Cryptic Behavior of Black Bears (Ursus americanus) in Rocky Mountain National Park, Colorado Author(s): Henry E. McCutchen Source: Bears: Their Biology and Management, Vol. 8, A Selection of Papers from the Eighth International Conference on Bear Research and Management, Victoria, British Columbia, Canada, February 1989 (1990), pp. 65-72 Published by: International Association of Bear Research and Management Stable URL: http://www.jstor.org/stable/3872903 Accessed: 02/01/2009 16:25 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=iba. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit organization founded in 1995 to build trusted digital archives for scholarship. We work with the scholarly community to preserve their work and the materials they rely upon, and to build a common research platform that promotes the discovery and use of these resources. For more information about JSTOR, please contact [email protected] International Association of Bear Research and Management is collaborating with JSTOR to digitize, preserve and extend access to Bears: Their Biology and Management. http://www.jstor.org CRYPTIC BEHAVIOR OF BLACKBEARS(URSUSAMERICANUS) INROCKY MOUNTAIN NATIONAL PARK,COLORADO HENRY E. MCCUTCHEN, Research Biologist, National Park Service, Rocky Mountain National Park, Estes Park, Colorado 80517 Abstract: Black bear (Ursus americanus) in many U.S. and Canadian national parks become habituated to humans. They are often bold, frequent human use areas and are generally a nuisance. At Rocky Mountain National Park, Colorado, the antithesis of this behavior has been observed in the black bear population. A 4-year study using radio-telemetry and observation indicates that although many bears have home ranges in high human use areas, they are secretive and avoid humans and developed areas. The behaviorof 2 of the park'sradio-collaredbears is documentedand discussed. Int. Conf. Bear Res. and Manage. 8:65-72 Most U.S. and Canadiannationalparkswith populations of Americanblack bears(Ursus americanus)have reportedproblemswiththis species. In partbecausethey are protectedin parks,bearshave become habituatedto humans,humanactivity, and development. They have tended to depend on humanfoods and refuse, and they have causedhumaninjuryandpropertydamagebecause of these unwantedhabits. Black bearsin most parksare highly visible and arecommonlyobservedby the public along roads, trails, and in campgrounds. Many parks have historicallyexperiencedhigh numbersof bearincidents anddepredations(Barnes 1967, Bray 1967, Marsh 1972,Peltonet al. 1976,ZardusandParsons1980,Harms 1979 and 1980, Singer and Bratton1980, Graber1981, Keay and VanWagtendonk1983, Herrero1985). Because of beardepredationsandhumaninjury,most nationalparkshave developedprograms,costly in funding and manpower, to mitigate or reduce black bear problems(Marsh 1972, Pelton 1972, Pelton et al. 1976, Harms1979 and 1980, Zardusand Parsons1980, Singer and Bratton 1980, Keay and VanWagtendonk1983). These include: educationalprogramsto teach parkvisitors and employees properbehaviorand food handling techniquesin regardto bears;establishmentandvigorous enforcement of rules and regulations relating to food handlinganddisposalandfeeding bears,andcaptureand transplantor removalof problembearsfromthe population. Expensive schemes to handle humanrefuse have been devised, such as installationof many bear-proof food containersandgarbagecans;closing openpitdumps; scheduling daily garbage pickups, and hauling refuse long distances out of the parks. These measures have significantlyreducedthe numbersof bear incidentsand bear-related human injuries over the past 15 years. However,manyparksstill have manybearincidentsand depredations. The blackbearsituationat Rocky MountainNational Park,Coloradocontrastswiththatof theotherparks.The parkhas a small black bearpopulationand althoughthe area is predominatelyforested and receives 