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Conserving the Nature of America

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people.

This monitoring plan was prepared in concert with the February 8, 2007, Final Rule to delist the the Western Great Lakes DPS. That Final Rule was overturned and gray wolves in the Western Great Lakes states revert to protection under the ESA. go to the Timeline of Federal Actions for more information.



Post-Delisting Monitoring Plan for the
Western Great Lakes Distinct Population Segment of the Gray Wolf (Final)


PDF version



Section 4(g) of the Endangered Species Act (Act) requires the Service to monitor, for a minimum of five years, any species that is delisted due to its recovery.  The intent of this monitoring is to determine whether the species should be proposed for relisting under the normal listing procedures, relisted under the emergency listing authority of the Act, or kept off of the list because it remains neither threatened nor endangered.For the Western Great Lakes Distinct Population Segment of the Gray Wolf [WGLDPS, 71 Federal Register 15266; (March 27, 2006); Figure 1], the post-delisting monitoring (PDM) plan should focus on reviewing and evaluating (1) population characteristics of the distinct population segment (DPS), (2) threats to the DPS, and (3) implementation of legal and management commitments that are important in reducing threats to the DPS or maintaining threats at sufficiently low levels as these have a bearing on the five factors set forth in the Act.


For the delisted WGLDPS, focusing PDM on these three aspects is necessary and sufficient to ensure that the DPS does not decrease to the point of again meeting the definition of threatened or endangered without an appropriate and timely response from the Service.  Winter and late-winter estimates of wolf populations in Minnesota, Wisconsin, and Michigan have demonstrated that wolves in the WGLDPS have surpassed their numerical recovery criteria for a sufficient period due to a reduction in threats over the last 25 years [U.S. Fish and Wildlife Service (USFWS) 1992].  The protection and management of wolves by states will be critical in conserving the WGLDPS.  In addition, management of wolf habitat by tribes and federal land management agencies will continue to be important in conserving the WGLDPS.  Since delisting, state and tribal laws and regulations have become the primary mechanism to protect wolves from their primary former threat – excessive human-caused mortality.


PDM for the WGLDPS will be focused within the borders of Minnesota, Wisconsin, and the Upper Peninsula (UP) of Michigan, where wolf populations have attained the numerical recovery criteria specified in the Recovery Plan for the Eastern Timber Wolf (USFWS 1992).  The delisting of the WGLDPS of the Gray Wolf is based on wolf recovery in those three states.  Therefore, it is not necessary to conduct intensive monitoring in other parts of the DPS.  The Service is interested, however, in reviewing any data regarding the existence of individual wolves or wolf populations outside of the core recovery areas (Fig. 1), especially in the Northern Lower Peninsula (NLP) of Michigan.  Additionally, the Service is interested in obtaining disease and parasite data from wolves found in other portions of the DPS that may suggest a new or increasing threat that may impact wolves in the core recovery areas.


Map gray wolf western Great Lakes DPS.


Public Review and Comment

On June 4, 2007, the Service announced the availability of its draft plan to monitor the WGLDPS of the Gray Wolf for public review and comment.  After the comment period closed on July 5, 2007, the Service reviewed each comment received and prepared comments in response to any substantive comments (see Appendix).


Monitoring by the States

The States of Minnesota, Wisconsin, and Michigan have carried out wolf monitoring for several decades, with significant assistance from numerous partners, including the U.S. Forest Service, National Park Service, U.S. Department of Agriculture (USDA)-Wildlife Services, tribal natural resource agencies, and the Service.  In Minnesota, for example, these agencies provide data directly to the Minnesota Department of Natural Resources to support its development of statewide population estimates (Erb and Benson 2004).  The methods used in this monitoring are summarized below, and are described in detail by Erb and Benson (2004), Wydeven et al. (2006), and Potvin et al. (2005).


All three states intend to implement monitoring methodologies that would allow for comparison to data obtained before delisting.  As specified in the Recovery Plan for the Eastern Timber Wolf (USFWS 1992), population monitoring will be conducted during the late winter months when wolf populations are at the low point of their annual cycle and when snow cover and lack of foliage on deciduous trees facilitates tracking and aerial counting.  


