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Home , Florida black bear, Nyssa biflora

HABITATUSE BY AMERICANBLACK INTHE SANDHILLSOF

MARTY R. STRATMAN,1Department of Forestry, Wildlife, and Fisheries, University of Tennessee, 274 Ellington Hall, Knoxville, TN 37996, USA C. DAVIDALDEN, Department of Wildlife Ecology and Conservation, University of Florida, 303 Newins-Ziegler Hall, Gainesville, FL 32611, USA MICHAELR. PELTON, Department of Forestry, Wildlife, and Fisheries, University of Tennessee, 274 Ellington Hall, Knoxville, TN 37996, USA MELVINE. SUNQUIST, Department of Wildlife Ecology and Conservation, University of Florida, 303 Newins-Ziegler Hall, Gainesville,FL 32611, USA

Abstract: We used compositional analysis to determineseasonal and annualhabitat use by black bears ( americanusfloridanus) on Eglin Air Force Base (Eglin AFB), Florida, 1994-1996. Habitatuse was nonrandomfor annual (P = 0.0027), summer (P = 0.0002), and fall (P = 0.0006) periods. Riparianzones had the highest annualuse followed by swamps, pine plantations,sandhills, and open areas. Annual use of riparianzones and swamps differed (P = 0.025), and each showed greateruse than the remaininghabitat associations. Riparianzones and swamps also ranked highest for summerand fall. Sandhillsreceived their highest rank,third, in the fall. The high use of riparianzones demonstratesthe importanceof habitatsassociated with rivers and streamsto black bears on Eglin AFB.

Ursus 12:109-114

Key words: Americanblack ,compositional analysis, Eglin Air Force Base, habitat,radiotelemetry, riparian zones, sandhills, Ursus americanus floridanus

. . . I . . . ,.- - .1, - - I - - - " I ~I1111 I?------1 -- - " I11 1 % 11 . - -- A 1 I -- -- - L Black bears are listed as threatened by the state ot tion (4U- /u bears; rreedman zuuu) at Eglln Asi in nortn- Florida.They remainin just 8 relatively disjunctpopula- west Florida. Ourobjective was to determineannual and tions, largely due to land conversion for agricultureand seasonal habitatuse by black bears at Eglin AFB. urban development (Cox et al. 1994, Pelton and van Manen 1994; Fig. 1). Theirimperiled status coupled with recent increases in bear-vehicle collisions on Eglin AFB STUDYAREA promptedinterest in the dynamics of the bear population Eglin AFB (1,875 km2)is bounded by private land to thereand in identifyinghabitats important to bears on the the northand east and the Gulf of Mexico to the south and base. west. It is characterizedby rolling hills dissected by nu- Habitatuse has been evaluated for black bear popula- merous seepage streams. communities are diverse tions in (NF) (Wooding and and range from sandhills and pine production areas to Hardisky 1994), Osceola NF (Mykytkaand Pelton 1990, wetlandand riparian habitats (Table 1). The FloridaNatu- Wooding and Hardisky 1994), ApalachicolaNF (Seibert ral Areas Inventory(FNAI) documented35 naturalcom- 1993) in northand centralFlorida, and near Big Cypress munities on Eglin AFB (Provencheret al. 1996). National Preserve in south Florida (Land 1994). How- Seventy-two percent of Eglin AFB is comprised of ever, no informationis available from the small popula- sandhillsand pine productionareas. Many of these areas contain a dense oak (Quercus spp.) midstory and under- story of shrubs,vines, and saw palmetto. Dominant tree Okefenokee National include slash sand tur- Apalachicola g Wildlife Refuge, GA species longleaf pine, pine, pine, NationalForest laurel and sand live oak. Twelve of Osceola National key oak, oak, percent Forest the land has been cleared for airfields, test ranges, right- g E 1n l rOcalaNational and administrativeareas. Test are main- AirForce Base Forest of-ways, ranges tained in an condition. The areas Johns open grass remaining Chassahowitzka Natio St National Wildlife Refuge Wildlife Refuge are comprised of wetland and riparianhabitats. Domi- nant tree species in those habitatsinclude titi, slash pine, redbay,magnolias, and bald cypress. 150 300 Kilometers

Legend Occtupied range METHODS _ Publlic lands with resident populations Big Cypress National Preserv Trappingand Handling We trappedblack bears with spring-activatedfoot snares Fig. 1. Distribution of black bears in Florida and vicinity, andimmobilized them with a mixtureof Ketaset 1994-96. (8.8 lmg/

'Presentaddress: Stillwater-Ohio Creek, 430 Tincup Dr., Gunnison,CO 81230, USA, email: [email protected] 110 Ursus 12:2001