2.5 million visitorsduringmostyears,depredationsorincidentshave been few to non-existent. Therehas seldom been a need to destroyor transplanta bear. Further,black bears are rarelyobservedby parkvisitorsor employees. The park has never had to implementa majorbear management programor install bear-proofgarbage cans because of bears. In 1984 a researchprogramwas initiatedon the black bearsin the parkto determinetheirpopulationdynamics, status, and behavior. The bears here were generally found to be shy and secretive. Theirbehavioris similar to that of Europeanbrown bears (Ursus arctos) (Roth 1976 and 1977, Roben 1980, HuberandRoth 1986, Elgmork 1976 and 1987) ratherthan that of black bears in North American national parks (Marsh 1972, Pelton 1972,Peltonet al. 1976,ZardusandParsons1980,Harms 1980, Graber1981, Herrero1985, Hastingset al. 1986). This paperdescribesand documentsthe behaviorof the bears at Rocky MountainNationalPark. STUDY AREA Rocky MountainNationalPark,locatedin northcentralColorado,is 106,700ha in size. The park,established in 1915,lies alongtheContinentalDivide. Situatedabout 65 km northwestof Denver, a majormetropolitanarea, theparkpreservesone of themostruggedandspectacular reachesof the ColoradoFrontRange. The elevationsare high, rangingfrom 2,329 m to 4,345 m. There are over 100 mountainpeaks exceeding an elevation of 3,000 m. Most of the area is mountainouswith steep cliffs and rugged U-shapedvalleys formedby glaciers duringthe Pleistocene epoch. The climate is continental with a mean annual temperatureof 6 C and a mean annual precipitationof 41 cm at the lower elevations. Mean annualtemperaturesdecreaseandprecipitationincreases withanincreasein elevation(Stevens 1980). Thehighest precipitationoccurs in the spring in the form of heavy, 66 BEARS-THEIR BIOLOGY AND MANAGEMENT wet snow. In the summer,afternoonthunderstormsalso bringprecipitation. Abouttwo-thirdsof the parkis forested. At the lower elevations,from2,300 m to 2,700 m, is a mosaicof forests and grasslandswith meadows and ripariantypes along the floodplains and river bottoms. The forests contain standsof ponderosapine (Pinusponderosa),Douglas-fir (Pseudotsugamenziesii), aspen (Populus tremuloides), and lodgepole pine (Pinus contorta). On the more open slopes thereare standsof big sage (Artemisiatridentata) andbitterbrush(Purshiatridentata)as well as grassland containing mountainmuhly (Muhlenbergiamontana), needle-and-thread(Stipa comata) and sedges (Carex spp.). Wetmeadowscontaintimothy(Phleumpratense), tuftedhairgrass(Deschampsiacaespitosa)andKentucky bluegrass(Poa pratensis). Along the riversarestandsof willow (Salix spp.), narrowleaf cottonwood (Populus angustifolia)and birch(Betula glandulosa). At mid-elevations, from 2,700 m to 3,500 m, are subalpineassociationswith standsof Engelmannspruce (Picea engelmannii)andsubalpinefir (Abieslasiocarpa) with an understoryof whortleberry(Vaccinium spp.). Lodgepolepine is presenton areasof shallow soil andin old burs. Limberpine (Pinusflexilis) and aspen stands are also presentin some sites. The upperelevations, above 3,500 m, containalpine tundra. Tundrais fairly extensive in the parkcovering aboutone-thirdof the area. Vegetationconsists of tufted hairgrass,sedges, Mt.Washingtondryad(Dryasoctopetala), cliff sedge (Carex scopulorum), Parry primrose (Primulaparryi), kobresia(Kobresiamyosuroides)and golden avens (Geumrossii). The area had a long history of land use before its establishmentas a nationalpark. Settlersbeganto arrive in the 1860's. Many areas in the park were farmed, mined, logged, and burned. Large rancheswere established and there was heavy grazing by domestic livestock. Because of its scenic beauty, the area was also recognizedfor its recreationalopportunities,whichled to the earlydevelopmentof duderanchesandresorts. In the earlydays the areawas notedfor its good hunting. Large ungulates, including elk (Cervus elaphus), mule