Table 1.  Gray wolf winter populations in Minnesota, Wisconsin, and Michigan (excluding Isle Royale) from 1976 through 2006.




Wisconsin (WI)

Michigan (MI)

WI & MI Total












1,500 & 1,750
































































































Minnesota Department of Natural Resources (DNR) will continue to use a rangewide survey/local intensive study approach, which is suitable for a wolf population of thousands of animals ranging across more than 34,100 square miles (88,325 square kilometer).  The most recent survey was conducted during the winter of 2003-2004 and provided a population estimate used in making the Service’s delisting decision.  The Minnesota Wolf Management Plan (Minnesota DNR 2001) specifies that the survey frequency will be increased from the previous 9-10-year interval.  Statewide wolf population and distribution estimates will be conducted during the first and fifth years after delisting and subsequently at 5-year intervals. 


During the years between statewide population estimates, the DNR will collect and analyze data from its predator scent post survey, furbearer winter track survey, and recorded wolf depredations of domestic animals.  Each of these will furnish independent annual indices of wolf population trends and occupied rangebut will not provide population estimates.  In the “Forest Zone”, which comprises the main portion of the wolf range in Minnesota, there were 173 scent station routes completed in 2006 (Erb 2006).  Each route is 2.7 miles long and contains ten scent stations.  Data from these indices must be interpreted with caution and may not by themselves be reliable indicators of population declines.  Since 1994, however, trends in these indices point to a stable or slowing growing wolf population in Minnesota, consistent with the results of the statewide population estimates [72 Federal Register 6054 (8 February 2007)].


To estimate statewide wolf abundance, Minnesota uses estimates of winter pack territory and pack size that are based on radio telemetry studies in different portions of Minnesota wolf range.  The extent of occupied wolf range is determined based on an extensive survey of hundreds of tribal, federal, state and other natural resource managers, wildlife biologists, conservation officers, and other knowledgeable field personnel, and also by using human density and road density criteria (Erb and Benson 2004).  Wolf density data from the localized radio telemetry studies are applied to theestimated wolf range to derive an estimate of the numbers of wolves in packs in Minnesota.  This number is adjusted upward to account for non-pack wolves and a 90 percent confidence interval for the resulting point estimate is calculated (Erb and Benson 2004).  Using those methods for the winter of 2003/2004, Minnesota DNR estimated 3,020 wolves in the state with a 90 percent confidence interval ranging from 2,301-3,708 (Erb and Benson 2004).


In addition to reviewing each statewide wolf population estimate and wolf population indices, the Service will request from Minnesota DNR an annual summary of recorded wolf mortality incidents.  In the years between statewide population estimates, these mortality data will provide an additional index to the wolf population in the state and may help to assess the relative importance of various mortality factors.



Wisconsin DNR will continue its intensive radio-tracking and annual winter track and sign surveys to provide data directly comparable to those available for recent years.  Wisconsin’s methods are based on weekly aerial radio-tracking of about 40 percent of Wisconsin wolf packs from mid- through late-winter, supplemented by multiple winter track and sign surveys conducted in all areas suspected of containing wolf packs.  Those complementary methods identify the locations and approximate territories of nearly all packs and have a high likelihood of detecting most or all members of each pack.  Detection probability is less than 100 percent.  Therefore, the method probably underestimates the number of wolves in packs.


In several years, packs have subsequently been documented where no packs were suspected.  When this occurs, WI DNR retroactively adjusts the previous year’s population estimate to account for the missed wolves.  Although there currently are no data available to derive confidence limits, the DNR’s survey methods probably underestimate packs and pack wolf numbers by less than 10 percent.  Because some of the underestimate is removed by adjustment in the subsequent year, the ultimate underestimate probably averages 5 to 10 percent or less for pack wolves.  Winters with less snow cover produce poorer conditions for track surveys and reduced contrast for aerial sightings, likely resulting in larger underestimates in those years.