Table1. Primaryoverstory and understoryplant species of knownlocations that could be identifiedaccurately on U.S. 5 habitatassociations on Eglin Air Force Base, Florida, We each 1994-1996. Geological Survey topographicmaps. plotted stationand assigned an identificationnumber; Universal Habitattype Plant species TransverseMercator coordinates were recorded to the Sandhills Longleaf pine (Pinus palustris) nearest 10 m. oak Turkey (Quercus laevis) We obtained >2 azimuths to estimate bear locations. Laureloak (Q. hemisphaerica) Sand live oak (Q. geminata) We selected azimuthsbased on the following criteria:(1) Blueberry( spp.) the angle between all azimuthshad to be 60-120? and (2) Saw palmetto ( repens) the time intervalbetween all azimuthshad to be <20 min- Greenbriar(Smilax spp.) utes. Individualbears were located 2-5 times/week. For Pine production Slash pine (P. elliottii) all locations,we recordedthe observer,azimuth, and time areas of for each Sand pine (P. clausa) day bearing. Sand live oak We also obtainedhourly locations on selectedindividu- Blueberry als during24-hour tracking periods conducted 1-2 times Saw palmetto the summer,late summer,and fall seasons Greenbriar during early (Stratman1998). We used the softwareprogram TELEM Wetlands Slash pine 88 (Colemanand Jones 1988) to generateanimal location Titi ( racemiflora) coordinatesfrom the azimuthand telemetrystation data. Black titi (Cliftoniamonophylla) We collectedradiolocations from November 1994 Redbay (Persea borbonia) through Bald cypress (Taxodiumdistichum) October 1996. Blackgum () Sweet gallberry(Ilex coriacea) HabitatUse Bitter gallberry(I. glabra) Analysis Fetterbush() We obtainedhabitat data including coverage maps for streams,rivers, wetlands, roads, and habitat types in a digi- Riparianzones Southernmagnolia (Magnolia grandiflora) tal databasefrom the NaturalResources Division, Jack- Sweetbay magnolia (M. virginiana) Slash pine son Guard,Eglin AFB. They determinedhabitat types Titi from aerial photographsand field surveys conductedby Laureloak FNAI and habitatfeatures from 1:24,000 maps Floridaanise digitized (Illiciumfloridanum) a cell of 10 m x 10-m We Bitter gallberry using grid density (10- cells). Saw palmetto convertedthe databaseinto Arc/Infoformat (Environmen- Greenbriar tal Systems Research, Inc., Redlands, California,USA) for and reclassification. Because the habi- Open areas Turkeyoak manipulation Runneroak (Q. pumila) tat coverage map contained over 20 habitat types, we Bluestem (Andropogonspp.) groupedhabitats based on floral, faunal,and geophysical Broomsedge (A. virginicus) similarities(McWhite et al. 1993) for analysis (Table2). Woolly panicum (Panicum spp.) We defined 5 habitatassociations: sandhills, pine pro- kg; ketamine hydrochloride,Bristol Laboratories,Syra- duction areas, riparianzones, swamps, and open areas. cuse, New York, USA), Rompun (4.41mg/kg; xylazine Pine productionareas are managedstrictly for timberand hydrochloride,Haver-Lockhart, Inc., Shawnee, Kansas., pulpwoodproduction (McWhite et al. 1993),thus we sepa- USA), and Carbocaine(0.88 mg/kg; mepivicainehydro- ratedthem from sandhillsto determinetheir use by bears. chloride, WinthropLaboratories, New York, New York, Riparianzones were areas<50 m from a river and <25 m USA). The drug was administeredwith a jab stick or from a stream;these distanceswere generallywhere veg- carbondioxide-powered dart pistol at a dosage of 1 ml/ etational composition between riparianzones and other 22.7 kg of estimatedbody weight. We fitted all captured habitat associations differed. Open areas consisted of bears with radio collars (Telonics, Inc., Mesa, Arizona, clearedairfields, test ranges,right-of-ways, clearcuts, and USA). sewage spray fields. Home range perimeters,estimated with the 95% adaptivekernel method (Worton 1989), and Radiotelemetry locations of radiocollaredbears were formattedand up- We determinedthe locations of radiotaggedbears us- loaded into Arc/Info. ing triangulationtechniques with 5-element, vehicular We used compositionalanalysis to determineseasonal roof-mounted antennas (Wildlife Materials, Inc., and annual habitatuse by black bears (Aebischer et al. Carbondale,Illinois, USA) usingthe loudestsignal method 1993). Sample size was the numberof trackedanimals, (Mech 1983). Telemetry stations were established at not the numberof radiolocations.We regardedserial cor- BLACKBEAR HABITATUSE * Stratmanet al. 111

Table 2. Plant communitiesand land uses for 5 habitat habitatassociations in orderof increasingrelative use. associationson EglinAir Force Base, Florida,1994-1996.