deer (Odocoileushemionus)and bighornsheep (Ovis canadensis) wereextremelyabundant(Stevens 1980). Wolves (Canis lupus), grizzly bears (Ursus arctos), and black bears were present, but not as common as ungulates (Armstrong1975). Loss of habitat,local hunting,and markethuntersfrom Denver reducedthe ungulateherds so that by the turn of the century the elk had been extirpated(Sprague 1925, Stevens 1980). The bighorn populationspersisted but declined drasticallypossibly from scabies and loss of winter range in the 1930's (Wrightet al. 1932). The wolf becameextinctin theearly 1900's and the grizzly by the late 1920's (Wrightet al. 1932, Armstrong1975). The black bear survivedthese humanimpactsbut in low numbers(Wrightet al. 1932). In 1915, after 15 years of effort by conservationists,the areawas establishedas a nationalpark. Since then, a majoreffort in managingthe parkhas been aimed at restoringthe area to naturalconditions frompast land uses. Farms,ranches,homes, andresorts within the park boundary were purchasedand razed. Disturbedareaswere revegetatedor allowed to revegetate naturally. Criticalungulate winter range was purchasedandrestored.Elk andbighornsheepwerereintroduced and have shown impressive increases (Stevens 1980, Stevens and Hanson 1986). The presence of the park now dominates the local economy. Tourism has become the major business. Tourismanddevelopment,particularlyalong the eastern boundary,has increasedto the point thatit threatensthe integrityof the park. The gatewaytown of Estes Parkto the east has expanded to the park boundary. Dude ranches,condominiums,conferencecenters,andprivate homes areincreasingin numberseveryyear. Fortunately the areas adjacent to the north, west, and south park boundaries are primarily public lands where human developmentanduse is controlled.Huntingforbearsand otherwildlife species occurs outside the parkboundary. Regionally, urbanizationis occurring at a rapid pace along the FrontRangelowlandsnorthof Denverandeast of the park. Rocky Mountainis one of the most heavily used U.S. nationalparkswith 2.6 million visits in 1987,down from 3 million in 1978 (Rocky MountainNationalParkFact Sheet, Oct. 1988). The parkreceives morevisitationthan Yellowstone, yet is only one-eighth the size. Day use predominates;however, there are over 300,000 camper nights annually at the 5 campgrounds(Statementfor Management, 1982, Rocky Mountain National Park). Use is highly seasonal with the bulk occurringduring June, July, and August. Over 75% of the visitor use is concentratedon the east side of the ContinentalDivide in the park(MasterPlan, 1976, Rocky MountainNational Park). There are 250 backcountrycamp sites with an annualuse of about35,000 usernights,downfroma peak of 62,000 in 1977 (Statementfor Management,1982, Rocky MountainNational Park). Day hikeruse is also high,estimatedatabout600,000 peryearon the300 miles of parktrails(Statementfor Management,1982, Rocky IN ROCKYMOUNTAIN NATIONALPARK * McCutchen BLACKBEAR BEHAVIOR MountainNational Park). Commercialhorse rides are estimatedat 40,000 to 50,000 per year originatingfrom 2 liveries in the parkand 24 outside. Automobiletraffic is heavyon thepark's100mile$of roadsduringpeakdays of visitoruse. TrailRidgeRoad,whichtraversesfromthe east side to the west side of the park,can receive more than 1,000 cars per hour use during peak periods (McCutchenunpubl.data). To alleviate trafficcongestion to Bear Lake, anotherfavored area, a shuttle bus system is in operationduringthe summer. Blackbearsarepresentin theparkbuthaveneverbeen considered common (Armstrong 1975). Currentresearchindicatesthatthe populationin the parkis 30 to 35 bearswith about 1 bearper 30 km2(McCutchenunpubl. data).Thebearpopulationin theparkis viewed as a "high elevation"subpopulationcontiguouswith a largerpopulation of "low elevation" bears surroundingthe park. Becausethebearsaresecretive,theyareseldomobserved by the