Activity patterns of urban American black bears in the San Gabriel Mountains of southern

Amy J. Lyons1

CaliforniaDepartment of Fish and Game, 2440 MainStreet, Red Bluff,CA 96080, USA

Abstract: Both the Americanblack bear (Ursus americanus)population in the San GabrielMountains of , California,USA, and the human populationat the base of these mountains have grown, and human-bearinteractions are common. Little is known aboutthe habits of urbanbears in .From July 1998 to December 1999, I studied the activity patternsof urban black bears in the foothills of the San GabrielMountains and describedtheir use of adjacentcities. I trappedand radiocollared2 female and 4 male bears and monitoredtheir movements in forest and city habitatsusing ground-basedand aerial radiotracking.The female bears used city all seasons (spring, summer,fall, winter)of this study, with the exception of the second fall season by one female. Male bears used city habitat during summer, with little exception. Female bears used city habitat equally during4 6-hr periods daily in summer 1998 and used the city heaviest from 1600-0359 hr in spring 1999 and from 2200-0959 hr in summer 1999. Male bears used city habitatmost during the 2200-0359 hr period. Bears were most active in cities during late night when human activity was minimal. Public education efforts to inform residents about activities and behaviors to reduce bear attractantsappeared to be successful, are supportedby the Department'scurrent black bearpolicy, and indicate that a focus on human educationand enforcementof attractantcontainment and removal are necessary for minimizing bear-humanconflict.

Key words: , black bear policy, nuisance bears, San Gabriel Mountains, southernCalifornia, urbanbears, Ursus americanus

Ursus16(2):255-262 (2005)

The American black bear (Ursus americanus) was USA, personal communication, 1998). The human introducedinto the San Gabriel Mountainsof southern population at the base of the San Gabriel Mountains Californiain 1933, when the CaliforniaDepartment of has also increased, resulting in urban and suburban Fish and Game (Department)relocated 11 bears from sprawl.These populationincreases have createda situa- Yosemite NationalPark to an areanear CrystalLake. At tion where human-bear interactionsare now common the same time, 16 bears were released in the adjacent (D. Updike, CaliforniaDepartment of Fish and Game, San BernardinoMountains (Burghduff 1935). The San Sacramento,California, USA, personal communication, Gabriel bear population has since experienced little 1998), as bears include residential areas within their hunting pressure because the rough, steep terrain home ranges (Van Stralen 1998). Many residenceshave most hunters. discourages Bear hunters have reported yards containing ornamental avocado and fig trees, taking an average 7 bears per year (Departmentbear while others contain small remnant avocado orchards. harvest data for 1986-2001 hunting seasons, Los Bears frequentlyvisit and obtainfood from garbagecans Angeles County, California,USA). and dumpsters, fruit trees, barbecues, and pet food In the absence of natural predators and hunting bowls, and enter swimming pools. the San Gabriel pressure, bear populationhas grown to Although the Department receives many nuisance 250-300 approximately bears (R. Stafford, California complaints,few are relatedto serious damage or threats of Department Fish and Game, Sacramento,California, to humans (Davis and Brennan 1996). Residents of the interface communities do not wish harm to bears, but they do expect a response to increasing conflicts (C. Davis, California Departmentof Fish and Game, [email protected] Ontario, California, USA, personal communication,