Habitatassociation Hectares (%) Plant communityor land TriangulationError Analysis To determinethe effects of erroron estimates Sandhills 90,196 (51%) Sandhill telemetry Sandpine-oak forest of habitatuse, we placed test collars in areaswhere bears Scrub were typically located to simulate actual bear locations Upland mixed forest and signal strength. All observerslocated test collars us- Upland pine forest ing procedurespreviously described. We thendetermined Pine productionareas 38,490 (21%) Pine production the distance from the estimatedlocation to the true loca- tion for each observer to estimate an error distribution Open areas 23,400 (12%) Air fields Developed areas (Schmutzand White 1990). Power line right-of-way Because the numberof locations and mean errorwas Roads differentbetween we errordistances Sewage disposal areas observers, weighted Test ranges by the percent of locations collected by each observer. The errordistances for the observerswith the most loca- Swamps 20,314 (12%) Baygall Depression marsh tions were weightedproportionately more than those with Dome swamp the fewest numberof locations. We then calculatedthe forest Floodplain numberof randomlocations needed to approximatethe Hydric hammock Mesic flatwoods errordistribution and generateda set of simulatederror Sandhillupland lake locations at uniformrandom azimuths from the original Scrubbyflatwoods coordinatesbased on the distri- Wet flatwoods radiotelemetry weighted butionof distancestest collars were from lo- Wet prairie triangulated cations (Stratman 1998). We recorded habitat Riparianzones 15,082 (4%) Seepage slope characteristicsfor each set of simulatedlocations for com- forest Slope with Uplandhardwood forest parison the habitatcharacteristics of the originalte- Xeric hammock lemetry locations. We used compositional analysis to determine the ef- relationbetween radiolocationsas irrelevantbecause lo- fects of telemetryerror on habitatuse by testing each set cations were collected consistently throughoutthe sam- of simulatederror locations againstthe originaldata. If a pling period and sampling intensity was uniform differencewas detected(P < 0.05), we concludedthat te- (Aebischeret al. 1993). Thus, we includedthe diel loca- lemetryerror significantly affected habitat use estimates. tions in the analysis, which provideda more precise esti- mate of proportionalhabitat use. For each bear,we weighted habitatcomposition by the RESULTS squareroot of the numberof locations, because the num- We collected 1,891 locationestimates from 9 bears(3F, ber of radiolocations was not consistent for all bears 6M) to determine annual habitat use. Seasonal habitat (Aebischer et al. 1993). Aebischer et al. (1993) noted use was based on 10 bears (3F, 7M) located duringsum- thata 0% use value implies thatuse was so low thatit was mer (1,049 locations) and fall (794 locations). We ob- not detected,and this meaningshould be preservedin the tained 77 locations on test collars. The mean errorand analysis. Therefore,all 0% use values were replacedwith numberof locations for each observer(A-F) were A: x= 0.001%, which was less than any existing value in either 71 m, 1,402 locations;B: x= 219 m, 301 locations;C: x= availableor utilizedcompositions (Aebischer et al. 1993). 216 m, 92 locations; D: x = 191 m, 30 locations; E: x= Because a minimumsample size of 6 was requiredto show 218 m, 32 locations; and F: x = 278 m, 34 locations. a significantdifference from zero at P < 0.05 (Aebischer Ninety percent of the estimated locations were <390 m et al. 1993), we consideredthe sample sizes for sex and from the test location, and 50% were <155 m. The per- age classes insufficientfor analysis. We tested the effects cent of locationsfor annual,summer, and fall seasons that of individual habitat selection and found no significant were classifieddifferently using the simulateddata set was = individual effects (P 0.242); therefore,the data were 10%,7.7%, and 8.5%, respectively. pooled. Annualhabitat use by black bearswas not random(A = We defined summer as 1 June-30 Septemberand fall 0.0576, F = 20.46, P = 0.0027). Riparianzones ranked as 1 October-31 January(Stratman 1998). Spring was highestamong the 5 habitatassociations on an annualbasis not included as a season because of low sample sizes. (Table3). Use differed(P = 0.025) betweenriparian zones When we detectednonrandom use (P < 0.05), we ranked and swamps, and each showed greateruse than the re- 112 Ursus 12:2001 maininghabitat associations. Althoughsandhills was the sion. In fragmentedhabitat in Louisiana,bears used drain- most availablehabitat to bears,it rankedfourth in annual age ditches as narrowas 10 m for movementthrough ag- use. riculturalareas and dennedin drainagesonly 140 m wide Habitatuse also was nonrandomduring summer(A = (Weaveret al. 1992, Anderson 1997). However,riparian 0.038, F= 37.95, P = 0.0002) and fall (A = 0.0541, F = zones were not the most frequentlyused habitatavailable 26.20, P = 0.0006). For both seasons, riparianzones to bears in that area. rankedhighest followed by swamps (Table3). Therewas