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Steven H. Fritts

Publications and source records attributed to Steven H. Fritts.

7 recordsLinked to original sources
USGS2017

An unparalleled opportunity for an important ecological study

Wolves ( Canis lupus ) and moose ( Alces americanus ) have been studied since 1958 on 540-square-kilometer Isle Royale National Park, in Lake Superior. Wolves arrived there across the ice around 1949, and the population once increased to about 50, averaging about 25 annually (Mech 1966 , Jordan et al. 1967 , Vucetich and Peterson 2009 ). However, for various reasons, wolf numbers there have now dwindled to 2 nonbreeders, and the US National Park Service has proposed reintroducing 20–30 wolves over 3 years (National Park Service 2016 ). This situation offers an unparalleled opportunity to promote science-based management of this unique national park. The park has long been in the public eye for its world-renowned wolf and moose populations. Visitors to this island wilderness are especially interested in the scientific studies it has yielded and in maintaining its ecosystem.

Michigan↗
USGS1986

Trap-related injuries to gray wolves in Minnesota

Gray wolves ( Canis lupus ) captured in traps with toothed jaws offset 1.8 cm incurred fewer injuries than those captured in 3 other types of steel traps. Few wolves seriously damaged canine or carnassial teeth while in traps.

Minnesota↗
USGS1985

Can relocated wolves survive?

Considerable interest has been expressed recently in establishing gray wolves ( Canis lupus ) into parts of their former range (Bailey 1978, Weaver 1978, Klinghammer 1979, Mech 1979, Henshaw 1982). However, the proper procedure for reintroductions is debatable (Klinghammer 1979). To date, wolf relocations have been conducted in Alaska, where 5 2-year-old captive-reared wolves were released into an area occupied by wolves, (Henshaw and Stephenson 1974, Henshaw et al. 1979) and in Michigan, where a pack 4 wolves was released in a relatively wolf-free area (Weise et al. 1975). Wolf reintroductions are expensive, controversial, and attract considerable public attention. The potential for success of an effort will greatly influence the willingness of agencies to attempt reintroductions. The 9 wolves released in Alaska and Michigan had a high rate of mortality, with humans being the major cause. The present study assessed the survival and behavior of relocated wolves. We hypothesized that relocated wolves, especially pups, would have poorer survival when moved outside a familiar territory.

Minnesota↗
USGS1984

Movements of translocated wolves in Minnesota

From Feb. 1975-May 1978, 104 wolves ( Canis lupus ) captured at or near Minnesota farms where depredations on livestock had been reported were translocated northward and eastward for 50-317 km into extensive forests; 3 others were released westward. Nine wolves were translocated twice, and 1 three times. Information on movements was obtained by radiotracking 17 wolves and by recovery of 16 others. All radio-tagged wolves left the release areas; adults left quickly, but pups generally remained longer, behaved less decisively, and settled nearby temporarily. Wolves released together did not remain together. Initial travel of most radio-tagged adults was between south and west, the general direction to their original location. Final directions were primarily to the west and northwest, due in part to physiographic barriers. Eight adults homed, 1 twice, to capture areas that were < 64 km from release sites. Nonhoming wolves were radiotracked and/or recovered 32-351 km from their capture sites and 23-302 km from their release sites. Translocation was largely unsuccessful at keeping problem wolves out of lifestock production areas. The problem of initial travel away from release sites in wolf reintroductions probably could be minimized by transport and release of 6-9 mo. old wolves.

Minnesota↗
USGS1983

Pack size and wolf pup survival: their relationship under varying ecological conditions

The relationship between pack size and two parameters of reproductive success (litter size at 7–8 months and pup weights at 5–6 months) were determined for two wolf ( Canis lupus ) populations in northern Minnesota. Pup weights were not correlated with pack size for either population. Litter size, however, was correlated with pack size, but the direction of the relationship varied between the two study populations. In the superior National Forest, where prey were scarce and the wolf population was declining from high densities, litter size and pack size were inversely related. Pairs produced more surviving pups than did larger packs with one or more potential helpers. In the Beltrami Island State Forest, where prey were relatively abundant and the wolf population was increasing, pack size and litter size were positively correlated. The results suggest that ecological factors, such as prey availability, affected the ability or willingness of various pack members to provide food or other care for the pups. The lack of correlation between number of auxiliaries and number of pups in canid populations with low and declining prey densities may be explained on the basis of heterogeneous prey density resulting in drastic annual variation in litter production. No study to date has measured the actual benefit that pups derive from helping by auxiliaries, and the costs and benefits of it. The relationships discussed herein can be considered valid only after such research is completed.

Behavioral Ecology and Sociobiology↗
USGS1983

Chewing-removal of radio collars by wolves in Wisconsin

From May 1980 through august 1981 we placed 11 machine-belt radio collars on 10 adult gray wolves ( Canis lupus ) from 4 packs in northwestern Wisconsin. This note reports the loss of 7 collars from chewing by other wolves, apparently pack-mates.

Wisconsin↗