Wolves (Canis lupus) have expanded their distribution into areas of the midwest United States that have not had wolves for several decades.
With recolonization of wolves into agricultural areas, there is
increasing concern of wolf-livestock conflicts. To assess the risk
wolves may pose to livestock, we initiated a 3-year study investigating
the activity patterns, movements, habitat use, visitation to livestock
pastures by wolves, and the occurrence of depredation events in an
agricultural-wildland matrix in northwestern Minnesota, USA. From June
1997 to November 1999, we captured 23 wolves, including pups, from 3
packs; we radiocollared 16 of these wolves. We tracked radioed wolves
intensively on a 24-hour basis during the spring, summer, and autumn of
1998 and 1999. We found wolves passed directly through a pasture
containing cattle on 28\% of the nights of tracking; 58\% and 95\% of
the wolf locations were <= 1 km and <= 5 km from a pasture,
respectively. Space use of wolves showed that while they visited
livestock pastures during the 24-hour tracking sessions, they
apparently were passing through these pastures with cattle and not
preying on livestock. When compared to random simulations of movements,
wolves appeared to encounter livestock pastures randomly. Thirty
percent of random movements passed directly through a pasture; 65\% and
95\% of random movements were within < 1 km and < 5 km of a pasture,
respectively. Wolves were more active at night than during the day.
Wolves avoided pastures during the day and visited pastures at night
when depredations were most likely (i.e., human presence was low).
Visitation of livestock pastures was not related to any discernible
characteristics of the pastures (i.e., pasture size, cattle density,
distance to human habitation, percent forest cover, index of deer
abundance). However, pastures in which livestock were killed by wolves
contained more cattle than pastures without depredations, but in 1998
only. While the risk of wolf predation on livestock was potentially
high (wolves were within <= 1 km of a pasture on 58\% of nights), few
livestock were actually killed. During the 3-year study, only 8 animals
(all young or vulnerable livestock) were depredated by wolves.
Maintaining healthy wild prey populations, removing offending wolves
that kill livestock, and encouraging effective and proper husbandry
practices (e.g., disposal of carcasses) among livestock producers,
should allow for the persistence of wolves in northwestern Minnesota,
USA, while minimizing their impact to farmers in this
agricudure-wildland matrix.