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Cryptic Behavior of Black Bears (Ursus americanus) in Rocky Mountain National Park, 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, , 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

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http://www.jstor.org CRYPTICBEHAVIOR OF BLACKBEARS (URSUS AMERICANUS) IN ROCKY MOUNTAINNATIONAL 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- 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's radio-collaredbears is documentedand discussed.

Int. Conf. Bear Res. and Manage. 8:65-72

Most U.S. and Canadiannational parks with popula- area is predominatelyforested and receives 2.5 million tions of Americanblack bears (Ursus americanus)have visitorsduring most , depredations or incidentshave reportedproblems with this . In partbecause they been few to non-existent. Therehas seldom been a need are protectedin parks,bears have become habituatedto to destroy or transplanta bear. Further,black bears are humans, humanactivity, and development. They have rarelyobserved by parkvisitors or employees. The park tended to depend on human foods and refuse, and they has never had to implement a major bear management have caused humaninjury and propertydamage because programor install bear-proofgarbage cans because of of these unwantedhabits. Black bearsin most parksare bears. highly visible and are commonly observedby the public In 1984 a researchprogram was initiatedon the black along roads, trails, and in campgrounds. Many parks bearsin the parkto determinetheir population dynamics, have historicallyexperienced high numbersof bearinci- status, and behavior. The bears here were generally dents and depredations(Barnes 1967, Bray 1967, Marsh found to be shy and secretive. Their behavioris similar 1972, Peltonet al. 1976,Zardus and Parsons 1980, Harms to that of Europeanbrown bears (Ursus arctos) (Roth 1979 and 1980, Singer and Bratton 1980, Graber1981, 1976 and 1977, Roben 1980, Huberand Roth 1986, Elg- Keay and VanWagtendonk1983, Herrero1985). mork 1976 and 1987) ratherthan that of black bears in Because of beardepredations and human injury, most North American national parks (Marsh 1972, Pelton nationalparks have developed programs,costly in fund- 1972,Pelton et al. 1976, Zardusand Parsons 1980, Harms ing and manpower, to mitigate or reduce black bear 1980, Graber1981, Herrero1985, Hastingset al. 1986). problems(Marsh 1972, Pelton 1972, Pelton et al. 1976, This paperdescribes and documentsthe behaviorof the Harms 1979 and 1980, Zardusand Parsons 1980, Singer bears at Rocky MountainNational Park. and Bratton 1980, Keay and VanWagtendonk 1983). These include: educationalprograms to teach parkvisi- tors and employees properbehavior and food handling STUDY AREA techniquesin regardto bears;establishment and vigorous Rocky MountainNational Park, located in northcen- enforcement of rules and regulations relating to food tralColorado, is 106,700 ha in size. The park,established handlingand disposal and feeding bears,and capture and in 1915, lies alongthe ContinentalDivide. Situatedabout or transplant removalof problembears from the popula- 65 km northwestof Denver, a majormetropolitan area, tion. schemes Expensive to handle humanrefuse have the parkpreserves one of the most ruggedand spectacular been devised, such as installationof many bear-proof reachesof the ColoradoFront Range. The elevationsare food containersand garbage cans; closing openpit dumps; high, rangingfrom 2,329 m to 4,345 m. There are over scheduling daily garbage pickups, and hauling refuse 100 mountainpeaks exceeding an elevation of 3,000 m. distances out of the long parks. These measures have Most of the area is mountainouswith steep cliffs and reducedthe numbersof significantly bear incidentsand rugged U-shapedvalleys formed by glaciers duringthe bear-related human injuries over the past 15 years. epoch. The climate is continental with a However,many parksstill have many bearincidents and mean annual temperatureof 6 C and a mean annual depredations. precipitationof 41 cm at the lower elevations. Mean The black bear situationat Rocky MountainNational annualtemperatures decrease and precipitation increases Colorado Park, contrastswith thatof the otherparks. The withan increasein elevation(Stevens 1980). The highest has a small black park bear populationand althoughthe precipitationoccurs in the spring in the form of heavy, 66 BEARS-THEIR BIOLOGY AND MANAGEMENT