A second cause of underestimation is the number of lone wolves that are not included in the final estimate.  Lone wolves are generally believed to constitute about 10-15 percent of a wolf population in winter (Fuller et al. 1992, 2003).  WI DNR recorded 2 to 13 percent of the wolf population as loners from 1991-2000, but among radio-collared wolves an average of 8 percent spent the whole winter as loners (range 0 to 15 percent, Wydeven et al. 2000).  The 2006-2007 population estimate included 17 (3%) lone wolves.  Wolf reports were received from numerous Wisconsin counties beyond the area surveyed by the DNR.  Although many of these are likely misidentifications by the public, some of these reports likely are of dispersing lone wolves not included in the annual count.  Thus, missing lone wolves may further underestimate the statewide wolf population in Wisconsin.


Due to the minimal likelihood of double-counting pack wolves and the conservative approach used to estimate numbers of lone wolves, Wisconsin’s methods are unlikely to overestimate the number of late-winter wolves in the state.  During the PDM period Wisconsin DNR might test other methods, but does not plan to replace its traditional radio tracking/snow tracking surveys (Wydeven in litt. 2006). 



Michigan DNR also plans to continue its intensive ground tracking, aerial observation, and radio telemetry-based methods during the PDM period.  Michigan's methods are very similar to those used by Wisconsin, including weekly monitoring of radio-collared wolves in about 40 percent of the packs, although Michigan does not use volunteers to assist with ground tracking.  With the assistance of USDA-Wildlife Services, Michigan DNR annually spends over 2,000 person hours conducting the ground tracking portion of the survey.  This effort involves searching over 8,000 miles of roads and trails at least once for wolf sign, with many miles searched multiple times. 


Due to the increases in wolf numbers and the corresponding increase in effort required to count wolves, Michigan DNR is planning to implement a sampling approach to more efficiently determine wolf abundance (Potvin et al. 2005).  Under this approach, Michigan DNR would stratify the UP into three sampling areas and intensively survey about 40-50 percent of the wolf habitat area annually.  This stratified sampling approach would produce unbiased and precise estimates of the total wolf population that may be compared statistically to estimates derived before delisting (Beyer in litt. 2006, Lederle in litt. 2006). 


Summary of Monitoring in Wisconsin and Michigan

The late winter surveys by the Wisconsin and Michigan DNRs produce estimates of their wolf populations at the low points in their annual cycle.  By late winter, mortality factors such as starvation and hypothermia, perhaps exacerbated by mange and other diseases, have largely exerted their effects and the annual production of pups has not yet begun.  In early spring after pups are born it is likely that the wolf population approximately doubles the late-winter population.  Therefore, the late-winter population estimates must always be accompanied with this understanding when used to evaluate recovery progress and post-delisting viability – they are minimum estimates of the wolf population made at its annual low point. 


Monitoring of Threats

The most important part of this monitoring plan is to determine, with sufficient confidence, that population levels exceed the objectives described in the recovery plan, as summarized above.  Where feasible, however, the Service should also review mortality records, diseases, prey abundance, and other information to determine whether or not significant problems for wolf populations may be developing during the post-delisting monitoring period.  Post-delisting threats are all the threats that may affect the species after the protections of the Act are removed.  These include ongoing threats whose magnitude has been reduced by conservation actions, continuing threats that have not been mitigated since listing, or new threats that are first recognized subsequent to delisting.  For purposes of this monitoring plan, we believe the most important threats to monitor are those that have been sufficiently reduced and contained, but not permanently eliminated, during the recovery process.  For gray wolves in the WGLDPS, those threats are primarily the various forms of human-caused mortality that were reduced by conservation actions before the DPS was delisted.  Additionally, a variety of known wolf diseases and parasites are of concern and new diseases represent a threat that requires vigilance.  All of these anticipated post-delisting threats are described in detail in Summary of Factors Affecting the Species in the preamble of the 2006 proposed delisting rule [75 Federal Register 15277-15302 (8 February 2007)]. 


