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Z YG. 66:/F/ Trends and Management of Wolf-—Livestock Conflicts in Minnesota Technical Report Series U.S. Fish and Wildlife Service The Fish and Wildlife Service publishes five technical report series. Manuscripts are accepted from Service employees or contractors, students or faculty associated with Cooperative Research Units, and other persons whose wo” is sponsored by the Service. Manuscripts are received with the understanding that they are unpublished. Most manuscripts receive anonymous peer review. The final decision to publish lies with the editor. _ Series Descriptions Editorial Staff North American Fauna MANAGING EDITOR Monographs of long-term or basic research on faunal Paul A. Opler and floral life histories, distributions, population dynamics, and taxonomy, and on community ecology. WILDLIFE EDITOR Fish and Wildlife Research Elizabeth D. Rockwell Scientific papers of scholarly qualit~ on original research, theoretical! presentations, ‘...d interpretive lit- FISHERIES EDITOR erature reviews. James R. Zuboy Biological Report Technical papers about applied research of a more PUBLICATIONS MANAGEMENT limited scope than papers in Fish and Wildlife Re- Thomas J. Cortese search. Subjects include new information arising from more comprehensive studies, surveys and inventories, TECHNICAL EDITORS effects of land use on fish and wildlife, diseases of fish Deborah K. Harris, Senior Editor and wildlife, animal control, and developments in Jerry D. Cox technology. Proceedings of technical conferences and Jamise G. Liddell symposia may be published in this series. John S. Ramsey Resource Publication Vesuas, fee sanee Graceesser Semitechnical and nonexperimental technical topics Co ; y= rotnene including surveys; data, status, and historical reports; astanee 50. handbooks; checklists; manuals; annotated bibli- EDITORIAL ASSISTANT _, _o graphies; and workshop papers. Amy D. Trujillo vin ene Waeye Leute | Summaries of technical information for readers of non- technical or semitechnical material. Subjects include topics of current interest, results of inventories and surveys, management techniques, and descriptions of imported fish and wildlife and their diseases. ISSN 0163-4801 This publication may be cited as: Fritts, Steven H., William J. Paul, L. David Mech, and David P. Scott. 1992. Trends and Management of Wolf-Livestock Conflicts in Minnesota. U.S. Fish and Wildlife Service, Resource Publication 181. 27 pp. Trends and Management of Wolf—Livestock Conflicts in Minnesota By Steven H. Fritts William J. Paul L. David Mech David P. Scott UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE Resource Publication 181 Washington, D.C. « 1992 BLANK PAGE Contents Page eva ew ee 44655556544 ne aO 4 Ob 44 Eons ed bee SESS 1 Study Area .......... soup ee ea eeeeeese esose ewsnseueseese n 4 Livestock Production in the Wolf Range ....................... 4 Methods and Program Approach ......................-.22--- 5 Data Analysis .......0.. cc c.ec.e e.ee .ee .eee. eee. ee.e ee es 7 Depredations ........c.cc .eee. ee.e e.ee .ee. ee.e e2ee .ee e 7 Annual Variation and Long-term Trend ................... 10 Seasonality of Depredations ...........................-- 12 Distribution of Depredations ............ eaten err eres i4 Role of Animal Husbandry ........ Sesh eb abs aes saves es 4 14 Program Results and Effectiveness of Control Measures ....... 16 Noncapture Methods .....4..0.2..2 .ec. eee. ese. ee.e ee es 20 Conclusion and Management Recommendations .......... ere 21 Implications for Areas Outside Minnesota ..................... 22 Acknowledgments ......... 2... 2... c cece eee cece cece eeeees 23 References ..... 0.0.0.0... ccc eee ee ee eee eee eee eees 23 ED cp 606-405-004 66-00-65 440545645464446050%48440405060504 26 ili BLANC PAG [/ Trends and Management of Wolf—Livestock Conflicts in Minnesota by Steven H. Fritts’ U.S. Fish and Wildlife Service Patuxent Wildlife Research Center Laurel, Maryland 20708 William J. Paul U.S. Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control 717 NE. Fourth Street Grand Rapids, Minnesota 55744 L. David Mech? and David P. Scott* U.S. Fish and Wildlife Service Patuxent Wildlife Research Center Laurel, Maryland 20708 Abstract. The nature and extent of wolf—livestock conflicts in Minnesota during 1975-86 was studied as part of a wolf depredation control program. The level of wolf (Canis lupus) depredation on livestock in Minnesota, as determined from the total number of complaints verified annually during 1975—86, showed a slight upward trend but did not increase significantly. A significant portion of the annual variation in verified complaints—perhaps the best index on severity of the depredation problem— was explained by variation in severity of the winter before the depredation season (inverse relation). The addition of a time variable did not account for a significant portion of the remaining variation. Verified complaints of depredations averaged 30 per year, affecting an average of 21 farms (0.33% of producers) annually. Conflicts were highly seasonal and involved primarily cattle (mainly calves), sheep, and domestic turkeys. Annual variation in losses of sheep and turkeys was higher than for cattle. In recent years, sheep and turkey losses in two northwestern counties have increased; preventive control may be warranted in those areas. Site-specific trapping and removal of wolves in response to depredations was the primary control method, resulting in Present address: U.S. Fish and Wildlife Service, Feders) ‘Present address: Ohio Division of Wildlife, Olentangy Wild- Building, 301 South Park, Helena, Mont. 59626. life Experiment Station, 8589 Horseshoe Road, Ashley, Ohio Present address: North Central Forest Experiment Station, 43003. 1992 Folwell Avenue, St. Paul, Minn. 55108. 2 RESOURCE PUBLICATION 181 captures of 437 wolves in 12 depredation seasons. For the wolf range as a whole, no relation was found between wolf removal and subsequent depredation rates; however, wolf removal seemed to reduce depredations locally at some farms. When adults and yearlings were removed, no subsequent lusses occurred in about 55% «* instances; removal! of young of the year reduced losses in 22%. Removal of breeding wolves did not reduce the incidence of subsequent losses more than removal of nonbreeding adults and yearlings did. The low number of conflicts for 1975-86 was remarkable considering the frequent contact between wolves and livestock. However, an update of complaints for 1987-89 revealed a definite upward trend in depredations (Epilogue). Improvements in farm management practices may reduce the present number of conflicts. Key words: Canis lupus, control, control program, depredation, domestic animal, endangered species, livestock, recovery, wolf. Wherever gray wolves (Canis lupus) and do- older. Some wolves disperse from their packs to mestic animals have coexisted in North America, become lone wolves that search for a mate and an some depredation has occurred (Young and area for establishing their own packs. Large ungu- Goldman 1944; Fritts and Mech 1981; Fritts 1982; lates are the main prey of wolves wherever they Brown 1983; Gunson 1983; Tompa 1983a; Fritts have been studied in North America (Mech 1970; and Paul 1989). This problem, although as old as Carbyn 1987). animal domestication itself, has only recently In the contiguous United States, the wolf is become the subject of scientific scrutiny; however, found mainly in northern Minnesota where the documented information on this aspect of wolf biol- population numbers about 1,200 (USFWS 1978; ogy is scarce. As was true historically in the United Berg and Kuehn 1982). The animal is i‘sted by States and Canada, depredation on livestock is the U.S. Fish and Wildlife Service (Sei vice) as not only a major challenge to human tolerance of threatened in Minnesota (43 Federal Register ‘612, the wolf where wilderness and agriculture meet, 9 March 1978) and endangered elsewh= .. The but also to recovery of wolves in such areas as wolf presently shows some natural range . <pan- northern Wisconsin and Michigan, the northern sion into other states, recolonizing northern Wis- Rocky Mountains, parts of the Southwest, and consin (Mech and Nowak 1981; Thiel and Welch upstate New York (U.S. Fish and Wildlife Service 1981); Michigan (Robinson and Smith 1977; Thiel [USFWS] 1978, USFWS 1982; Henshaw 1982; 1988; Thiel and Hammill 1988), extreme north- USFWS 1987). western Montana (Boyd 1982; Ream and Mattson