wet snow. In the summer,afternoon thunderstorms also populationspersisted but declined drasticallypossibly bring precipitation. from scabies and loss of winter range in the 1930's About two-thirdsof the parkis forested. At the lower (Wrightet al. 1932). The becameextinct in the early elevations,from 2,300 m to 2,700 m, is a mosaic of forests 1900's and the grizzly by the late 1920's (Wrightet al. and grasslandswith meadows and ripariantypes along 1932, Armstrong1975). The black bear survived these the floodplains and river bottoms. The forests contain humanimpacts but in low numbers(Wright et al. 1932). standsof ponderosapine (Pinusponderosa),Douglas-fir In 1915, after 15 years of effort by conservationists,the (Pseudotsuga menziesii), aspen (Populus tremuloides), area was establishedas a nationalpark. and lodgepole pine (Pinus contorta). On the more open Since then, a major effort in managing the park has slopes thereare standsof big sage (Artemisiatridentata) been aimed at restoring the area to naturalconditions and bitterbrush(Purshia tridentata)as well as grassland from past land uses. Farms,ranches, homes, and resorts containing mountain muhly (Muhlenbergiamontana), within the park boundary were purchased and razed. needle-and-thread(Stipa comata) and sedges (Carex Disturbedareas were revegetatedor allowed to revege- spp.). Wet meadowscontain timothy (Phleumpratense), tate naturally. Criticalungulate winter range was pur- tuftedhairgrass (Deschampsia caespitosa) and Kentucky chasedand restored. andbighorn were reintro- bluegrass(Poa pratensis). Along the riversare standsof duced and have shown impressive increases (Stevens willow (Salix spp.), narrowleaf cottonwood (Populus 1980, Stevens and Hanson 1986). angustifolia) and birch (Betula glandulosa). The presence of the park now dominates the local At mid-elevations, from 2,700 m to 3,500 m, are economy. Tourism has become the major business. subalpineassociations with standsof Engelmannspruce Tourismand development, particularly along the eastern (Picea engelmannii)and subalpine fir (Abieslasiocarpa) boundary,has increasedto the point that it threatensthe with an understoryof whortleberry(Vaccinium spp.). integrityof the park. The gateway town of Estes Parkto Lodgepolepine is presenton areasof shallow soil and in the east has expanded to the park boundary. Dude old burs. Limberpine (Pinusflexilis) and aspen stands ranches,condominiums, conference centers, and private are also presentin some sites. homes areincreasing in numbersevery year. Fortunately The upperelevations, above 3,500 m, contain alpine the areas adjacent to the north, west, and south park tundra. Tundrais fairly extensive in the parkcovering boundaries are primarily public lands where human aboutone-third of the area. Vegetationconsists of tufted developmentand use is controlled. for bearsand hairgrass,sedges, Mt. Washingtondryad (Dryas octopet- other wildlife species occurs outside the parkboundary. ala), cliff sedge (Carex scopulorum), Parry primrose Regionally, urbanizationis occurring at a rapid pace (Primulaparryi), kobresia(Kobresia myosuroides) and along the FrontRange lowlands north of Denverand east golden avens (Geumrossii). of the park. The area had a long history of land use before its Rocky Mountainis one of the most heavily used U.S. establishmentas a nationalpark. Settlersbegan to arrive nationalparks with 2.6 million visits in 1987,down from in the 1860's. Many areas in the park were farmed, 3 million in 1978 (Rocky MountainNational ParkFact than mined, logged, and burned. Large ranches were estab- Sheet, Oct. 1988). The parkreceives morevisitation lished and there was heavy by domestic live- Yellowstone, yet is only one-eighth the size. Day use stock. Because of its scenic beauty, the area was also predominates;however, there are over 300,000 camper the 5 for recognizedfor its recreationalopportunities, which led to nights annually at campgrounds(Statement Mountain National the earlydevelopment of duderanches and resorts. In the Management, 1982, Rocky Park). with the bulk early days the areawas notedfor its good hunting. Large Use is highly seasonal occurringduring and Over 75% of the visitor use is ungulates, including elk ( elaphus), mule June, July, August. side of the ContinentalDivide in ( hemionus)and bighornsheep ( canad- concentratedon the east MountainNational ensis) were extremelyabundant (Stevens 1980). the park(Master Plan, 1976, Rocky 250 sites with an (Canis lupus), grizzly bears (Ursus arctos), and black Park). There are backcountrycamp user down froma bears were present, but not as common as ungulates annualuse of about35,000 nights, peak in for 1982, (Armstrong1975). Loss of habitat,local hunting, and of 62,000 1977 (Statement Management, markethunters from Denver reducedthe ungulateherds Rocky MountainNational Park). Day hiker use is also atabout on the 300 miles so that by the turn of the century the elk had been high,estimated 600,000 peryear for extirpated(Sprague 1925, Stevens 1980). The bighorn of parktrails (Statement Management,1982, Rocky BLACKBEAR BEHAVIORIN ROCKYMOUNTAIN NATIONAL PARK * McCutchen 67