Minnesota, Wisconsin, and Michigan DNRs will continue to compile summaries of human-caused and natural mortality and to provide this information to us annually.  This reporting will include information on: wolves killed legally and intentionally for depredation control, conservation actions taken to reduce threats, conduct research, or for other reasons, accidental mortality (e.g., vehicle collisions and incidental trapping mortalities), natural mortality (e.g., disease and intraspecific conflict), illegally killed wolves, and mortalities from unknown factors.  Although starvation may be the major cause of pup mortality, disease may also be important during some years and may also infrequently play a significant role in adult mortality.  Significant levels of mortality due to disease would be reflected in population surveys conducted by each state.  Nevertheless, each state plans to also implement some level of disease monitoring. 


The wolf management plans for Minnesota and Wisconsin commit the respective DNRs to conduct necropsies on dead wolves, carry out disease screening on live-trapped wolves, and analyze wolf scat for pathogenic microorganisms and parasites.  The Michigan DNR states that wolf health and disease monitoring will receive a high priority for a minimum of five years after Federal delisting.  The Service will request this information annually for review (see below).


Native American Indian tribes are responsible for wolf management within their reservations.  In addition, many tribes have rights and interests in wolves in a number of treaty ceded territories. Consistent with our responsibilities to tribes and our goal to have the most comprehensive data available for our annual review, we will annually contact tribes and their designated intertribal natural resource agencies within the DPS to obtain any information they wish to share regarding wolf populations, the health of those populations, or changes in their management and protection.  Reservations within the WGLDPS that may have significant wolf data to provide during the post-delisting period include Bois Forte, Bad River, Fond du Lac, Grand Portage, Lac Courte Oreilles, Lac du Flambeau, Leech Lake, Menominee, Oneida, Red Lake, and White Earth.  The Service will annually contact the natural resource agencies of each of these reservations and that of the 1854 Treaty Authority and Great Lakes Indian Fish and Wildlife Commission to request wolf data as described below. 


We will also annually contact the federal land management agencies with significant wolf populations on their units in Minnesota, Wisconsin, and Michigan to obtain any additional data they may have regarding wolf management/protection, numbers, mortality, injuries, or disease.


Implementation of Legal and Management Commitments

The recovered WGLDPS is dependent upon wolves receiving sufficient protection in Minnesota, Wisconsin, and Michigan to ensure that a viable wolf population will remain in Minnesota and a second viable population will exist in Wisconsin-Michigan for the foreseeable future.  When the Act’s protection ended at the time of delisting, the focus of wolf protection shifted to state and tribal governments and to federal land management agencies.  Protections by the states as identified more fully in the Final Rule [72 Federal Register 6052 (8 February 2007)], may be most important because they affect the greatest number of wolves in the DPS. 


The Service has concluded that the wolf management plans of Minnesota, Wisconsin, and Michigan and the protection of gray wolves by the tribes and federal land management agencies are sufficient to conserve viable wolf populations within the DPS.  Therefore, the Service will annually evaluate the implementation and outcomes of these wolf management plans, protections, and related guidelines and procedures.


Monitoring Duration and Methods

The Service will implement this PDM plan for five years after the delisting of the Gray Wolf WGLDPS.  Therefore, we plan to complete this monitoring in 2012 – for example, population data obtained during the winter of 2011-2012 will represent the final year of monitoring.  This will allow for five complete Wisconsin-Michigan population estimates after delisting has occurred and non-federal wolf management plans and protections become operational.  Minnesota DNR will develop statewide estimates for the winters of 2007-2008 and 2011-2012.  The WGLDPS population currently is estimated to be several times greater than the numerical delisting criteria stated in the 1992 Recovery Plan (USFWS 1992 and Table 1) and we currently envision no threat or combination of threats that are reasonably likely to drive wolf numbers rapidly downward.  Therefore, we believe 5 years of PDM is sufficient.  Under the circumstances described below we will consider extending the PDM period and/or taking action to restore federal protections under the Act.