Wolves live in packs or family groups that, in 1982; Ream et al. 1985; Ream et al. 1991), Minnesota in midwinter, average from three to and possibly Idaho (Kaminski and Boss 1981; eight individuals and occupy territories of 110 to Kaminski and Hansen 1984). Some recent activ- 260 km? (Mech 1973, 1986; Van Ballenberghe et ity is suspien cthet Ceascdade s Ranogf Weash - al. 1975; Fritts and Mech 1981; Berg and Kuehn ington (Laufer and Jenkins 1$89). However, only 1982; Fuller 1989). Packs typically consist of an in Minnesota has substantial experience been ob- adult male, adult female, and their offspring from tained in managing wolf—human conflicts during one or more generations. A dominance hierarchy recent times and under the Endangered Species exists within packs, with breeding animals usu- Act of 1973. ally being the dominant members. The dominant Wolves kill livestock and other domestic ani- male and female guide almost all the pack’s activi- mals in northern Minnesota (Fritts and Mech ties. In Minnesota, except for rare occurrences, 1981; Fritts 1982; Mech et al. 1988b; Fritts and only one female within each pack breeds; litters of Paul 1989). These depredations are of concern not 5-6 pups are born in early April to early Mav. only to the Service, but to the Minnesota Depart- Pvps are adult-sized by winter, but usually stay ments of Natural Resources (MDNR) end Agricul- v..th their packs until they are 1-2 years old or ture (MDA), and to the U.S. Department of Agri- WOoLF-LIVESTOCK CONFLICTS IN MINNESOTA 3 culture (USDA), to which animal damage controi tions on domestic animals, except in Wolf Manage- responsibility was transferred in March 1986. ment Zone 1 in extreme northeastern M:nnesota, Moreover, the nature and extent of wolf—livestock an established sanctuary (USFW. 1978; Fig. 1a). conflicts in Minnesota is closely monitored by The primary source of information about wolf advocates and opponents of wolf recovery in other depredations in Minnesota; including a program parts of the United States, particularly the north- description for dealing with the problem (Fritts ern Rocky Mountains and the Southwest. Severa! 1982), is based on data obtained from 1975 through types of livestock are available to wolves in Min- 1980, but focused on information from 1979 and nesota. Our experience with active depredations 1980. With more recent data obtained we are able in the state may lend insight into problems and to (1) describe the wolf depredation problem in solutions that may occur where wolves become Minnesota more thoroughly than was previously established naturally or by reintroduction, and possible, (2) evaluate the effectiveness of control can provide background for developing effective methods used, and (3) reevaluate the conclusions control programs in those areas. of the earlier report (Fritts 1982). For the present Programs for controlling wolf depredations in report we analyzed data from 1975 through 1986, Minnesota have been described and the results the years from the listing of the wolf as threat- provided (Fritts 1982; Fritts et al. 1984). Since ened in Minnesota and the initiation of a federal 1978, the threatened status of the wolf in Minne- control program to the transfer of the depredation sota has allowed state and federal authorities to control program from the Service to the USDA in kill wolves proven to have committed depreda- 1986. The Epilogue contains an update for 1987-89. | 100 Km | | | | Fig. 1.4. Wolf Management Zones in Minnesota. Two counties where depredations were relatively high in Zene 5 are also shown. Zones 1, 2, and 3 are critical habitat. 6. Occupied and potential wolf range in Minnesota. A = primary, B = Roseau peripheral, C = northwest nonoccupied, D = Marshall peripheral, E = Hubbard disjunct, F = central nonoccupied, G = Crow Wing disjunct, H = main peripheral, / = Nemadji disjunct. Blank areas indicate intensively farmed or deveioped areas devoid of resident wolves (Mech et al. 1988a). RESOURCE PUBLICATION 181 Study Area all population seemed to be generally stable, with essentially all habitat filled, our observations sug- A general description of the 59,900 km” wolf gested that some increase may have occurred in range in Minnesota (Mech et al. 1988a) is pro- the