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1998). Although city councils have insisted on the sagebrush scrub (Artemisia tridentata), scrub relocation of the nuisance bears, the Department's (Quercus dumosa), desert chaparral(Ceano- currentblack bear policy prohibitssuch action. thus greggii-Cercocarpus ledifolius), pinyon-juniper Several black bear studies were conductedin the San woodland (Pinus monophylla-Juniperus californica), GabrielMountains (Moss 1972, Braden 1991, Stubble- and Joshuatree woodland (Yucca brevifolia).The high- field 1992, Stubblefield and Braden 1994) and the elevation plant communities are yellow pine forest adjacent San Berardino Mountains (Boyer 1976, (--Pinus coulteri), sub- Siperek 1979, Novick et al. 1981, Novick and Stewart alpine forest (Pinus murrayana-Pinus flexilis), and 1982, Hogan 1984), but none evaluated the habits of alpine fell-field dominatedby Eriogonumsaxatile. The urban bears. The Departmentdesigned a 3-year study riparianwoodland plant communityis found in different to address this issue (Davis and Brennan 1996). A forms at low (Platanus racemosa-Populus fremontii), preliminary feasibility study was conducted the first mid (Alnusrhombifolia), and high (Pseudotsugamacro- year of research from July 1997 to June 1998 (Van carpa) elevations (Hanes 1976). Stralen 1998). The second and third year of research My study areaincluded the San GabrielRiver Ranger (July 1998 to December 1999), I studied activity District, as well as portions of the following cities: patters of urban black bears in the foothills of the Arcadia,Monrovia, Bradbury, Duarte, Azusa, Glendora, San Gabriel Mountains and described their use of San Dimas, La Verne, and Claremont. The human adjacentcities. populations of these foothill cities range from 860 to 53,100 people, with an average population of 34,200 people. Population growth from 1990 to 2000 ranged Study area from 3.0%to 10.4 %,with an averagepopulation increase The San Gabriel Mountains are located in Los of 5.6%. Populationdensities range from 174 to 1,940 km2 Angeles County, California, USA, and are largely people per km2,with an averageof 1,178 people per included in the . The mountains (City-data2003, ePodunk2003). run east to west for approximately113 km, encompass- ing an area of approximately 19,370 km2. The mountains are bounded on the north by the Mojave Methods Desert, on the west by the San Ferando , on the Capture and marking volunteers to south by the Los Angeles Plain, and on the east by the Department personnel and attempted San Berardino Mountains(Miller 1928). trapbears from Januaryto mid-Augustin 1998 and 1999 bear Elevation ranges from approximately 152 m at the in urbanareas that demonstratedconsistent activity. base of the foothills to over 2,743 m at a few peaks. Trapping was suspended during bear hunting season in accordance with Food and Ridges generally have slopes of 20 to 40 degrees. The (mid-Aug through Dec) steep slopes combined with the presence of fractured Drug Administrationregulations. were set in basementrock contributeto frequentlandslides (Morton Culverttraps (Piekielek and Burton 1975) in small orchardsof homes that 1973). Debris basins have been built at the base of the driveways, on lawns, or bear Baits included canyons for flood and debris control. experienced repeated problems. Climate varies with elevation. The average annual a variety of aromatic items such as cat food, canned or donated butcher The precipitationis 90.3 cm, and averageannual temperature tuna, sardines, bacon, scraps. dawn. is 13.4?C.Winters are mild and wet with rainfall,while traps were set and baited at dusk and closed at were instructed to me or higher elevations receive occasional snowfall. Summers Residents page Department when heard the door close. are typically dry and hot with occasional thunderstorms dispatch they heavy trap immobilized and windstorms ( Regional Climate Center Once trapped, bears were chemically et al. 1980, 2000). Climate on the south-facingside of the range is with tiletamine hydrochloride (Stewart and 1995) a Dan-inject subjectto coastal influences, while the north-facingside Burton Schmalenberger using stick Pharmaceuticals Fort is subject to desert influences (Hanes 1976). jab (Wildlife Incorporated, Each bear was fitted with Lower elevation plant communities of the mountain Collins, Colorado, USA). Mesa, Arizona, USA) equipped range are coastal sage scrub (Artemisia californica), a radiocollar(Telonics, switch hr The collars were chamise chaparral (Adenostoma fasciculatum), and with a mortality (5.5 delay). white reflective southern oak woodland (Quercus agrifolia-Juglans markedwith orange,red, yellow, or tape visual identificationof bears. californica). The mid-elevation plant communities are to allow easy Ursus 16(2):255-262 (2005) ACTIVITYPATTERNS OF URBAN BEARS * Lyons 257