manyvisitorsusing the roadsandtrails. Bearscat and feeding sign is seldom seen in or near visitor use areas. Althoughbears have access to garbagecans and dumpsters(whicharenotbear-proofed),as well as campgrounds, picnic grounds, and backcountrycampsites, there is seldom an incident of a bear raiding them (McCutchenunpubl.data). A review of the historic records suggests that bear incidentsaresomewhatperiodicin the park(McCutchen unpubl.data). Bear incidentswere low in the late 1950's and early 1960's. During the 1960's there were 2 high years, 1963 and 1967, with 45 and 27 incidents,respectively. From 1959 to 1967 there were about 2 control actionsperyear with bears(14 transplantedand2 killed) in the park. From 1968 to 1983 therewere only 17 bear incidents for a rate of 1 per year. Three bears were capturedandtransplantedin controlactions. The reasons for the 2 years of high incident rates in the 1960's as comparedto the 1970's and early 1980's is not known. Visitation in 1962 was 1.7 million increasing to 2.5 million in 1972, then staying fairly constant (National ParkService 1976). Thus, visitationand bear incidents do not seem to be correlated.The reductionof incidents afterthe 1960's may be relatedto the purchaseandrazing of a numberof private guest ranches within the park, whichhadopenpitdumpsusedby bears,andbearcontrol in theparkatthattime (D. Stevens1989,RockyMountain NationalPark,pers. commun.). In 1984, aftera 17-year hiatus, anotherexceptional year occurredwhen a bear began to raid backcountrycampsites. That year there were about90 incidents. The offendingbear,a subadult male, was captured and removed from the area. In subsequentyears bear incidentswere again low. 67 MATERIALSAND METHODS Between 1984 and 1988, we captured23 black bears in the parkwith culverttrapsor with Aldrichfoot snares. We immobilizedthem with a combinationof Ketamine and Rompun. They were markedwith numberedaluminum ear tags, weighed, and measured. The first premolarwas pulled for cementumaging. Seventeenof the bears were radio-collared(Telonics, Mesa, AZ). Radio-telemetrywas conductedon foot, by automobile, by fixed-wingaircraft,andby helicopter.An attemptwas madeto obtainat least one accuratelocationon each bear each week. The usualprocedurewas to obtaina general location on a bear by vehicle then move in on foot to obtaina more accuratefix througha series of triangulations. It was extremely difficult to approachto within about 100 m of the bears without disturbingthem and chasing them away. Because of this, researcherswould often stay back about400 m or moreto obtainfixes. We estimatedthatradio-fixesobtainedat 100 m or less were accurateto about?25 m. Radio-fixes500 m to 1 km were accurateto about +150 m. Radio-locationswere only obtaineddiurnallyas nighttimelocations were too difficult to obtainin the ruggedterrain. Afterthebearresearchbegan,theparkstaffdeveloped a bearinformationnetwork. All bearsightingsreported by parkpersonnel(75 permanentand300 seasonals)and park visitors were channeled into a central dispatch office, recorded,then passed on to the researchteam. Becausebearswererare,parkvisitorsoften stoppedatthe entrancestationsor visitorcentersandreportedtheirbear sightings. Backcountryrangersreportedbear sightings or signs. Garbagehandlersreportedbearor otheranimal raidson garbagecans along theirroute. Forthis reportthe 2-yearcompositehome rangesand radio-locationsof 2 female bearsfor the years 1985and 1986areexamined. These arebearsNo. 2 with 47 radiolocations,andNo. 3 with 52 radio-locations.BearNo. 