MountainNational Park). Commercialhorse rides are MATERIALSAND METHODS estimatedat 40,000 to 50,000 per year originatingfrom Between 1984 and 1988, we captured23 black bears 2 liveries in the parkand 24 outside. Automobiletraffic in the parkwith culverttraps or with Aldrichfoot snares. is heavy on the park's 100 mile$of roadsduring peak days We immobilizedthem with a combinationof Ketamine of visitoruse. TrailRidge Road,which traversesfrom the and Rompun. They were markedwith numberedalu- east side to the west side of the park, can receive more minum ear tags, weighed, and measured. The first than 1,000 cars per hour use during peak periods premolarwas pulled for cementumaging. Seventeen of (McCutchenunpubl. data). To alleviate traffic conges- the bears were radio-collared(Telonics, Mesa, AZ). tion to Bear Lake, another favored area, a shuttle bus Radio-telemetrywas conductedon foot, by automobile, system is in operationduring the summer. by fixed-wing aircraft,and by helicopter.An attemptwas Black bearsare present in the parkbut have neverbeen madeto obtainat least one accuratelocation on each bear considered common (Armstrong 1975). Current re- each week. The usual procedurewas to obtaina general searchindicates that the populationin the parkis 30 to 35 location on a bear by vehicle then move in on foot to bears with about 1 bearper 30 km2(McCutchen unpubl. obtain a more accuratefix througha series of triangula- data). The bearpopulation in the parkis viewed as a "high tions. It was extremely difficult to approachto within elevation"subpopulation contiguous with a largerpopu- about 100 m of the bears without disturbingthem and lation of "low elevation" bears surroundingthe park. chasing them away. Because of this, researcherswould Because the bearsare secretive, they areseldom observed often stay back about400 m or more to obtainfixes. We by the many visitors using the roadsand trails. Bear scat estimatedthat radio-fixes obtained at 100 m or less were and feeding sign is seldom seen in or near visitor use accurateto about ?25 m. Radio-fixes500 m to 1 km were areas. Although bears have access to garbagecans and accurateto about +150 m. Radio-locationswere only dumpsters(which arenot bear-proofed),as well as camp- obtaineddiurnally as nighttimelocations were too diffi- grounds, picnic grounds, and backcountrycampsites, cult to obtain in the rugged terrain. there is seldom an incident of a bear raiding them Afterthe bearresearch began, the parkstaff developed (McCutchenunpubl. data). a bear informationnetwork. All bear sightings reported A review of the historic records suggests that bear by parkpersonnel (75 permanentand 300 seasonals)and incidentsare somewhatperiodic in the park(McCutchen park visitors were channeled into a central dispatch unpubl.data). Bear incidentswere low in the late 1950's office, recorded, then passed on to the research team. and early 1960's. During the 1960's there were 2 high Becausebears were rare, park visitors often stoppedat the years, 1963 and 1967, with 45 and 27 incidents,respec- entrancestations or visitorcenters and reported their bear tively. From 1959 to 1967 there were about 2 control sightings. Backcountryrangers reported bear sightings actions per year with bears(14 transplantedand 2 killed) or signs. Garbagehandlers reported bear or otheranimal in the park. From 1968 to 1983 there were only 17 bear raids on garbagecans along their route. incidents for a rate of 1 per year. Three bears were For this reportthe 2-yearcomposite home rangesand capturedand transplanted in controlactions. The reasons radio-locationsof 2 female bears for the years 1985 and for the 2 years of high incident rates in the 1960's as 1986are examined. These are bearsNo. 2 with 47 radio- comparedto the 1970's and early 1980's is not known. locations, and No. 3 with 52 radio-locations.Bear No. 2 Visitation in 1962 was 1.7 million increasing to 2.5 was estimatedto be 14-years-oldin 1985. She hadno cubs million in 1972, then staying fairly constant (National in 1985and lost her cubs in the springof 1986. Bear No. ParkService 1976). Thus, visitation and bear incidents 3 was estimatedto be 4-years-old in 1985. She had no do not seem to be correlated. The reductionof incidents cubs eitheryear. These bearswere selected becausethey afterthe 1960's may be relatedto the purchaseand razing had home ranges in the portion of the park with the of a number of private guest ranches within the park, greatesthuman use. which hadopen pit dumpsused by bears,and bear control Duringthese time periods,no otherbears were known in the parkat thattime (D. Stevens 1989,Rocky Mountain to be permanentresidents in these bears' home ranges; NationalPark, pers. commun.). In 1984, aftera 17-year however, different bears, believed to have been tran- hiatus, anotherexceptional year occurred when a bear sients, were sighted in the area. Snare lines were set to began to raid backcountrycampsites. That year there determineif other bears were present. None were cap- were about90 incidents. The offending bear,a subadult turedexcept the known females. male, was captured and removed from the area. In The relocationdata were lumpedfor 1985 and 1986 to subsequentyears bear incidents were again low. increase the sample sizes for statisticalanalyses and to 68 BEARS-THEIR BIOLOGY AND MANAGEMENT