Standardmorphometric measurements, condition of by the total number of telemetry locations. The same teeth (worn, broken, stained) and externalparasite load calculation was performedfor the number of telemetry were recorded.Each bear received a colored plastic tag, locations gathered within city boundaries.I used these a metal numberedtag, or both in each ear. I assigned calculations to report percent use of city and forest every capturedbear an identificationnumber beginning on a monthly and seasonal basis. I defined with an "F" for female or an "M" for male, followed by seasonal ranges (Novick and Stewart 1982) as: spring their unique 3-digit collar frequency. (1 Apr-30 Jun), summer (1 Jul-30 Sep), fall (1 Oct- When necessary, bears were released in the nearest 31 Dec), and winter (1 Jan-Mar 31). undeveloped area to avoid immediate bear-human I compared the distribution of telemetry locations conflicts. Displacementdid not exceed 400 m. gathered within city habitat over the 4 daily periods describedabove to determineif bearactivity was equally Monitoring distributedamong periods.I summarizednumber of bear Beginning 15 July 1998 and continuing until 31 locations within cities by period to compare activity December 1999, I monitored movements of collared inside city limits within and among seasons using a bears using discontinuous radiotracking(Harris et al. chi-square goodness-of-fit analysis (Zar 1984). When 1990). I located bears using standard methods of observed use differed from expected, I divided the ground-basedtriangulation with a receiver attached to chi-squareanalysis to determinewhich period was used an Omni car-top antenna and a Yagi "H" hand-held disproportionately. antenna. I attemptedto obtain at least 3 bearings per I was unable to analyze daily activity among periods location within 30 min, but accepted locations based for individual bears because >20% of the expected upon 2 bearingswhen bears were close (<250 m) to the frequencies were <5 for most individuals (Zar 1984). receiver or when topographyand road access precluded Instead, I pooled data from the 2 females for one additionalbearings. When possible, errorpolygons were analysis and pooled data from 3 of the 4 males for the constructedand locations associatedwith large polygons other analysis (the fourthmale was not includedbecause were censured. he stopped frequentingthe city 2 weeks after capture). Data points were gathereddaily per bear on as many bears as possible during active periods, but only once or twice per week per inactive bear during denning. I Results continued to search for each bear until I located it, Capture and marking that I had the same to a ensuring potential register Despite nearly continuous trapping effort during location in the forest as in habitat. city January-August,bears were only capturedduring July I also located bears once or twice month per through and August in 1998. Two bears captured during the aerial and Garrott with the radiotracking(White 1990) preliminarystudy (1997) had been fitted with drop-off assistance of a aircraft.Addi- Departmentfixed-wing collars. Both were recapturedduring the second year of tional data were from points gathered reportedpositive study and fittedwith new collars. One bear was captured identification of bears homeowners or provided by free-rangingin a neighborhood,3 bears were trapped, police departments. and 2 were dartedand removed from trees in residential I located bears for them with by searching equal areas during daylight hours. Bears were captured in each of 4 6-hr that intensity during periods represented Monrovia, Bradbury,Glendora, and Claremont.In all, morning (0400-0959 hr), mid-day (1000-1559 hr), 2 adult female and 4 adult male bears were collared. evening (1600-2159 hr), and late night (2200-0359 hr). Each location was accompaniedby descriptivedata Monitoring including latitude, longitude, elevation, time of day of I gathered 2-3 bearings consecutively on each bear the location, and location relative to city or forest. (x = 2.3 bearings/usablelocation). Over 92% of the bearings were gathered within 15 minutes of the pre- Activity patterns vious bearing. Elapsed intervals between consecutive I defined "forest" as areas within the Angeles fixes were 2-27 minutes (x = 7.2 min). National Forest and vegetated, undeveloped areas During winter months, 3 male bears (M025, M265, surroundingcities. I defined "city" as developed areas and M290) retreatedinto the forest above the snow line within limits. For each city bear,I divided the numberof and became inactive; the fourth male (M545) retreated locations within the telemetry gathered forest boundary to a chaparralarea just above and behind the city, where Ursus 16(2):255-262 (2005) 258 ACTiVITYPATTERNS OFURBAN BEARS * Lyons

