Translocate problem mammals away from residential areas (e.g. habituated bears) to reduce human-wildlife conflict

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • Eleven studies evaluated the effects of translocating problem mammals (such as bears) away from residential areas to reduce human-wildlife conflict. Six studies were in the USA, two were in Canada, one was Russia, one was in India and one was in Romania.



  • Survival (6 studies): A controlled study in the USA found that grizzly bears translocated away from conflict situations had lower survival rates than did non-translocated bears. A replicated study study in the USA found that fewer than half of black bears translocated from conflict situations survived after one year. Two of three studies (two controlled), in the USA, found that after translocation away from urban sites, white-tailed deer survival was lower than that of non-translocated deer. The third study found that short-term survival was lower but long-term survival was higher than that of non-translocated deer. A study in Russia found that most Amur tigers translocated after attacking dogs or people did not survive for a year after release.



  • Human-wildlife conflict (6 studies): Five studies (including one controlled and two replicated studies), in the USA and Canada, of brown/grizzly or black bears translocated away from residential areas or human-related facilities, found that at least some returned to their original capture location and/or continued to cause nuisance. In two of the studies, most returned to their capture area and one black bear returned six times following translocation. A before-and-after study in India found that leopards translocated away from human-dominated areas, attacked more humans and livestock than before-translocation. A controlled study in Romania found that translocated brown bears occurred less frequently inside high potential conflict areas than outside, the opposite to bears that had not been translocated.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A study in 1979–1981 of a large boreal and subarctic forest area in Alaska, USA (Miller & Ballard 1982) found that translocated Alaskan brown bears Ursus arctos did not settle at their release site and most returned to their capture area. Twelve of 20 translocated adult bears returned to their capture area in 13–133 days. Returning bears had been released, on average, closer to their capture site (145–255 km) than had non-returning bears (168–286 km). No translocated female bears were known to have produced young in the following year. Forty-seven bears were caught between 22 May and 22 June 1979, marked and transported by vehicle or aircraft. Adults were radio-collared and relocation data were adequate for monitoring movements and survival of 20 of these. Bears were monitored by radio-tracking from an airplane in May–October 1979 and from other radio-tracking data and hunter kills in 1979–1981.

    Study and other actions tested
  2. A controlled study in 1984–1988 at four woodland and grassland sites in Illinois, USA (Jones & Witham 1990) found that following translocation away from urban sites to reduce human-wildlife conflict, white-tailed deer Odocoileus virginianus, had a lower survival rate that did deer that were not translocated. Annual survival of translocated adult female deer (34%) was lower than that of resident adult female deer at one of the original capture sites (73%). Fifty deer (25 females, 25 males) were caught, mostly with rocket nets, between 18 December and 31 March in 1984–1988, at three largely urban sites. They were released at a rural site, ≤80 km from capture sites. Females were radio-collared and monitored every one to two weeks initially, then less frequently. Survival was compared with that of 12 additional females that were caught, radio-collared, and released at the capture site.

    Study and other actions tested
  3. A controlled study in 1975–1993 in a forested national park in Wyoming, USA (Blanchard & Knight 1995) found that grizzly bears Ursus arctos translocated away from bear-human conflict situations had lower survival rates than did non-translocated bears and over one third required multiple translocations. Translocated bears had a lower annual survival rate (83%) than that of non-translocated bears (89%). Of 81 translocated bears, 50 were moved once, 15 were moved twice, nine were moved three times, four were moved four times and three were moved five times. In a 20,000-km2 study area, 81 bears were translocated 3–128 km away from human conflict situations, such as having entered residential areas. With recaptures, there were 138 bear translocations in total between 1975 and 1993. Survival was compared with that of 160 bears captured and released without translocation during the same period. Bears were monitored by radio-tracking from an aircraft.

