 this year, down from 740 last year and 1,100 during the winter of 2002-03. Meanwhile, wolf numbers jumped from 19 to 29 last season and reached 30 this year. Scientists say the moose might be feeling the effects of long-term challenges such as global warming and the shortage of balsam fir, their primary food source in winter.A recent warming trend has borne a bumper crop of ticks. Tens of thousands can attach themselves to a single moose, each sucking a cubic centiimeter of bllod. The agonized moose spend so much time rubbing against trees and biting their hair, they neglect to fatten up for the winter. Weak from hunger and blood loss, they are less capable of fighting off wolves. The moose dropoff may result in the wolves running short of prey and invading each other's territory, leading to their own decline. The island had only 18 moose for every wolf this year, the ratio usually is between 30 and 70 moose per wolf.
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