Table 1. Use (% of time) of forest and city habitat by Table 2. Use (% of time) of forest and city habitat 2 female black bears in the San Gabriel Mountains, by 4 male bears in the San Gabriel Mountains, Los Los Angeles County, California, USA, on a monthly Angeles County, California, USA, on a monthly and and seasonal basis, July 1998-December 1999. seasonal basis, July 1998 to December 1999. BearF225 BearF375 BearM025 BearM265 BearM290 BearM545 Time Forest City Forest City Time Forest City Forest City Forest City Forest City 1998 1998 Jul 50 50 n/a n/a Jul n/a n/a 40 60 17 83 100 0 Aug 43 57 36 64 Aug 71 29 70 30 8 92 64 36 Sep 70 30 72 28 Sep 100 0 100 0 61 39 70 30 Summer 56 44 59 41 Summer 75 25 76 24 42 58 72 28 Oct 65 35 94 6 Fall 100 0 100 0 86 14 90 10 Nov 83 17 100 0 1999 Dec 93 7 100 0 Winter 100 0 100 0 100 0 100 0 Fall 79 21 87 13 Spring 100 0 78 22 100 0 n/a n/a 1999 Jul 100 0 63 37 67 33 91 9 Jan 90 10 100 0 Aug 100 0 71 29 60 40 56 44 Feb 93 7 100 0 Sep 100 0 94 6 n/a n/a 40 60 Mar 75 25 90 10 Summer 100 0 76 24 62 38 60 40 Winter 88 12 98 2 Fall 100 0 100 0 n/a n/a 100 0 Apr 68 32 69 31 May 37 63 58 42 Jun 39 61 61 39 67 33 Spring 48 52 in Septemberof 1998 (data are incomplete for this bear Jul 57 43 67 33 because it was killed a hunterat the end of summer 50 50 82 18 by Aug Bear M545 used habitat in and Sep 31 69 55 45 1999). city August Summer 48 52 67 33 Septemberof both years, and used the city minimallyin Oct 100 0 69 31 October of 1998 and July of 1999 (data are incomplete Nov 100 0 86 14 for this bear because he dropped his collar at the end Dec 100 0 100 0 of winter 1999 and was not until summer Fall 100 0 78 22 recaptured 1999; Table 2). Daily activity within the city. The 2 female bears I trackedmale he also became inactive. Consequently, consistently used city habitat during summer 1998, winter.Both females remained bearsonly weekly during spring 1999, and summer 1999. Female daily activity winter I therefore con- active throughoutthe months; patterns differed between summer 1998 and summer tinued to track them daily. 1999 (P < 0.025), and between summers and spring Of 1,064 data points gathered, 77% were obtained 1999 (P < 0.025). 3% using groundtelemetry, 17% using aerialtelemetry, Female activity in the city was equally distributed from reportedsightings by residentsor law enforcement across the 4 daily periods during summer 1998 (P > from officers, 2% from researcher sightings, and 1% 0.75), but not during spring and summer 1999 (P < captureand recapturelocations. 0.005). In spring 1999, females were more active than expected during the 1600-2159 hr and 2200-0359 hr summer female bears Activity patterns periods. In contrast,during 1999, 2200-0359 hr Forest versus city use. Bear F225 used city were more active than expected during habitat for 15 consecutive months from July 1998 and 0400-0959 (Fig. 1). bears used the through September 1999. Bear F375 used city habitat The 3 male consistently city only summer1998 and summer1999, and their4 August through October 1998 and March through during daily November 1999 (Table 1). activity patternswere consistentbetween summers(P > males moved Bear M025 used city habitatonly in August of 1998. 0.95). However, during summer, actively hr than Bear M265 used city habitatduring July and August in within the city more during 2200-0359 during as reflected in a to both years. In Septemberof 1999, he used the city only the other 3 periods (Fig. 2), change < when this was minimally. Bear M290 used city habitatduring July and significant x2 values (P 0.01) period in the August in both years, and used the city to a lesser extent included analysis. Ursus 16(2):255-262 (2005) ACTIVITYPATTERNS OF URBANBEARS * Lyons 259