    Study and other actions tested
  4. A controlled study in 1995–1996 in a residential and forest area in South Carolina, USA (Cromwell et al. 1999) found that white-tailed deer Odocoileus virginianus translocated from a residential area to a nearby forest had lower short-term survival but higher long-term survival than did non-translocated deer. After three months, a lower proportion of translocated deer (52%) was alive, than of non-translocated deer (76%). After 12 months, a higher proportion of translocated deer was alive (39%) than of non-translocated deer (33%). Fifty percent of translocated deer dispersed from the release site whereas no non-translocated deer dispersed. Nineteen deer were caught with rocket nets in a residential area, in December 1995. Ten were moved 3 km and released in a forest preserve. Nine were released at the capture site. Deer were radio-collared and were monitored for up to 12 months.

    Study and other actions tested
  5. A study in 1997–2000 of a residential area and a forest in Missouri, USA (Beringer et al. 2002) found that after translocation away from a residential area, white-tailed deer Odocoileus virginianus had a lower survival rate than did deer that were not translocated. Annual survival after one year for translocated deer (30%) was lower than for non-translocated deer (69%). Among translocated deer, the largest causes of death were hunting (33%) and muscle weakness following capture (‘capture myopathy’; 29%). Among non-translocated deer, roadkill (68%) and hunting (12%) were the largest causes of death. Eighty deer (51 male, 29 female) were caught in a residential area in January–February 1999, radio-collared, and released in a conservation area 160 km away. At the same capture site, additional deer (quantity not stated) were caught, radio-collared, and released at point of capture from December 1997 to March 1998.

    Study and other actions tested
  6. A study in 2001–2004 in a mountainous protected area in eastern Russia (Goodrich & Miquelle 2005) found that following translocation of Amur tigers Panthera tigris altaica that had attacked dogs Canis lupus familiaris or people around villages, most did not survive for a year after release. One of the four translocated tigers survived for at least 10 months. The other three were killed by people, between 20 days and one year after release. Two of the animals killed were suspected to have been poached, while one was killed after killing domestic dogs. In 2001–2003, four tigers that had been involved in attacks on domestic dogs (three tigers) or a human (one tiger) were translocated 150–350 km to a protected area. Before release, two tigers, that were emaciated when caught, were held in a 1-ha enclosure for 162–388 days. All tigers were fitted with radio-collars and released into areas known to be used by wild tigers. Animals were radio-tracked approximately weekly, over an unspecified period, by researchers on foot, in vehicles, or in a plane.

    Study and other actions tested
  7. A study in 1994–1997 of extensive forest and a residential area in Ontario, Canada (Landriault et al. 2006) found that repeated translocation of an adult female black bear Ursus americanus that habitually fed from garbage containers did not prevent it from returning and resuming nuisance behaviour at the capture site. The bear was translocated six times, over distances of 40–389 km (average 152 km), and returned each time to the initial capture area. On two of the returns to the capture area, the bear was accompanied by cubs. The maximum distance between any two capture sites was 10 km. The bear habitually foraged at unsecured garbage containers in residential areas. It was caught and translocated six times between June 1994 (when estimated to be nine years old) and 1997. It was ear-tagged at first capture and radio-collared at the time of the second capture and translocation.

    Study and other actions tested
  8. A replicated study in 1982–1997 in three mainly forested areas in Ontario, Canada (Landriault et al. 2009) found that translocating black bears Ursus americanus that caused nuisance around habitation or other human-related installations reduced their nuisance behaviour, though some animals continued to cause problems. Among translocated bears, ≥30% were involved in at least one further nuisance event. This occurred mostly in adult females (48%), followed by adult males (39%), juvenile females (26%) and juvenile males (18%). Seventy-three percent of translocated adult bears returned to their area of capture, compared to 29% of juveniles. Bears released further from their capture point were less likely to return (data presented as statistical model coefficients). In each of three regions, bear relocation and tag recovery data were obtained. In total, 123 bears were relocated after displaying nuisance behaviour, and were moved on average 70–80 km. Study periods in the three areas spanned three, four and 14 years.