We will gather available data annually from Minnesota, Wisconsin, and Michigan DNR’s and from the Native American natural resource agencies and federal land management agencies with large land bases within occupied wolf range in these three states.  We will also contact the wildlife management agencies of the other states in the DPS to obtain any relevant data acquired during the previous year.


The Service will contact state and tribal wildlife resource conservation agencies and federal land management and research agencies to establish points of contact to obtain the relevant data annually.  Within the Service, the Endangered Species Coordinator at the Service's Twin Cities, Minnesota, Ecological Services Field Office will be the focal point for the data gathering, evaluation, and coordination with former members of the Eastern Gray Wolf Recovery Team and other experts, as appropriate.


Our data gathering will include the following, with the primary data shown in bold type:


  • Wolf population estimates, pack numbers, and estimated occupied area from Minnesota, Wisconsin, and Michigan DNRs and from reservations within the wolf-occupied portions of these three states;
  • Wolf mortality data from the three states and the reservations within occupied range in the WGLDPS;
  • Data on the occurrence of diseases and parasites in wolves throughout the WGLDPS;
  • Information on changes made within the previous year, or changes likely within the next year, to state regulatory mechanisms that change the previously-provided protections for gray wolves, gray wolf prey, or gray wolf habitat within the DPS;
  • Summary data for all law enforcement investigations relating to wolves by the three states;
  • Summary reports of wolf depredation incidents and the resolution of those incidents in the WGLDPS;
  • Reports or publications on public attitudes toward WGLDPS wolves;
  • Reports of wild gray wolves in other states within the WGLDPS;
  • Wolf research reports or publications dealing with WGLDPS wolves or factors adversely affecting them;
  • Educational materials, press releases, and other wolf-related public information/education documents distributed by the state, tribal, and federal agencies within the WGLDPS, and similar materials distributed within the WGLDPS by non-governmental agencies.


The Service will annually contact the following four categories of agencies, requesting the listed types of data.


1) Minnesota, Wisconsin, and Michigan Departments of Natural Resources:

  • population estimates, pack numbers, occupied area
  • mortality data
  • disease/parasite occurrence in wolves
  • verified or probable depredation incidents and follow-up actions
  • changes to regulatory mechanisms affecting the protection or management of the species, its prey, and its habitat
  • law enforcement investigations of wolf mortality
  • other relevant information including any recent population estimates or indices for primary wolf prey, white-tailed deer (Odocoileus virginianus)and moose (Alces alces)


2) Tribal Natural Resource Agencies in the DPS:

  • population estimates and pack numbers
  • mortality data
  • changes to management
  • other relevant information including any recent population estimates or indices for primary wolf prey, white-tailed deer (Odocoileus virginianus)and moose (Alces alces).


3) Other States within the WGLDPS – North Dakota, South Dakota, Iowa, Illinois, Indiana, and Ohio:

  • verified or probable wolf reports & disposition of any verified or probable wolves
  • disease/parasite occurrence in documented wolves
  • other relevant information


4) Federal Land Management Agencies with large land bases within occupied wolf range – Chippewa National Forest (NF), Superior NF, Chequamegon-Nicolet NF, Hiawatha NF, Ottawa NF, Voyageurs National Park; and national wildlife refuges with sufficient land base or known wolf presence:

  • population estimates and pack numbers
  • mortality data
  • law enforcement investigations of wolf mortality
  • regulatory mechanism changes
  • other relevant information including any recent population estimates or indices for primary wolf prey, white-tailed deer (Odocoileus virginianus)and moose (Alces alces).


Wisconsin and Michigan DNRs currently finalize their annual population between April and June.  Therefore, we expect to gather this information annually during that timeframe and to complete our evaluation of the information later in the year.  The data and the Service’s evaluations thereof may be provided in entirety or in summary form to the former members of the Eastern Gray Wolf Recovery Team for their independent review.  The Service may request additional reviews from other wolf experts and independent specialists, as appropriate.  We will attempt to focus these annual reviews on any indications of (1) increasing or new threats to wolf population viability, (2) a decline in wolf population or decrease in occupied range, (3) a change in state, tribal, or federal management and protection that might have adverse effects on wolf conservation.  We will also evaluate other factors that might indicate or cause a decline in wolf population viability in the WGLDPS and how these might affect the status of the species in terms of the Act’s five listing factors.  Although the Service’s review will focus on population trends, mortality data, and protection and enforcement activities, other data will be reviewed as appropriate.  We will post the results of these reviews in summary form on our Web site in a timely manner to allow interested parties to annually review our PDM and our evaluation of the data.