show the radio-locationsand home ranges on a single headquarters,several residential areas, and a visitorcenter. map. The 2 bears were capturedin the summerof 1985, Althoughcampgrounds are an attractantto bearsin many so thatyear's datawere only for a partof the summerand nationalparks (Martinka 1974, Peltonet al. 1976, Harms fall. The 1986 radio-locationdata are for the entireyear. 1979 and 1980, Graber1981, Herrero1985), bearNo. 2 The resultant2-year composite home rangesand sizes for was never known to visit the campgrounds. the 2 bears are similar to those obtained throughmore The distanceof bearNo. 2's radio-locationsto visitor limited radio-trackingin 1987 and 1988 (McCutchen use areas (Fig. 2a) indicates that although she stayed unpubl.data). away from these areas, the average distance was quite To provide a measurementof each bear's avoidance variabledepending upon the areatype. Muchof herhome behavior in relation to human use, radio-locationdata rangewas dissectedby trails;thus, she was locatedcloser wereplotted on a base map. The distanceof each location to trails (0.8 km) and trailheads(1.9 km) on the average to the closest set of humanuse featureswas then meas- than other areasof use. Based on locations in her home uredto the nearest0.1 km. Humanuse featuresI believed range (Fig. 1) she seemed to be electing to be neartrails to be of importance included trails, trailheads,paved in the southernpart, apparently for 2 reasons. First,trails roads, dirtroads, humanresidences, picnic areas,major in this areaare near creeks and wet areas,which, frommy campgrounds,backcountry campgrounds, the park bound- experience, appearto be favored bear habitat. Second, ary, and miscellaneous developments (ski area, major there is some researchbias here as her signal was more pullouts, parking lots, visitor centers, stables). Home easily picked up along trails than in "deadspots" away rangeswere delimitedby the minimumpolygon method from trails. Bear No. 2 was seldom located in or near (Mohr 1947). areas of majordevelopment where humanuse and resi- dence was on a 24-hourbasis or was year-round,e.g., the majorcampgrounds, and the park boundary area (Fig. 2a). RESULTS AND DISCUSSION Bear No. 3 had a smaller home range of 35.1 km2 Figure 1 depicts the 2-yearcomposite home rangesof (Fig. 1), which was dissected by 2 major roads, Trail bears No. 2 and 3. The home ranges overlappedonly Ridge Road to the southand Fall RiverRoad throughthe slightly. Adult females in the park appearedto have valley in the center. Both of these roadsreceived heavy nearlyexclusive home ranges(McCutchen unpubl. data), human use in the summer. Bear No. 3's home range and may be territorial,similar to the black bearsreported contained24 km of roads,9 kmof trails,a ski area,a major by Young and Ruff (1982)and Rogers (1987). overlook, 6 large pullouts, 3 trailheads, and a small Bear No. 2 had a home range (70.8 km2) that was residentialarea. In addition,a majorpicnic groundwas of her home roughly boundedby Trail Ridge Road to the north, the located almost in the geographic center numerous main park road to the east, the Bear Lake Road to the range. At the pulloutsand other use areaswere south, and timberlineto the west (Fig. 1). Within her garbagecans for the visitors' convenience. home range were approximately17 km of roads, 59 km Bear No. 3's home range overlapped only slightly of trails, 11 backcountrysites, 9 trailheads,2 majorpicnic with bearNo. 2's. BearNo. 3 tendedto utilize therugged, north and south of Fall grounds,a majorcampground, a majoroverlook, 2 major steep, mountain slopes River, the with its denser parkinglots, and 1 smallresidential area. Along the roads particularly north-facingslope vegeta- radio-located were about 10 small pullouts and picnic tables with tion. Figure2b indicatesthat she also was use. She was locatedcloser to attendantgarbage cans. away fromareas of human maintainedan BearNo. 2 occasionallycrossed the roadsto the north the pavedroads than other features but still and south but was never known to cross the roads to the averagedistance of 1.1 km from them. She maintained from the nearest east. The greaterportion of her home range was in the the farthestdistance away majorcamp- and the to the backcountry,accessible only by trails. She frequently ground(6.0 km) parkboundary (6.5 km) used the northwesternsection of herhome rangecontain- east, on the average (Fig. 2b). She was never known to visit the in the center of her home range ing Forest Canyon, a nearly impassablerugged area, of picnic ground it had and cans. In dense spruce/firforest and dead fall containingno trails. even though dumpsters garbage the indirect evidence of Her home range was away from areas of major human addition to radio-telemetry, was determinedfrom the lack of development,particularly the areato the east of her. This avoidance any reported areaincludes the Town of Estes Parkoutside the parkand bear-raidingof the refuse containersin this area during an intensive zone of developmentin the parkcontaining that time period. 2a and 2b a index of the 2 major campgrounds,a network of major roads, park Figures provide rough BLACK BEAR BEHAVIOR IN ROCKY MOUNTAIN NATIONAL PARK * McCutchen 69

