2 Apr 2010, 4:06pm
Predators Wildlife Management Wildlife Policy
by admin

Idaho Wildlife Services Wolf Activity Report 2009

U.S. Department of Agriculture
Animal and Plant Health Inspection Service
Wildlife Services


Full text [here]

Selected excerpts:


This report summarizes Idaho Wildlife Services’ (WS) responses to reported gray wolf depredations and other wolf-related activities conducted during Fiscal Year (FY) 2009 (October 1, 2008 – September 30, 2009) pursuant to Permit No. TE-081376-12, issued by the U.S. Fish and Wildlife Service (FWS) June 16, 2006. This permit allows WS to implement control actions for wolves suspected to be involved in livestock depredations and to capture non-depredating wolves for collaring and re-collaring with radio transmitters as part of ongoing wolf monitoring and management efforts. …


Brief summaries that pertain to those investigations which resulted in a finding of confirmed or probable wolf damage are available on request from the ID WS State Office.
Investigations Summary: WS conducted 226 depredation investigations related to wolf complaints in FY 2009 (as compared to 186 in 2008, an increase of almost 22%). Of those 226 investigations, 160 (~71%) involved confirmed depredations, 43 (~19%) involved probable depredations, 16 (~7%) were possible/unknown wolf depredations and 7 (~3%) of the complaints were due to causes other than wolves.

Based on Idaho WS investigations, the minimum number of confirmed and probable livestock depredations due to wolves in FY 2009 was:

76 calves (killed), 7 calves (injured)
14 cows (killed)
344 sheep (killed), 20 sheep (injured)
16 dogs (killed), 8 dogs (injured)
1 foal (killed), 1 goat (killed)

26 calves (killed), 3 calves (injured)
1 cow (killed)
156 sheep (killed)
4 dogs (killed), 2 dogs (injured)
1 goat (killed)

The number of both cattle and sheep killed and injured by wolves in FY 2009 was the highest ever recorded. The number of cattle killed and injured was only slightly higher than in FY 2008, but there was a dramatic increase in the number of sheep killed and injured, as compared to FY 2008 (Figure 2). Although there were more incidents of wolf predation on cattle than on sheep (Figure 3), the tendency for wolves to kill multiple sheep per incident contributed to the greater numbers of sheep killed. Wolf depredations on cattle and calves more often involve attacks on just a single animal per incident.

There were more depredation incidents involving cattle than sheep for the fifth year in a row (Figure 3), probably because of the greater exposure of cattle to wolves. In 2009, there were about 10 times as many cattle in Idaho as there were sheep (NASS 2009), and many wolves have at least some access to cattle all year, whereas most sheep are only in occupied wolf areas for 5-6 months of the year.

When wolves commit depredations on livestock, the appropriate IDFG Regional Supervisor typically authorizes WS to initiate some form of incremental lethal control to help resolve the depredation activity. Nonlethal control measures may also be implemented or recommended depending on the specific circumstances, but in many cases, particularly with sheep producers, wolf predation has occurred in spite of ongoing nonlethal efforts to prevent wolf depredations. During wolf control actions initiated in FY 2009, 12 wolves were captured, collared and released on site (as compared to 10 in FY 2008 and 9 in FY 2007) and 107 were killed (as compared to 82 killed in FY 2008 and 48 killed in FY 2007 (Figure 4)).

For the first time since wolves were reintroduced, wolves from Montana (MT) were confirmed to have killed livestock in Idaho and returned back across the State line. Also for the first time, members of an Idaho wolf pack that had been killing livestock in Idaho were taken by ID WS on the MT side of the border. In coordination with staff from MT WS and MT Fish Wildlife & Parks, a total of 12 wolves were taken by ID WS on the MT side of the border, 5 from the Sage Creek (MT) pack, and 7 from the Middle Creek (ID) pack. These 12 wolves are included in the 107 total wolves killed by ID WS in FY 09. IDFG and MTFWP record wolf mortalities based on where the wolves denned (if known).

From October 1, 2008 – May 3, 2009 (the period when wolves were a listed species), WS killed 30 wolves during control actions. From May 4 – September 30 (when wolves in Idaho were not protected by the Endangered Species Act), ID WS killed 77 wolves during control actions. None of the 107 wolves killed by ID WS in control actions during FY 2009 were north of I-90 where they were listed as endangered until May 4, 2009. …


WS conducted 226 wolf-related investigations in Idaho during FY 2009, compared to 186 investigations during FY 2008 (~22% increase from FY 2008). WS spent approximately $517,000 of appropriated and cooperative funds responding to complaints of reported wolf predation, conducting control and management actions, (salary and benefits, vehicle usage, travel and supplies) and for other wolf-related costs (equipment and supply purchases, meeting attendance, etc). Of the 226 reported wolf depredation investigations conducted in FY 2009, 160 (~71%) involved confirmed wolf predation. The control actions that followed confirmed depredations involved the lethal removal of 107 wolves (compared to 82 in FY 2008) and the radio-collaring and release of 12 wolves. The slight drop (~2%) in the amount of funds spent in FY 2009 compared to the FY 2008 level, despite the increase in wolf depredations, is most likely related to an increase in operational efficiency experienced after the delisting of wolves in May. …