western part of the range, especially in Wolf vided (USFWS 1978; Fig. 1b). Generally, the area Management Zone 5 (Fig. la). The total Minne- can be charaacs otne eof srhorit gzroweingd se a- sota population was estimated at 1,000-1,200 in son, rocky outcrops, muskeg, infertile soil, and the mid-1970's (USFWS 1978) and at 1 235 in 1979 low human density. Topography and vegetation (‘Berg and Kuehn 1982). Some statewide increase vary from the eastern to western part of the area. since 1979 is likely. In northeastern Minnesota the terrain is gently Wolves occasionally prey on Minnesota live- to strongly rolling with frequent rock outcrops. stock wherever the two coexist, but most depreda- Farther west and southwest the terrain is flatter, tions occur in north-central and northwestern forest cover is less consistent, and soils range from counties where farm density and livestock produc- peat to sand and sandy loam with a broad range of tion is highest within the wolf's range. Fritts textures. Climate is cool—temperate (Hovde 1941) (1982) estimated that there were about i2,230 with snow cover from about mid-November to mid- farms (at least 80% having some livestock) in the April. Mean January temperature at Grand Rap- wolf range in 1979, containing 234,000 cattle, ids, near the center of the area, is -14°C; the July 91,000 sheep, and an unknown number of turkeys, mean is 19°C (U.S. Department of Commerce, swine, horses, goats, chickens, ducks, and geese. unpublished data). Precipitation at that reporting Recalculation of the number of farms based on station averages 67 cm. more recent census data (1982 v. 1976; Minnesota Uplad forests in the region are mixed conif- Agricultural Statistics 1984) sho. +d about 7,200 erous—deciduous. Infertile soils and poor drainage farms. This figure is lower than the previous one limit agriculture in much of the primary range of hecause a more restricted wolf range was used in wolves. Lakes are common. About 77% of the pri- computations of farm numbers—based on a refine- mary range is classified as forested land use, ment of the known wolf distribution (Mech et al. whereas forested in the other portions of the range 1988a); and a real decline occurred in farm num- varies between 21 and 86% (G. L. Radde, personal bers in wolf range—-estimated at 13% from 1976 communication). Human population in the pri- to 1982. A further decline in farm numbers from 7,200 to 6,800 was ré@vealed by the 1987 census mary zone declined from 1970 to 1986, while it data, but total land aréa in farms declined only increased in each of the other zones where farm 1%. Farm size averaged [41.6 ha in the wolf range density is higher. White-tailed deer (Odocoileus virginianus) during the study, tending+ o be larger in north- are the primary prey of wolves in all occupied western counties and smaller in northeastern counties. . areas of Minnesota, but wolves also eat moose (Alces alces), beaver (Castor canadensis), and snowshoe hares (Lepus americanus; Frenzel 1974; Van Ballenberghe et al. 1975; Fritts and Mech Livestock Production in the 1981; Fuller 1989). In our studies, deer popula- Wolf Range tions seemed to be at least as high in areas where livestock were produced as in more remote forested areas. Reliable estimates of deer populations The northern Minnesota wolf range is not a have been available for the wolf-inhabited creas major livestock production area compared with of Minnesota since 1982, and they showed no sub- oth.¢ areas of the state. Cattle, sheep, and tur- stantial changes during 1982-86. However, keys constituted the domestic prey most available decreases of 8 to 24% were indicated in some deer to wolves from 1975 through 1986, and produc- management subunits in the southern and south- tion of cattle and sheep generally declined during western part of the wolf range where several of the period. Cattle were fairly common across the the farms are located (Joselyn et al. 1988). area, varying between 231,000 and 362,000 dur- No data were available on wolf population ing the period (midsummer estimates based on trends in the main agricultural areas of Minne- data from Minnesota Agricultural Statistics 1975- sota during the present study. Although the over- 82, 1984—87; Fig. 2). Although both beef and dairy