Discussion 25 ---=0 )-1559 h Capture and marking 16000-2159 h 02200-0359 h I difficulties 20 experienced unexpected 0-0959 h while trapping. Many residents in the foothill areas enjoyed watching and photo- graphing bears and became angry when 15 they discoveredthat I was going to trapand

collar the bears. Despite efforts to inform 10 them about the study, I experiencedseveral Z incidents of trap sabotage. Consequently,I was forced to monitor the trap when it was set, dramaticallyreducing trapping effort. Trapping efficiency was also lowered by 0 several instances of bears from Summer98 Spring 99 Summer 99 escaping Season traps,the captureof a domestic dog, and the abundanceof foods, namely avocados and Fig. . Number of telemetry locations in habitat for 2 female available to bears in the cities. city garbage, bears witlhin each of 4 daily periods during an urban black bear Perhaps trapping success would have im- study in the San Gabriel Mountains, Los Angeles County, proved if attractantsin the surroundingarea California, USA. were removed or secured before the trap was baited and set. summers and traveled far into the mountains during Activity patterns early fall 1998 to a fruit orchard,where he remainedfor Forest versus city use. Both females had cubs in a short time before returing to an area just above the 1998 and remainedactive year-round,but they traveled city. It is also possible that the females used the city for alone duringthe second fall and were relativelyinactive a longer period due to the higher energetic demands of as they preparedfor hibernation.Bear F225 used city lactationor gestation. habitatto some extent in every month of the firstyear of Daily activity within the city. In summer 1998, study, but retreatedto the forest in October 1999. During both female bears had young cubs with them and summer1999, F225 spent most nights feeding in a small they were equally active throughout the day, which avocado grove, whereas F375 visited various areas may result from the energetic demands of the young within the city limits. I believe the constant supply of a fattening food allowed F225 to achieve a threshold condition for denning and reproduc- 18 tion earlier than F375, which may 16- explain F225's lack of use of city 14 habitatin fall 1999. 2 12 1.000-1559 h The 3 male bears using city habitat I 1600-2159 h ------did so consistently throughout both o 10------2200-0359 h *0400-0959 h summers,but they did not use the city E s- z in fall, winter, or spring, with the exception of minimal use precedingor following summer. Their lower in- cidence of location within the city 2-- than females may be related to the home of which Summer 98 Summer 99 larger ranges males, Season potentially expose them to more and varied sources of foods. For example, Fi. 2 Number of telemetry locations in city habitat for 3 male bears bear M545 visited a 40-acre avocado within each of 4 daily periods during an urban black bear study in the orchardoutside of the city duringboth San Gabriel Mountains, Los Angeles County, California, USA.