2 was estimatedto be 14-years-oldin 1985. Shehadno cubs in 1985and lost her cubs in the springof 1986. Bear No. 3 was estimatedto be 4-years-old in 1985. She had no cubs eitheryear. These bearswere selectedbecausethey had home ranges in the portion of the park with the greatesthumanuse. Duringthese time periods,no otherbearswereknown to be permanentresidentsin these bears' home ranges; however, different bears, believed to have been transients, were sighted in the area. Snarelines were set to determineif other bears were present. None were capturedexcept the known females. The relocationdatawere lumpedfor 1985and 1986to increase the sample sizes for statisticalanalyses and to 68 BEARS-THEIR BIOLOGY AND MANAGEMENT show the radio-locationsand home ranges on a single map. The 2 bearswere capturedin the summerof 1985, so thatyear's datawere only for a partof the summerand fall. The 1986 radio-locationdataarefor the entireyear. Theresultant2-yearcompositehomerangesandsizes for the 2 bears are similar to those obtainedthroughmore limited radio-trackingin 1987 and 1988 (McCutchen unpubl.data). To provide a measurementof each bear's avoidance behavior in relation to human use, radio-locationdata wereplottedon a base map. Thedistanceof each location to the closest set of humanuse featureswas then measuredto the nearest0.1 km. Humanuse featuresI believed to be of importanceincluded trails, trailheads,paved roads,dirtroads, humanresidences,picnic areas,major campgrounds,backcountrycampgrounds,theparkboundary, and miscellaneous developments (ski area, major pullouts, parkinglots, visitor centers, stables). Home rangeswere delimitedby the minimumpolygon method (Mohr1947). RESULTS AND DISCUSSION Figure 1 depictsthe 2-yearcompositehome rangesof bears No. 2 and 3. The home ranges overlappedonly slightly. Adult females in the park appearedto have nearlyexclusive homeranges(McCutchenunpubl.data), andmay be territorial,similarto the blackbearsreported by Young and Ruff (1982)and Rogers (1987). Bear No. 2 had a home range (70.8 km2) that was roughly boundedby Trail Ridge Road to the north,the main park road to the east, the Bear Lake Road to the south, and timberlineto the west (Fig. 1). Within her home rangewere approximately17 km of roads, 59 km of trails,11backcountrysites, 9 trailheads,2 majorpicnic grounds,a majorcampground,a majoroverlook,2 major parkinglots, and 1 smallresidentialarea. Along theroads were about 10 small pullouts and picnic tables with attendantgarbagecans. BearNo. 2 occasionallycrossedthe roadsto the north and southbut was never known to cross the roadsto the east. The greaterportionof her home range was in the backcountry,accessible only by trails. She frequently usedthe northwesternsectionof herhome rangecontaining ForestCanyon,a nearly impassablerugged area,of dense spruce/firforest and deadfall containingno trails. Her home range was away from areas of majorhuman development,particularlythe areato the east of her. This areaincludestheTown of EstesParkoutsidethe parkand an intensivezone of developmentin the parkcontaining 2 majorcampgrounds,a network of major roads, park severalresidentialareas,anda visitorcenter. headquarters, Althoughcampgroundsarean attractantto bearsin many nationalparks(Martinka1974, Peltonet al. 1976, Harms 1979 and 1980, Graber1981, Herrero1985), bearNo. 2 was never known to visit the campgrounds. The distanceof bearNo. 2's radio-locationsto visitor use areas (Fig. 2a) indicates that although she stayed away from these areas, the average distance was quite variabledependinguponthe areatype. Muchof herhome rangewas dissectedby trails;thus,she was locatedcloser to trails(0.8 km) and trailheads(1.9 km) on the average thanotherareasof use. Based on locations in her home range(Fig. 1) she seemed to be electing to be neartrails in the southernpart,apparentlyfor 2 reasons. First,trails in this areaarenearcreeksandwet areas,which,frommy experience, appearto be favored bear habitat. Second, there is some researchbias here as her signal was more easily picked up along trails than in "deadspots"away from trails. Bear No. 2 was seldom located in or near areasof majordevelopmentwhere humanuse and residence was on a 24-hourbasis or was year-round,e.g., the majorcampgrounds,andtheparkboundaryarea(Fig. 2a). Bear No. 