3414 m ~/L

approx. timberline ,

C,

3292 m

NORTH

0 2000 4000 1000 1000 3000 5000 metersI

Rocky Mountain National Park Boundary paved road dirt road bear #2 location bear #2 home range boundary *- bear #3 location o bear #3 home range boundary o o areas of high human use park headquarters H backcountry campsite A trailhead * trail campground A picnic area I major stopping point X ski area s residence urban development

Fig. 1. Two-year composite home ranges of black bears No. 2 and No. 3 (1985-1986) in relation to human use areas, Rocky Mountain National Park, Colorado. 70 BEARS THEIR BIOLOGY AND MANAGEMENT

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HUMAN USE FEATURES 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 bothbears to variouspark recreational devel- human use areas during the day and visit them at night opments. The various linear transportationcorridors (Ayres et al. 1986) to obtainfood. Therewas no evidence (trailsand roads) were more toleratedthan structures and that bears No. 2 and 3 did this. facilities. Bear No. 2 was located closer to trails than to Thatthe bearsdid not use visitor use areasat night can any other type of area probablybecause there were so be inferredin several ways: they were not observed at many in her home range. Bear No. 3 was located closer night along roads and trails nor in the frontcountryor to paved roads. Althoughpaved roads tended to receive backcountrycampsites by the numerouspark visitors or much greateruse than dirt roads, both bears seemed to by rangers on patrol; bear scat was rarely observed on toleratepaved roads slightly betterthan the dirt roads. trails by the bear researchteam or backcountryrangers; The bears tended to keep about 1.5 to 4 km on the and the numerousgarbage cans placed along the roads average from trailheads,human residences, and picnic and in picnic groundsand campgroundswere not raided grounds. They stayed the farthest, over 4 km on the at night. average, from the major campgrounds. These average The cryptic behaviorof the bears in the parkcan also distances(Figs. 2a and2b) illustratea few generaltrends. be shown by the small numberof sightings and incidents Avoidance behavior of the bears is shown by the mini- during 1985 and 1986 (Table 1). An incident was mum distance the bears were located from human use recordedwhen a bear was observed in a visitor use area areas (Figs. 2a and 2b). From the minimum distance foraging for human food or when a garbage can was statistics, other than the instance of bear No. 3 being raidedby a bear. In 1985 therewere 16 bearsightings and locatedalong a trail,both bears were always locatedaway 1 incident parkwide. Of these, 7 were sightings in bear from areasof humanuse. I hypothesize that similardata No. 2's home range and 1 was a sighting in bearNo. 3's. developed for a bear habituated to a campground or Most of these sightings within the home ranges were of roadsidewould show a closer mean distanceand a mini- the radio-collaredbears; however, a large, differentbear mum distance of zero as comparedto a non-habituated was sighted once in bearNo. 2's home range, duringthe bear showing a farther mean distance and minimum breedingseason. It was most likely a male because bear distance greaterthan zero. No. 2 had cubs the following season. Black bears have been known to stay away from In 1986 (Table 1), there were 13 sightings and 4 BLACKBEAR BEHAVIORIN ROCKYMOUNTAIN NATIONAL PARK * McCutchen 71 incidents parkwide. There were 2 sightings and 1 inci- these areas and utilize the intersticeswithin the human dent in bear No. 2's home range and 2 sightings and no use web. incidents in bear No. 3's. Again throughradio-tracking Researchersof blackbears and grizzlies in some parks follow-up, the sightings were.most likely of the radio- have noted 2 types of behavior in the same population, collaredbears. The 1 incident,however, was caused by dependingupon whetheror not they visited humanuse a transientbear. Consideringthat the bulk of the visitor areasfor food. For grizzlies in Yellowstone, Mattsonet use in the park is in bear No. 2 and bear No. 3's home al. (1987) labeled these types "wary"and "habituated". ranges, including the estimated 600,000 hiker-days of Ayres et al. (1986) separatedthe black bears in Sequoia trail use, the numberof sightings is small. NationalPark into "natural"and "campground bears". At The most graphicdemonstration of the level of avoid- Rocky MountainNational Park the blackbears, with rare ance of these females to human use areas occurred in exception, would be classified as "wary"or "natural". 