Clam Lake Elk Herd Updates
Second Quarter— April through June 2009
Current Status: At the end of March we estimated that there were 134 elk in the herd. During the second quarter of 2009 we had experienced 3 verified mortalities (all 3 by wolves) before the start of calving season, resulting in 131 elk at the end of the 2008/2009 ELK YEAR (an ELK YEAR ends at the start of the next calving season). Since calving season started May 20th we’ve also had 8 calves die and one yearling bull hit on Highway 77. We have also had about 40 calves born. Extrapolating these losses proportionately, and considering productivity this calving season, results in a net population estimate of 153 elk. Balancing losses with additional collared animals, we currently have 81 elk with functioning radio collars.
Elk Calving Season: The results of the 2008 calving season demonstrated the importance of the timing of green up on calf development and survival. This year we monitored the progression of spring “green up”. The snow left the Clam Lake area by mid March (earlier than normal), and ice was off area lakes by mid April. By May 5th ditches were 40-50% green, by May 8th they were 70%+ green. Aspens started leaf out on May 11th and maples on May 12th.
We began daily monitoring of potential mothers on May 18th, but were distracted by mortality signals on both the 18th and 19th. The first day of full cow monitoring was May 20th and the first day of searching was May 21st, when we found our first calf. M266 was estimated 1 day old so the new Elk Year of 2009/2010 began May 20, 2009.
From May 21st to June 9th we found 20 calves, 7 females, 12 males and 1 unknown (the bear only left a few pieces of rib and some hair). The observed sex ratio is 17 males to 10 females (171 males: 100 females). Because we lost 3 pregnant cows prior to calving we had to adjust our estimated number of calves born down to 39 calves. During calving season we lost 8 of the 20 calves found, 4 due to bears, 3 due to unknown causes and 1 due to a natural accident. The extrapolated observed loss of 40 percent resulted in an estimated loss of 16 of those 39 calves born, or 23 living calves as of June 24, 2009. No doubt we’ll lose more during the next 11 months.
In addition to elk project and DNR staff (including a crew from the BWM CO), 151 volunteer searchers from the Rocky Mountain Elk Foundation, Natural Resources Foundation, Glidden and Hayward High Schools, the Fox River Environmental Academy, and various Elk supporters, local and from around the state, helped search for elk calves. Credit goes to the many helpers who gave their time, in some cases traveling hundreds of miles, to help find calves.
Elk Health: This quarter we had verified losses of 12 elk (3 wolves, 4 bears, 1 vehicle, 1 accident, 3 unknown). The previous high quarterly observed loss was 9 during the first quarter of 2005. On May 11 we received a mortality signal for F175. It had been killed and eaten by wolves. There were no remains suitable for collection except the radio collar. F175 was 4 years old and there was a 92% probability that she had been pregnant. On May 18 we received a mortality signal for F145. It too had been killed and eaten by wolves. The kill site was 2 miles east of F175’s kill site. F145 was 5 years old and there was also a 92% probability that she had been pregnant. Similar circumstances to F175. On May 19 we received a mortality signal for F125. Again, she had been killed by wolves, and again her kill site was 2 miles east of F145’s kill, she was 7 years old and 92% probability that she had been pregnant. It’s apparent that a wolf pack, probably the Ghost Lake Pack, has learned that pregnant cows are vulnerable during these last stages of pregnancy. All 3 animals had been with groups of cows only a day or 2 before being killed, so it is likely these groups were being test
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