Collinge (2008) compared reported numbers of livestock killed by wolves and other predators with the estimated statewide populations of the four species (coyotes, wolves, mountain lions and black bears) most often implicated in predation on livestock in Idaho. By determining the average number of livestock killed per each individual predator on the landscape, and comparing these figures among the four species, it turns out that individual wolves in Idaho are about 170 times more likely to kill cattle than are individual coyotes or black bears. Individual wolves were determined to be about 21 times more likely to kill cattle than were individual mountain lions. These comparisons highlight the importance of being able to implement effective wolf damage management procedures. …

It is probably too soon to make inferences about what effect, if any, Idaho’s sport harvest of wolves may have on future wolf depredations on livestock. However, based on an initial review of wolf harvest data, it appears likely that a number of the wolves taken by hunters during the 2009-2010 Idaho wolf season were wolves previously implicated in livestock depredations. Part of the rationale employed in the establishment of quotas for the 12 Wolf Zones was to reduce the number of wolves in areas where the most wolf depredations on livestock occur. Twenty-nine percent of ID WS’ total wolf take for FY 2009 occurred in the first two wolf zones to reach their established quotas (McCall-Weiser and Upper Snake). WS removed 22 wolves in The Southern Mountains Zone in response to confirmed depredations, and wolf hunters in the Southern Mountains Zone reached the quota of 10 wolves just after the new year began. Allowing a higher quota of wolves to be taken in these 3 zones during the 2010-2011 hunting season (if one occurs) might help contribute to a reduction in wolf/livestock conflicts, and a reduction in the need for WS to remove wolves in these zones. Alternatively, WS recommends consideration of procedures to allow for hunter harvest of wolves in localized problem areas even after a quota has been reached in a particular wolf management zone, similar to the “depredation hunts” which are often held on short notice to address specific deer or elk damage problems. Because the primary focus of these hunts would be to resolve damage, they should be in addition to, rather than instead of, WS efforts to resolve a specific wolf damage problem.

WS removed 28 wolves in the Sawtooth Zone, more than in any other wolf management zone. At the time this report is being prepared, about one third of the wolf quota in this zone has gone unfilled. No quota modifications are recommended for this or the other 8 zones not mentioned above for the 2010-2011 wolf season.

Hunting from the ground is not the most effective way to take wolves, and as shown in Figure 9., WS employees take fewer wolves by this method than any other method used. After wolves have been exposed to hunting by the public, it would seem likely that wolves will become even more difficult to hunt as they become more wary of humans. Winter harvest levels of 28-47% are sustainable in wolf populations (Mech 2001), but based on WS experience and information regarding wolf harvest in Alaska (where most wolves are taken by trapping and snaring, rather than hunting), we believe it is highly unlikely that hunting alone could be used to accomplish that level of removal in Idaho. …

Given the continually increasing number of wolf depredations on livestock in Idaho, it will be difficult for the Idaho WS program to continue the same level of responsiveness to wolf damage complaints unless changes occur. One change, which would seem unlikely in the current economic climate, would be obtaining additional resources to supplement the WS workforce in order to meet the increasing demand for service. Another option, which is more likely achievable, would be for Idaho wolf managers to exercise more of the flexibility allowed under current management guidelines to reduce the number of wolves and problem packs to a more manageable level. The Idaho Fish and Game Commission has recommended managing Idaho’s wolf population at a biologically sustainable level of about 500 animals, rather than the current 800-900 level in Idaho. The data in Figure 10. suggest that if Idaho’s wolf population could be maintained at around 500 wolves, WS’ wolf-related expenditures would be about half what they were in FY 09.

In 2008, the Idaho Fish and Game Commission directed the IDFG “To develop and aggressively utilize all available tools and methods to control wolf-caused depredation of domestic livestock.” The strategy being implemented in Wyoming for wolf damage management is an example of actions which might approach the charge given by the Idaho Fish and Game Commission. Three years ago, wolf managers in the State of Wyoming began implementing a very aggressive approach to deal with depredating wolves. Instead of continuing with an extended incremental removal approach, which was deemed inefficient and not as effective, the decision was made to move toward a much more aggressive incremental removal. When previously identified chronic depredating packs began preying on livestock, those packs were targeted for removal soon after depredations began again by those packs. In the first year of this approach (2007), confirmed wolf depredations on livestock were reduced >55% compared to the previous year (Jimenez et al. 2008), and depredations in 2008 were likewise reduced significantly from 2006 levels (Jimenez et al. 2009).

Of the estimated 97 wolf packs in Idaho in FY 2009, WS was able to verify that at least 40 of them were involved in livestock depredations. Twenty-three of the packs were involved in at least 3 depredations each and were responsible for over 67% of the total cattle losses and 76% of the total sheep losses. These 23 packs were involved in at least 151 livestock depredations (~76% of the all the verified wolf depredations in Idaho in FY 2009). WS lethally removed 74 wolves, ~75% of the total take by WS, in response to the depredations caused by these 23 packs. Employing the approach used in Wyoming for the last 3 years on at least the worst, if not most, of the remaining chronic depredating packs from 2009 would be consistent with the direction expressed by the Idaho Fish and Game Commission. Wolf removal efforts in Idaho are often more challenging and difficult than they are in Wyoming, because most of Wyoming’s depredating wolves can be effectively taken through aerial hunting, whereas a greater proportion of Idaho’s wolf problems must be addressed through ground control efforts. A combination of much more aggressive depredation control actions and liberal public hunting and trapping seasons will likely be needed to realistically achieve the Idaho Fish and Game Commission goal of managing for a population of around 500 wolves.

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