1985-1986. In the summerof 1985,bears No. 2 andNo. 3 Thereis no evidence of"habituation"(McArthur 1983) at werecaptured. Bear No. 2 weighed49 kg andbear No. 3, the presenttime. capturedin late summer,weighed 35 kg. In the winterof Parkswith a historyof artificialfeeding of bears,such 1985-1986they were reweighedat the dens. Bear No. 2, as Yellowstone, Sequoia and Kings Canyon, Yosemite, who had 2 cubs, still weighed 49 kg, and bear No. 3 and the Great Smoky Mountains,have persistingprob- weighed only 25 kg. In the summerof 1986 bear No. 2 lems with habituatedbears, even with intensive bear was recapturedand weighed 71 kg. I suspect that these managementprograms in place over the past 15 years. At weight losses duringthe winterof 1985-1986 wereattrib- Rocky Mountainbears were never allowed to feed on uted to a poor food year in 1985. Bear No. 2 lost hercubs humanfoods (Wrightet al. 1932). Fromthe time the park and I suspect that she was in such poor condition at a was establishedin 1915, bearsthat developed the habitof weight of 49 kg that she could not provide adequate feeding on human foods were removed from the park. nutritionfor them. Also for that winter, bear No. 3 lost Martinka(1972) notes that this was the case in Glacier about26% of her summerweight. Neitherof these bears National Park. Yet, Glacier regularly has problems if raidedreadily availablegarbage cans along roadsand in food is unsecured. Black bears commonly enter camp- picnic areas or human food in backcountrycampsites grounds,picnic areasand otherdeveloped areas,and oc- before or after this apparentlydifficult denning period. casionally obtain unsecuredfood. The study team could only ask "Why would these bears Elgmork (1976, 1987) suggested that the cryptic risk starvationin the den ratherthan forage on readily behaviorof brown bears in Norway may have been the available,high energy, human foods in theirhome ranges"? result of historic overhuntingand "gun selection". He The data presentedabove suggest that black bears in hypothesizedthat this traitcould be passed on via hered- this park exhibit a "model" behavior that many other ity andlearning to new generations.Perhaps heredity and parksare strivingfor. Yet, this "model"behavior exacts learninghave influenced Rocky Mountain National Park's a cost from the bears althoughthey are persistingin an blackbears because they were heavily huntedprior to the areaof high humanuse. In the parkthere is a networkof park's establishment. Also, the park is so small that humanuse travelcorridors and centers of high humanuse nearlyevery bearmay be exposed to huntingadjacent to with readily available high protein garbage. There are the parkboundary during its lifetime, even though they even humanuse areasin whatwe perceiveas qualitybear areprotected in the park. Two of the bearsradio-collared habitat(riparian areas, aspen stands),yet the bearsavoid in the park(subadult males) have been killed by hunters outside the park. An additionalfactor may be the selec- tive pressureof the removal of problem bears that has Table 1. Black bear sightings and incidents, 1985 and1986, Rocky Mountain National Park, Colorado. been maintained on the small population of Rocky Mountainbears since the parkwas establishedin 1915. At the presenttime the reasonor reasonsfor the cryptic Sightings Incidents 1985 1986 1985 1986 behaviorof the black bearsat Rocky MountainNational Parkwill continueto be investigated.Following the bears Home ranges for severalgenerations may providesome insightinto the bear 2 No. 7 2 0 1 behavior;however, this phenomenon may never be easily bear No. 3 1 2 0 0 explained. The behaviormay be the result of genetics, Otherareas 8 9 1 3 learning,or a combinationof these. Other interrelated Total 16 13 1 4 factors might include a history of huntingprior to park 72 BEARS-THEIRBIOLOGY AND MANAGEMENT