Events & Factors Indicating a Potential Need for Action by the Service

Although it may seem desirable to specify in advance a list of explicit quantitative triggers that would require specific actions by the Service (e.g., extension of the PDM period, initiating a formal status review, or publication of a relisting proposal), such actions should only be taken based on a more comprehensive review.  Thus, we are instead identifying three quantitative events and describing several examples of qualitative factors that would lead to our consideration of the actions (a) through (d) described below, but which would not necessarily trigger these actions.  Consultation with the former members of the Eastern Gray Wolf Recovery Team, other wolf experts, and endangered species biologists within the Service will help to identify the appropriate response.


Events that Might Cause Consideration of Relisting or Emergency Relisting

Any of the events described below might be evidence of a serious problem, but by themselves may not trigger Federal regulatory action.  The occurrence of any of the following could cause the Service to investigate the underlying cause, the likely duration of the decline, and other data relevant to wolf population viability in the WGLDPS to decide if a proposal to relist, an emergency relisting, or other action is warranted.


  • A decline that reduces thecombined Wisconsin-Michigan (excluding Isle Royale and the Lower Peninsula) late winter wolf population estimate to 200 or fewer wolves.1
  • A decline that brings either the Wisconsin or the Michigan (excluding Isle Royale and the Lower Peninsula) wolf estimate to 100 or fewer wolves.
  • A decline that brings the Minnesota winter wolf population point estimate or lower end of the 90% confidence interval to 1500 or fewer wolves.


The numeric recovery goals were 1251-1400 for Minnesota (USFWS 1992:28) and 100 for the Wisconsin-Michigan population (USFWS 1992:25).


Others Factors Indicating a Potential Cause for Concern

The Service may evaluate the potential impact of any of the following events on the conservation of the WGLDPS, but would not necessarily take additional actions. 


  • A rapid and large decline (for example, 25 percent or more from the previous year) in the late winter wolf population estimate for Wisconsin or Michigan.
  • Any wolf population decline in Wisconsin Zones 1 and 2 or the Upper Peninsula of Michigan of three years or more in duration.
  • A substantial and widespread increase in mortality from known or unknown causes.
  • Evidence of a new wolf disease or substantial increase in virulence of a previously known wolf disease, even in the absence of noticeable demographic impacts on the wolf population.
  • A substantial decline in the wolf prey base across a large portion of the occupied wolf range in the DPS.
  • A significant adverse change in wolf, wolf prey, or wolf habitat management practices or protection across a substantial portion of the occupied wolf range in the WGLDPS.


If declines in wolf abundance in the WGLDPS (as described above under ‘Events’ and ‘Other factors’) are evident following an annual PDM review, the Service may take any or all of the following actions: 


  • extend the PDM period;
  • add new components to the PDM;
  • initiate a comprehensive status review of the species within the DPS;
  • investigate or remedy the cause(s) of the decline. 


In addition, the Service may determine that none of these four actions is appropriate.  For example, no action may be necessary if the decline is relatively minor, is likely to be temporary or readily resolved, or is not statistically significant.


As part of each annual evaluation the Service will also consider changes to the PDM methodology and data review process.  If such changes are necessary to meet the Service's responsibilities under Section 4(g) of the Act, they will be promptly implemented, subject to available funding needed for their implementation.


During the monitoring period, if the Service detects a change in wolf populations or a significant increase in threats, it can evaluate and change monitoring methods or consider relisting.  At the end of the PDM period the Service will conduct a final internal review and may request reviews by the former members of the Eastern Gray Wolf Recovery Team and other independent specialists, as appropriate.  Based on those reviews, which will be posted on the Service’s Internet site, the Service will decide whether to relist, continue monitoring, or end monitoring.   