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(Ayres et al. 1986). The two females' use of city habitat bearsmay also be more tolerantof humandisturbance in shifted from 1600-2159 hr and 2200-0359 hr periods in orderto obtainthe abundantfood resourceswithin the city. spring 1999 to 2200-0359 hr and 0400-0959 hr periods in summer 1999. This shift in activity may have been in Removal of attractants response to a change in human activity, as human The Department's current black bear policy is activity typically continues later into the evening during intended, in part, to minimize bear-human conflicts. summer months due to a later sunset and warmer The policy recognizes improperstorage of garbage as temperatures. a majorcause of interactionsbetween bears and humans The 3 males displayed identical daily activity pat- and stressesthe need to reduce or eliminateattractants in terns during both summers.In summer,they were most the city. For the durationof the study, I distributedthe active in the city late evening to early morning (2200- Department's "Living with California Black Bears" 0359 hr). This pattern of activity within the city was brochureto residentsin neighborhoodsthat had regular also displayedby the 2 female bears in spring and sum- visits from bears or were adjacentto areas of high bear mer 1999. activity. Several community meetings were jointly These patternsof activity are most likely relatedto the organized by Departmentpersonnel and local police to urban setting. Wild black bears are mostly diurnal educate the public about removal of attractants.Several (Amstrup and Beecham 1976, Lindzey and Meslow residentsfollowed our advice to secure garbagecans and 1977, Garshelis and Pelton 1980, Ayres et al. 1986, place them out on the streetonly on the morningof pick- Lariviereet al. 1994). However, black bears have been up (ratherthan the night before), bring pet food inside, known to shift to nocturnal activity in areas where clean barbecuegrills, and remove ripened and dropped humanactivities are prevalentduring the day (Reimchen fruit from trees and on the ground;they reportedto me 1998). Activity budgets when bears were within city that bear activity declined or ceased in their area. habitat reflect the period of minimal human activity, However, this strategy only seemed to work when all a response observed in other studies of bears that used residents of an area complied. Some residents admitted human food sources (Ayres et al. 1986, Mattson 1990). that they left out attractantsbecause they enjoyed seeing the bears; this caused neighbors to continue having bear problems. Managementimplications Residents with avocado groves or similar fruit Majorattractants within cities (garbage,pet food, and producing trees (attractantswhich are not removable) avocados) are available year-round.Yet the 6 bears in were given guidelines for constructing bear-proof this study used these areas only during summer. electric fencing. To my knowledge, this suggestion The cities of Similarly,Boyer (1976) found that despite a year-round was not implemented by any residents. considered garbage supply at a study site in the San Bemardino Monrovia and Bradbury upgrading public Mountains, bears ate less garbage as natural foods garbage cans to bear-proofmodels. However, the local became more available from spring to fall. waste managementcompany concluded that the cost of In studies of seasonal elevation use in the San altering their garbage trucks to enable the pick-up of Berardino Mountains, Novick (1979) and Hogan bear-proof cans was prohibitive (C. Davis, California (1984) found that centers of activity for black bears Department of Fish and Game, Ontario, Califoria, occurred at low elevations in spring and summer. The USA, personal communication,2000). bears then traveled to higher elevations in the fall, and even higher elevations in the winter. Novick (1979) Future management strategy current black bear is speculated that this movement to higher elevations in The Department's policy bear in the fall reflects the phenological progression of berry pro- appropriatefor the urban black population of the San Gabriel Mountains. More ducing plants and acons. foothill cities It is conceivable that the bears of the present study intense efforts towardpublic educationand enforcement of travel to lowest elevations within home ranges during of the removal of attractantsshould be the focus for all bear springand summerand consequentlyend up on the edge a future management plan populations in California. of cities. Once there,they are drawninside city limits by inhabiting the urban-wildland interface codes that enable numerous attractantsduring a time when naturalfood Individual cities can enforce county of sources are scarce and caloric intake requirementsare law enforcementto cite residents who live in areas if do not contain and high. During this time of scarcity of naturalfoods, the high bear activity they properly Ursus 16(2):255-262 (2005) ACTIVITYPATTERNS OF URBAN BEARS * Lyons 261 secure garbage, do not bring in pet food bowls, or EPODUNK.2003. Census and demographics for Arcadia, purposely feed bears. This shift from correcting the Monrovia,Bradbury, Duarte, Azusa, Glendora,San Dimas, behavior of the bears to correcting human behavior has La Verne, and Claremont. ePodunk, Ithaca, , USA. accessed been adopted by other cities experiencing urban bear http://www.epodunk.com, October2003. GARSHELIS,D., AND M. PELTON. 1980. of black bears problems (Peine 2001), and in most cases has led to the Activity in the . Journal requirement of bear-proof garbage containers for of Mammalogy61:8-19. residents. Future studies should address the effectiveness HANES,T. 1976. Vegetationtypes of the San GabrielMountains. and of this possible implementation strategy. Pages 65-76 in J. Latting, editor. Plant communities of Southern California. Symposium Proceedings. California Native Plant Society, Berkeley, California,USA. Acknowledgments HARRIS, S., W. CRESSWELL, P. FORDE, W. TREWHELLA, T. WOOLLARD,AND S. WRAY. 1990. Home-range analysis Funding was provided by the Los Angeles County using radio-trackingdata- a review of problems and Fish and Game Commission and the California De- techniquesparticularly as appliedto the study of mammals. partment of Fish and Game's Black Bear Program. My MammalReview 20:97-123. sincerest thanks to C. D. R. Davis, Updike, Stafford, M. HOGAN,D. 1984. Home range and habitat preferences of Jeter, T. Evans, G.R. Stewart, G.R. Trapp,the Depart- female black bears in the San Berardino Mountains of ment's game wardens, local police officers, K. Bosell, southern California. Thesis, California State Polytechnic K. Argent, and numerous volunteers who assisted this University, Pomona, California,USA. study. I thank G.R. Stewart, F. Wemette, and D. Updike LARIVIERE,S., J. HUOT,AND C. SAMSON.1994. Daily activity for editing an early draft, as well as R. Harris,C. Mc- patternsof female black bears in a northernmixed-forest Laughlin, J.D. Peine, and an anonymous reviewer for environment.Journal of Mammalogy75:613-620. comments and suggestions. LINDZEY, F., AND C. MESLOW. 1977. Home range and habitat use by black bears in southwesternWashington. Journal of Wildlife Management41:413-425. MATTSON,D. 1990. Human impacts on bear habitat use. Literaturecited InternationalConference on Bear Research and Manage- AMSTRUP,S., ANDJ. BEECHAM.1976. 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Detailed profile for Arcadia, Monrovia, preferencesof black bearsin the San BernardinoMountains Duarte,Azusa, Glendora,San Dimas, and Claremont.City- of southernCalifornia. California Fish and Game 68:21-35. data.com. accessed http://www.city-data.com, October2003. PEINE,J. 2001. Nuisance bears in communities:Strategies to ANDK. DAVIS, C., BRENNAN.1996. Investigationof black bear reduce conflict. HumanDimensions of Wildlife 6:223-237. habitatusage and behaviors the urbanfoothill inter- along PIEKIELEK,W., ANDT. BURTON.1975. A black bear population face. California Departmentof Fish and GameDraft Investi- study in . California Fish and Game gation Proposal,Los Angeles County, California,USA. 61(1):4-25.