3 had a smaller home range of 35.1 km2 (Fig. 1), which was dissected by 2 major roads, Trail Ridge Roadto the southandFall RiverRoadthroughthe valley in the center. Both of these roadsreceived heavy human use in the summer. Bear No. 3's home range contained24 kmof roads,9 kmof trails,a ski area,a major overlook, 6 large pullouts, 3 trailheads, and a small residentialarea. In addition,a majorpicnic groundwas located almost in the geographic center of her home range. At the pulloutsandotheruse areaswerenumerous garbagecans for the visitors' convenience. Bear No. 3's home range overlappedonly slightly withbearNo. 2's. BearNo. 3 tendedto utilizetherugged, steep, mountain slopes north and south of Fall River, particularlythenorth-facingslope withits denservegetation. Figure2b indicatesthatshe also was radio-located away fromareasof humanuse. She was locatedcloser to thepavedroadsthanotherfeaturesbutstill maintainedan averagedistanceof 1.1 km from them. She maintained the farthestdistanceaway from the nearestmajorcampground(6.0 km) and the parkboundary(6.5 km) to the east, on the average(Fig. 2b). She was never known to visit the picnic groundin the center of her home range even though it had dumpstersand garbage cans. In addition to the radio-telemetry,indirect evidence of avoidancewas determinedfromthe lack of any reported bear-raidingof the refuse containersin this area during thattime period. Figures 2a and 2b provide a rough index of the BLACK BEAR BEHAVIOR IN ROCKY MOUNTAIN NATIONAL PARK * McCutchen 3414 m ~/L approx. timberline , C, 3292 m NORTH 0 1000 2000 1000 4000 3000 5000 metersI Rocky Mountain National Park Boundary paved road dirt road bear #2 location bear #2 home range boundary bear #3 location bear #3 home range boundary areas of high human use park headquarters backcountry campsite trailhead trail *o o o H A * campground picnic area A I major stopping point ski area residence urban development X Fig. 1. Two-year composite s home ranges of black bears No. 2 and No. 3 (1985-1986) in relation to human use areas, Rocky Mountain National Park, Colorado. 69 70 BEARS THEIR BIOLOGY AND MANAGEMENT 13 12 FEMALE #2 11 | CONFIDENCE INTERVAL (95%) 10 I MEAN E RANGE LU z HC/) 9 EE 8 z 0 LL 0 z 7 6 c) o z o O o 0 4 0 C 2 I I 1 0 w _J - C a Q 0 >-"'i cc O m 0 o o Q a. I o zSi O() ZWO C Cc z --)z LU < C) 0 -rcis 0. cc -K v>. YE < 0 z ac I 0 5 : HUMAN USE FEATURES 4:j 0 Q ! - 1C 5 Ic >-Lu cc w I < >- a ( I Z _ 0 f) 0 ZW I a. co c w I C ca HUMAN USE FEATURES Figs. 2aand 2b. Radio-location distances of black bears No. 2 (N= 47) and No. 3 (N= 52) from human use features (1985-1986), Rocky Mountain National Park, Colorado. toleranceof bothbearsto variousparkrecreationaldevelopments. The various linear transportationcorridors (trailsandroads)were moretoleratedthanstructuresand facilities. Bear No. 2 was located closer to trailsthanto any other type of area probablybecause there were so many in her home range. Bear No. 3 was located closer to paved roads. Althoughpaved roadstendedto receive much greateruse than dirt roads, both bears seemed to toleratepaved roads slightly betterthan the dirtroads. The bears tended to keep about 1.5 to 4 km on the average from trailheads,human residences, and picnic grounds. They stayed the farthest, over 4 km on the average, from the major campgrounds. These average distances(Figs. 2a and2b) illustratea few generaltrends. Avoidance behavior of the bears is shown by the minimum distance the bears were located from human use areas (Figs. 2a and 2b). From the minimum distance statistics, other than the instance of bear No. 3 being locatedalong a trail,bothbearswerealways locatedaway from areasof humanuse. I hypothesizethatsimilardata developed for a bear habituatedto a campgroundor roadsidewould show a closer mean distanceand a minimum distance of zero as comparedto a non-habituated bear showing a farther mean distance and minimum distance