1 To calculate the total number of wolves in Michigan and Wisconsin, the Service will assume that the number of wolves in either state is equal to the lower end of the 90% confidence interval or, in the absence of any confidence intervals, the minimum value of the reported range.  As of this plan’s completion, Michigan plans to annually compute confidence intervals for its statewide population estimate, whereas Wisconsin provides a range with minimum and maximum values.


Literature Cited

Beyer, Dean.  2006.  E-mail from Beyer, MI DNR Wildlife Research, to Ron Refsnider, USFWS Regional Office, Ft. Snelling, MN, dated 08/10/06.  Subject:  Potential for "MN-style" wolf monitoring in WI and MI?  2 pp. with 6-page attachment by Drummer.


Erb, J. and S. Benson.  2004.  Distribution and abundance of wolves in Minnesota, 2003-04.  Unpublished report by Minnesota Department of Natural Resources, Grand Rapids, MN 13 pp.


Fuller, T.K., W.E. Berg, G.L. Radde, M.S. Lenarz, and G.B. Joselyn.  1992.  A history and current estimate of wolf distribution and numbers in Minnesota.  Wildlife Society Bulletin 20:42-54.


Fuller, T.K., L.D. Mech, and J.F. Cochrane.  2003.  Wolf population dynamics.  Pp. 161-191 In Wolves:  Behavior, Ecology, and Conservation.  eds. L.D. Mech and L. Boitani.  Univ. of Chicago Press, Chicago.  448 pp.


Lederle, P.  2006.  E-mail from Lederle, MI DNR Wildlife Research Section Supervisor, to Ron Refsnider, USFWS Regional Office, Ft. Snelling, MN, dated 09/05/06.  Subject:  Support for the sampling protocols.  1 p.


Michigan Department of Natural Resources.  1997.  Michigan gray wolf recovery and management plan.  Lansing, MI  58 pp.


Minnesota Department of Natural Resources.  2001.  Minnesota wolf management plan.  Prepared by the Section of Wildlife, dated February 2001.  36 pp. plus 9 appendices.


Potvin, M.J., T.D. Drummer, J.A. Vucetich, D.E. Beyer, R.O. Peterson, and J.H. Hammill.  2005. Monitoring and habitat analysis for wolves in Upper Michigan.  J. Wildl. Mgmt. 69:1660-1669.


U.S. Fish and Wildlife Service.  1992.  Recovery plan for the eastern timber wolf.  Twin Cities, MN  73 pp.

Wiedenhoeft, J.E.  2005 . Summary Report - "Minnesota-type" wolf survey for Wisconsin - GIS analysis. Unpublished report to State Wildlife Grants Program - CWCP. Wisconsin DNR, Park Falls, WI. 14 pp.


Wydeven, Adrian.  2006.  E-mail from Wydeven, WI DNR Mammalian Ecologist, to Ron Refsnider, USFWS Regional Office, Ft. Snelling, MN, dated 08/09/06.  Subject:  Potential for "MN-style" wolf monitoring in WI and MI.  2 pp. with 14-page attachment [Wiedenhoeft 2005, listed separately above]. 


Wydeven, A.P., J.E. Wiedenhoeft, B.E. Kohn, R.P. Thiel, R.N. Schultz, and S.R. Boles.  2000.  Progress report of wolf population monitoring in Wisconsin for the period October 1999 - March 2000.  Unpublished report by Wisc. Dept.  Natural Resources, Park Falls, WI.  31 pp.


Wydeven, A.P., J.E. Wiedenhoeft, R.N. Schultz, R.P. Thiel, S.R. Boles, and E. Heilhecker.  2006.  Progress report of wolf population monitoring for the period October 2005 – March 2006.  Unpublished report by WI DNR, Park Falls, WI.  39 pp.


February 2008



Gray Wolf Population Monitoring Results

Gray Wolf in the Western Great Lakes States