establishment; National Park Service control actions; a _ . 1974. Preserving the natural status of grizzlies in Glacier National Park. Wildl. Soc. Bull. 13-17. lack of widespread historical artificial feeding; low popu- 2(1) MATTSON,D.J., R.R. KNIGHT,AND B.M. BLANCHARD.1987. lation densities with an inability to fill available vacant The effects of developmentsand primary roads on grizzly low rates of loss of and habitat; reproduction; habitat; bearhabitat use in Yellowstone NationalPark, Wyoming. poor quality, interspersion, and juxtaposition of resources. Int. Conf. Bear Res. and Manage. 7:259-273. Whatever the reasons, these bears apparently give up NATIONALPARK SERVICE. 1976. Final master plan, Rocky MountainNational Park. valuable habitat to the more dominant species, man, 40pp. MCARTHURJOPE, K.L. 1983. Habituation of grizzly bears to within their own home ranges. people: a hypothesis. Int. Conf. Bear Res. and Manage. 5:322-327. MOHR,C.O. 1947. Table of equivalentpopulation on North LITERATURECITED Americanmammals. Am. Midi. Nat. 37:223-247. D.M. 1975. Mountainmammals. ARMSTRONG, Rocky Rocky PELTON,M.R. 1972. Use of foot trail travelersin the Great MountainNature Assoc. Inc. EstesPark, Colorado. 174pp. Smoky MountainsNational Park to estimate black bear AYRES, L.S. ANDD.M. GRABER.1986. Black bear L.A., CHOW, (Ursus americanus) activity. Int. Conf. Bear Res. and activity patternsand humaninduced modificationin Se- 2:36-42. National Park. Int. Conf. Bear Res. and Manage. quoia Manage. , C.D. Scorr, ANDG.M. BURGHARDT.1976. Attitudes 6:152-154. and opinions of persons experiencing propertydamage BARNES,V.G., JR. 1967. Activities of black bear. M.S. Thesis, and/or injuryby black bears in the Great Smoky Moun- Colo. State Univ., Ft. Collins. 116pp. tains National Park. Int. Conf. Bear Res. and Manage. BRAY,O.E. 1967. Populationstudy of blackbear. M.S. Thesis, 3:152-168. Colo. State Univ., Ft. Collins. 97pp. ROBEN, P. 1980. Statusof the brownbear in the Pyrenees. Int. ELGMORK,K. 1976. A remnant in population Conf. Bear Res. and Manage. 4:243-247. and of its conservation. Int.Conf. Bear Norway problems ROGERS,L.L. 1987. Effects of food supply and kinship on Res. and 3:281-292. Manage. social behavior, movements, and population growth of ___ . 