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Minimizing conflicts with humans is a necessary component of the management of American black bears (Ursus americanus) across most of their range. The number of complaints about conflicts with black bears is commonly used to infer trends in the actual frequency or severity of human–bear conflict, and even trends in bear population size. However, the number of complaints received by management agencies is a function of both the frequency of and the reporting rate for conflicts, and the reporting rate may change over time. We tested for effects of food availability, numbers of bears harvested, and management regime changes on 3 measures of human–bear conflict: (1) public complaints, (2) traps set to capture bears involved in conflicts, and (3) bears killed in defense of property in Parry Sound, Ontario, Canada, 1992–2008. All measures of human–bear conflict were inversely related to food availability. Complaints increased following a controversial change in management (cancellation of the spring hunting season), but numbers of traps set and bears killed were not affected. We suggest that an increase in the reporting rate was largely responsible for the increase in complaints following the spring hunt cancellation because (1) an effect on the actual frequency or severity of human–bear conflict should also have been detected in data for traps set but was not, and (2) neither the number nor the sex ratio of harvested bears changed when the spring hunt was cancelled, so the effect of harvest on population size and sex ratio was not altered by the management regime change. Trends in the actual frequency and severity of human–bear conflict should not be inferred from trends in complaint data unless factors that could affect the reporting rate for conflicts are accounted for.
Asiatic black bears (Ursus thibetanus) and sun bears (Helarctos malayanus) in Southeast Asia leave claw marks on climbed trees that provide a cumulative history of their presence and activities, but this record can be difficult to interpret without knowing the age of the marks. We conducted an experiment to estimate ages of bear claw marks by monitoring 212 fresh claw mark sets (most of which we created to mimic real claw marks) on 122 trees from 17 families in Thailand. We categorized marks as looking fresh (presence of woody grit, sharp edges), recent (absence of woody grit), or old (bark growth in the gouges), and estimated the duration of these age categories using Kaplan-Meier survival analysis. Most marks (81%) remained fresh for at least 2 months, but by 3 months, 75% had transitioned to recent (median 2.6 months). By 10 months, 90% of fresh marks became old (median 7.3 months). Wood hardness had no effect on aging rates. Marks created in the rainy season and those on thin-barked trees aged slightly faster than dry season marks or marks on thick-barked trees, but these differences were slight enough that they could be disregarded in population monitoring programs based on abundance of sign. Simulation models we constructed indicated that the density of fresh (or fresh plus recent) sign would more closely correspond with the number of bears in an area than would the density of all sign or the ratio of new∶old sign, because old sign persists for a long (≥24 months) and variable time, so would tend to be a poor reflection of bear abundance. Fresh claw marks also can be linked to phenology and fruit production of climbed trees, so could provide information on bear feeding habits.
We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their human–bear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in human–bear management and use them in a consistent manner. We constructed a human–bear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among human–bear management agencies. Specifically, we defined 40 terms and concepts in human–bear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide human–bear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America.
Grizzly bears (Ursus arctos) occur across British Columbia and in Alberta in mostly forested, mountainous, and boreal ecosystems. These dense forests make sighting bears from aircraft uncommon and aerial census impractical. Since 1995, we have used genetic sampling using DNA from bear hair collected with barbed wire hair traps to explore a suite of ecological questions of grizzly bears in western Canada. During 1995–2005, we conducted large-scale sampling (1,650 to 9,866 km2 grids) in 26 areas (covering a combined 110,405 km2), where genetic identification of 1,412 grizzly bears was recorded. Abundance estimation was the primary goal of most surveys. We also used DNA from bear hair to examine population trend, distribution, and presence in areas where grizzly bears were rare, as well as population fragmentation in a region with a high human population. Combining spatial variation in detecting bears with that of human, landscape, and ecological features has allowed us to quantify factors that influence grizzly bear distribution, population fragmentation, and competition with black bears (U. americanus), and to map variation in bear densities. We summarize these studies and discuss lessons learned that are relevant to improving sampling efficiency, study designs, and resulting inference.
We recorded the nursing vocalization of a wild polar bear (Ursus maritimus) cub in Svalbard, Norway and describe it with the term humming. From a 3-minute recording of the vocalization, we found the sounds composed of between 30–55 pulses with a mean of 0.05 (SE = 0.002) seconds in duration, a frequency with the greatest energy at 0.28 kHz (SE = 0.06), and a mean maximum frequency of 0.85 kHz (SE = 0.15). The function of the pulsed vocalization is unknown but may relate to comfort and contentment or to stimulate milk release by the mother.
We describe an incident we investigated in which a photographer on the Shiretoko Peninsula, Hokkaido, Japan observed a pair of adult brown bears (Ursus arctos yesoensis) mating on 11 October 2009. After an interview and examination of photographs, we conclude that the mating did occur on the reported date. Copulation evidently lasted about 30 minutes without overt struggle either before or after the event. Several days prior to the date, a female, which we presume to be the one involved, was seen with swollen and colored genitalia, suggesting she was in estrus. Only a single mating was witnessed and neither of the bears was observed after this date. Throughout its range, mating of brown bear is rarely observed in autumn, and this is probably the first record in Hokkaido.