greaterthan zero. Black bears have been known to stay away from humanuse areas duringthe day and visit them at night (Ayreset al. 1986) to obtainfood. Therewas no evidence that bears No. 2 and 3 did this. Thatthe bearsdid not use visitoruse areasat nightcan be inferredin several ways: they were not observed at night along roads and trails nor in the frontcountryor backcountrycampsitesby the numerousparkvisitors or by rangerson patrol;bear scat was rarely observed on trailsby the bearresearchteam or backcountryrangers; and the numerousgarbage cans placed along the roads and in picnic groundsand campgroundswere not raided at night. The crypticbehaviorof the bearsin the parkcan also be shown by the small numberof sightingsandincidents during 1985 and 1986 (Table 1). An incident was recordedwhen a bear was observed in a visitor use area foraging for human food or when a garbage can was raidedby a bear. In 1985 therewere 16 bearsightingsand 1 incidentparkwide. Of these, 7 were sightings in bear No. 2's home rangeand 1 was a sightingin bearNo. 3's. Most of these sightings within the home ranges were of the radio-collaredbears;however, a large, differentbear was sighted once in bearNo. 2's home range,duringthe breedingseason. It was most likely a male becausebear No. 2 had cubs the following season. In 1986 (Table 1), there were 13 sightings and 4 BLACKBEAR BEHAVIOR IN ROCKYMOUNTAIN NATIONALPARK * McCutchen incidents parkwide. There were 2 sightings and 1 incident in bear No. 2's home range and 2 sightings and no incidentsin bearNo. 3's. Again throughradio-tracking follow-up, the sightings were.most likely of the radiocollaredbears. The 1 incident,however, was caused by a transientbear. Consideringthatthe bulk of the visitor use in the park is in bear No. 2 and bear No. 3's home ranges, including the estimated 600,000 hiker-daysof trailuse, the numberof sightings is small. The most graphicdemonstrationof the level of avoidance of these females to human use areas occurredin 1985-1986. In the summerof 1985,bearsNo. 2 andNo. 3 werecaptured.BearNo. 2 weighed49 kg andbearNo. 3, capturedin late summer,weighed 35 kg. In the winterof 1985-1986they were reweighedat the dens. Bear No. 2, who had 2 cubs, still weighed 49 kg, and bear No. 3 weighed only 25 kg. In the summerof 1986 bearNo. 2 was recapturedand weighed 71 kg. I suspect thatthese weightlosses duringthe winterof 1985-1986wereattributedto a poorfood year in 1985. BearNo. 2 lost hercubs and I suspect that she was in such poor condition at a weight of 49 kg that she could not provide adequate nutritionfor them. Also for that winter,bearNo. 3 lost about26%of her summerweight. Neitherof these bears raidedreadilyavailablegarbagecans along roadsand in picnic areas or human food in backcountrycampsites before or after this apparentlydifficult denning period. The study team could only ask "Whywould these bears risk starvationin the den ratherthan forage on readily available,highenergy,humanfoodsintheirhomeranges"? The datapresentedabove suggest thatblack bears in this park exhibit a "model" behavior that many other parksare strivingfor. Yet, this "model"behaviorexacts a cost from the bears althoughthey are persistingin an areaof high humanuse. In the parkthereis a networkof humanuse travelcorridorsandcentersof highhumanuse with readily available high proteingarbage. There are even humanuse areasin whatwe perceiveas qualitybear habitat(riparianareas,aspen stands),yet the bearsavoid Table 1. Black bear sightings National Park, Colorado. and incidents, 1985 and1986, Rocky Mountain Sightings 1985 1986 Home ranges bearNo. 