1987. The brownbear of cryptic population Norway. black bears in northeasternMinnesota. Wildl. Monogr. Int. Conf. Bear Res. and 7:13-16. Manage. No. 97. 72pp. D.M. 1981. and of black bears GRABER, Ecology management ROTH,H.U. 1976. Statusof the last brownbears of the Alps in in Yosemite National Park. Ph.D. Thesis, Univ. Calif., the Trentino, Italy. Int. Conf. Bear Res. and Manage. Berkeley. 206pp. 3:307-308. HARMS,D.R. 1979. National - 1976. 135-146 in parks Pages . 1980. Defecation rates of captive brown bears. Int. D. ed. The black bear in moder . Burk, Conf. Bear Res. and Manage. 4:247-253. Boone and Crocket Club. Amwell Press, Clinton, N.J. SINGER, F.J., AND S.P. BRATTON. 1980. Black bear/human 300pp. conflicts in the Great Smoky MountainsNational Park. _ . 1980. Black bear in Yosemite National management Int. Conf. Bear Res. and Manage. 4:137-139. Park. Int. Conf. Bear Res. and 4:205-212. Manage. SPRAGUE,A.E. 1925. more plentifulnow than 50 years B.K. ANDD.L. TURNER.1986. HASTINGS,B.C., GILBERT, ago in Estes Parkregion. Estes ParkTrail. 5 June 1925. Black bear in the of Yosemite aggression backcountry STEVENS,D.R. 1980. The deer and elk of Rocky Mountain NationalPark. Int. Conf. Bear Res. and 6:145- Manage. NationalPark. Natl. ParkServ. Mimeo. 163pp. 149. _ , and D.D. HANSON. 1986. The use of transplanting to S. 1985. Bear attacks. WinchesterPress, Piscata- HERRERO, expand bighorn sheep range. Proc. Bienn. North Am. N.J. way, 287pp. Wild Sheep Council. 5:166-177. ANDH.U. ROTH.1986. Home and move- HUBER,D., ranges WRIGHT, G.M., J.S. DIXON,AND B.H. THOMPSON.1932. Fauna bear in Plitvice Lakes National ments of brown Park, series No. 1. Natl. ParkServ., U.S. Dep. Inter. 157pp. Conf. Bear Res. and 6:93-97. Yugoslavia. Int. Manage. YOUNG,B.F., ANDR.L. RUFF.1982. Populationdynamics and KEAY, J.A., ANDJ.W. VANWAGTENDONK.1983. Effects of movementsof blackbears in east centralAlberta. J. Wildl. use levels on incidentswith black Yosemite backcountry Manage. 46(4):845-860. Conf. Bear Res. and 5:307-311. bears. Int. Manage. ZARDUS, M.J., ANDD.J. PARSONS.1980. Black bear manage- Bears and man in Glacier National MARSH,J.S. 1972. Park, ment in Sequoia and Kings Canyon National Parks. Int. British Columbia, 1880-1980. Int. Conf. Bear Res. and Conf. Bear Res. and Manage. 4:195-200. Manage. 2:289-296. MARTINKA,C. 1972. In Summaryof discussion. Int. Conf. Bear Res. and Manage. 2:334-336.