    Study and other actions tested
  9. A before-and-after study in 1993–2003 in a largely arable area in Maharashtra, India (Athreya et al. 2011) found that after leopards Panthera pardus fusca were translocated away from human-dominated areas, the frequency and fatality of leopard attacks on humans increased and attacks on livestock increased. There were more leopard attacks on humans after translocations began (8–24/year) than before (1–7/year) and these resulted in more human fatalities (after: 3–11/year; before: 0–2/year). There were more leopard attacks on livestock after translocations began (average 166 attacks/year) than in the 12 month before translocations began (106 attacks). Authors reported that the attacks were by the translocated leopards. In a 4,275-km2 study area, with a human population density of 185 people/km2, 103 leopard translocations occurred between February 2001 and December 2003. Eighty-six leopards were caught in human-dominated areas, with 29 translocated <60 km to either of two natural forest sites and 56 moved >200 km to release sites elsewhere. Eleven leopards from outside the study area were also released at the natural forest sites. Location data were not available for six translocations. Human attack data during the translocation period were compared with those collated for 1993–2000.

    Study and other actions tested
  10. A controlled study in 2008-2011 in a mixed landscape in the Eastern Romanian Carpathians, Romania (Pop et al. 2012) found that brown bears Ursus arctos translocated to reduce conflict with humans, some of which had been rehabilitated as orphans, occurred less frequently inside high potential conflict areas than outside. Bears were present less frequently inside high potential conflict areas than outside if they had been translocated (occurrences inside: 501; outside: 1,517) or rehabilitated (inside: 462; outside: 1,180) and particularly if they had been rehabilitated and translocated (inside: 245; outside: 963). Bears that had not been translocated or rehabilitated occurred inside the high potential conflict areas more than outside (inside: 2,166; outside: 1,067). Rehabilitated and translocated bears spent less time (9 hrs) in the conflict areas than those that had not been rehabilitated and translocated (14 hrs). Similar time was spent in those areas by bears that had just been translocated (4 hrs) or rehabilitated (6 hrs). Eight bears were radio-tracked for 3-17 months (541-1,869 locations/bear) in 2008-2011 across the 15,822 km2 study site. There were two bears of each of four types: translocated but not rehabilitated, translocated and rehabilitated, not translocated but rehabilitated and not translocated or rehabilitated. The four bears (two male) were translocated >60-100 km from their capture site due to conflict with humans (damage and/or frequently visited settlements, e.g. waste disposal sites). Four bears (two male) were orphan bear cubs that were released after rehabilitation in relatively natural conditions for a maximum of two years. High potential conflict areas were those with human settlements, partially agricultural fields and woodlands.

    Study and other actions tested
  11. A replicated study in 1995–1997 in an unspecified number of mountain sites in Colorado, USA (Alldredge  et al. 2015) found that after translocation of black bears Ursus americanus that were involved in conflict with humans, fewer than half survived after one year and some returned to capture sites. One year after translocation, 50% of adult black bears and 28% of sub-adult bears had survived. Of 66 captured bears, 14 returned to capture sites and 16 repeated some form of problem behaviour. In May and October of 1995–1997, sixty-six bears that were considered a nuisance or threat to human safety were captured. All were individually marked with ear tags and lip tattoos and were fitted with radio-collars. Within two days of capture, bears were translocated to release sites. Not statedBears were radio-tracked opportunistically, from the ground and from a plane, once a week, in May–October of 1995–1997.

    Study and other actions tested
Please cite as:

Littlewood, N.A., Rocha, R., Smith, R.K., Martin, P.A., Lockhart, S.L., Schoonover, R.F., Wilman, E., Bladon, A.J., Sainsbury, K.A., Pimm S. and Sutherland, W.J. (2020) Terrestrial Mammal Conservation: Global Evidence for the Effects of Interventions for terrestrial mammals excluding bats and primates. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.

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Terrestrial Mammal Conservation

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Terrestrial Mammal Conservation

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