2 bear No. 3 Otherareas Total 7 1 2 2 Incidents 1985 1986 0 0 1 0 8 9 1 3 16 13 1 4 71 these areas and utilize the intersticeswithin the human use web. Researchersof blackbearsandgrizzlies in some parks have noted 2 types of behaviorin the same population, dependingupon whetheror not they visited humanuse areasfor food. For grizzlies in Yellowstone, Mattsonet al. (1987) labeled these types "wary"and "habituated". Ayres et al. (1986) separatedthe black bears in Sequoia NationalParkinto"natural" and"campgroundbears".At Rocky MountainNationalParkthe blackbears,withrare exception, would be classified as "wary"or "natural". Thereis no evidenceof"habituation"(McArthur1983)at the presenttime. Parkswith a historyof artificialfeedingof bears,such as Yellowstone, Sequoia and Kings Canyon, Yosemite, and the GreatSmoky Mountains,have persistingproblems with habituatedbears, even with intensive bear managementprogramsin place overthepast 15years. At Rocky Mountainbears were never allowed to feed on humanfoods (Wrightet al. 1932). Fromthe time the park was establishedin 1915,bearsthatdevelopedthe habitof feeding on humanfoods were removed from the park. Martinka(1972) notes that this was the case in Glacier National Park. Yet, Glacier regularlyhas problems if food is unsecured. Black bears commonly enter campgrounds,picnic areasandotherdevelopedareas,andoccasionally obtainunsecuredfood. Elgmork (1976, 1987) suggested that the cryptic behaviorof brown bears in Norway may have been the result of historic overhuntingand "gun selection". He hypothesizedthatthis traitcould be passedon via heredity andlearningto new generations.Perhapsheredityand learninghaveinfluencedRockyMountainNationalPark's blackbearsbecausethey were heavilyhuntedpriorto the park's establishment. Also, the park is so small that nearlyevery bearmay be exposed to huntingadjacentto the parkboundaryduringits lifetime, even thoughthey areprotectedin the park.Two of the bearsradio-collared in the park(subadultmales) have been killed by hunters outside the park. An additionalfactormay be the selective pressureof the removal of problembears that has been maintained on the small population of Rocky Mountainbearssince the parkwas establishedin 1915. At thepresenttimethereasonorreasonsforthecryptic behaviorof the blackbearsat Rocky MountainNational Parkwill continueto be investigated.Followingthebears for severalgenerationsmayprovidesome insightintothe behavior;however,thisphenomenonmayneverbe easily explained. The behaviormay be the result of genetics, learning,or a combinationof these. Otherinterrelated factors might include a history of huntingpriorto park 72 BEARS-THEIR ANDMANAGEMENT BIOLOGY establishment; National Park Service control actions; a lack of widespread historical artificial feeding; low population densities with an inability to fill available vacant habitat; low rates of reproduction; loss of habitat; and poor quality, interspersion, andjuxtaposition of resources. Whatever the reasons, these bears apparently give up valuable habitat to the more dominant species, man, within their own home ranges. LITERATURE CITED D.M. 1975. Rocky Mountainmammals. Rocky ARMSTRONG, MountainNatureAssoc. Inc. EstesPark,Colorado.174pp. AYRES,L.A., L.S. CHOW,ANDD.M. GRABER.1986. Black bear activity patternsand humaninducedmodificationin Sequoia National Park. Int. Conf. Bear Res. and Manage. 6:152-154. BARNES,V.G., JR. 1967. Activities of black bear. M.S. Thesis, Colo. State Univ., Ft. Collins. 116pp. O.E. 1967. Populationstudyof blackbear. M.S. Thesis, BRAY, Colo. State Univ., Ft. Collins. 97pp. K. 1976. A remnant brown bear population in ELGMORK, Norwayandproblemsof its conservation.Int.Conf. Bear Res. and Manage. 3:281-292. . 1987. The crypticbrownbearpopulationof Norway. ___ Int. Conf. Bear Res. and Manage. 7:13-16. D.M. 1981. Ecology andmanagementof blackbears GRABER, in Yosemite National Park. Ph.D. Thesis, Univ. Calif., Berkeley. 206pp. D.R. 1979. Nationalparks- 1976. Pages 135-146 in HARMS, D. Burk, ed. The black bear in moder North America. Boone and Crocket Club. Amwell Press, Clinton, N.J. 300pp. _ . 1980. Black bear managementin Yosemite National Park. Int. Conf. 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