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REIMCHEN,T. 1998. Nocturnal foraging behaviour of black California.Bulletin of the SouthernCalifornia Academy of bears, Ursus americanus, on Moresby Island, British Sciences 93(1):30-37. Columbia.Canadian Field-Naturalist 112:446-450. VANSTRALEN, G. 1998. Home range size and habitatuse of SIPEREK,J., JR. 1979. Physicalcharacteristics and blood analysis urbanblack bears in southernCalifornia. Thesis, California State USA. of black bears (Ursus americanus) in the San Berardino University, Northridge,California, WESTERNREGIONAL CLIMATE CENTER. 2000. Historicalclimate Mountainsof southernCalifornia. Thesis, CaliforniaPoly- information.Period of record general climate summaries technic University,Pomona, California,USA. for Mount Wilson. Western Regional Climate Center, STEWART,G., J. SIPEREK,AND V. WHEELER.1980. Use of the Reno, NV, USA. http://www.wrcc.dri.edu,accessed De- anestheticCI-744 for chemicalrestraint of black cataleptoid cember 2000. bears.International Conference on Bear Researchand Man- WHITE,G., ANDR. GARROTT. 1990. Analysis of radio-tracking agement 4:57-61. data. Academic Press, Inc., , California,USA. Characteristicsof black bear STUBBLEFIELD,C. 1992. ecology ZAR,J. 1984. Biostatisticalanalysis. PrenticeHall, Englewood in the San Gabriel Mountains of southern California. Cliffs, New Jersey, USA. Thesis, California State Polytechnic University, Pomona, California,USA. Received: 25 February 2004 , ANDG. BRADEN.1994. Denning characteristicsof Accepted: 16 January 2004 black bears in the San Gabriel Mountains of southern Associate Editor: C. McLaughlin

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