In this study, bears used riparianzones because they a difference in use between riparianzones and swamps providedan annualsource of food as well. In some situ- duringsummer (P = 0.001), but no differencefor fall (P ations, high edge-to-arearatio can be detrimentalto bear = 0.132). Open areas were used less (P < 0.05) than all populationsbecause of the potential increase in human- otherhabitat associations, both annuallyand seasonally. induced mortality(Hellgren and Vaughan1994). How- There was no overall effect of telemetry erroron an- ever, the high edge-to-arearatio on Eglin AFB, coupled nual (P = 0.7342), summer (P = 0.2611), or fall (P = withthe plantspecies compositionand moist environment, 0.4064) habitatuse estimates. Telemetryerror had a lim- providedabundant food resourcesduring most of the year. ited effect on the rankingof habitats.The rankingof habi- Becausebear movements and home rangesizes arelargely tat associations for annual and fall habitat use did not affected by the distribution and abundance of foods change. For summer,the rankingof pine productionar- (Garshelis and Pelton 1981, Rogers 1987, Smith and eas and sandhillswas reversed. Pelton 1990), maintainingplant species diversity, espe- cially primarybear foods, within and adjacentto riparian zones could effectively minimize the area needed to sat- DISCUSSION isfy the nutritionalneeds of black bears on Eglin AFB. The high proportionof locations collected by the ob- Bears used swamps throughoutthe year, but mostly in serverwith the smallest mean errorwas a primaryfactor late fall and winter. However,many of the swamps used in reducingthe effects of telemetryerror on habitatuse. by bears on Eglin AFB were narrowbands within ripar- The relatively high proportionof misclassified locations ian zones;some were <5 ha in size. Thesebands of swamp was attributedto the large numberof bear locations near likely enhancedthe attractivenessof the riparianzones to habitatedges. Misclassifiedlocations did not significantly bears because of their dense vegetationand inaccessibil- would in- changeuse values becausemany of themwere transposed ity. An increase in the bear populationlikely between habitattypes, thus, canceling each other out. crease the importanceof these small patches of swamp Black bears on Eglin AFB demonstrateddistinct habi- for long-termsurvival of black bears on Eglin AFB. used morethan tatpreferences. Riparianzones and swampsranked high- Pine productionareas were significantly est amongthe habitatsavailable to bears. In contrast,bears sandhillsduring the summerseason. Althoughpine pro- and sand in Osceola NF preferredlarge swamps (Mykytka and duction areas consisted primarilyof slash pine in Pelton 1990); in Ocala NF, they favored flatwoods and pine plantations,the majorityof use by bearsoccurred areaswere closed for- sand pine scrub habitats(Wooding and Hardisky 1994); slash pine. Most sandpine canopy not and in southwest Florida, they preferredpine-palmetto ests with little or no understory;bears probably were of the lack of food in these habitats and agricultural-disturbedareas (Land 1994). attractedto sandpine because notedthat This diversityof habitatuse by blackbears in Floridadem- areas. However,Wooding and Hardisky (1994) Ocala corre- onstratesthe adaptabilityof bears to differencesin land- the use of sand pine scrub on NF, Florida, the of hardmast there. scapes and habitatavailability. spondedto availability ranked fall than other Riparianzones represent<5% of the land areaon Eglin Sandhills higher during during due to the mast failure of AFB. The high use of riparianzones by black bears re- seasons. This was primarily when bears switched to acorns as flects the uniquenessof this habitatfeature and its impor- saw palmettoin 1995, Be- tance to black bears on the area. This is the first time the primaryfall food (Stratmanand Pelton 1999). oak mast is an fall food for bears, san- riparianzones have been reportedto be the primaryhabi- cause important habitatsnear zones and thatcontain tat type used by black bears in the Southeast. dhill riparian swamps can minimizetravel to cover. The networkof riparianzones allowed bears to travel a matureoak midstory escape over largeareas while remainingnear escape cover. Also, most of the dense vegetation adjacentto streamsranged from 10-100 m wide. The closed canopy and dense un- MANAGEMENTIMPLICATIONS use of zones demonstratesthe derstory of fetterbush, gallberry, saw palmetto, and The high riparian impor- of habitatsassociated with rivers and streams to black greenbriar(Smilax spp.) likely enhancedtheir attractive- tance The networkand dendritic ness to bearsby providingfood, escape cover, and seclu- bears on Eglin AFB. unique BLACKBEAR HABITAT USE * Stratmanet al. 113

Table 3. Rankingmatrices for annual and seasonal habitat use by black bears on Eglin Air Force Base, Florida,1994-96. Each mean element in the matrixwas replaced by its sign; a triple sign represents significant deviation from random at P < 0.05.

Season

------Habitattype Habitattype-,F r- Riparian Swamp Pine Sandhills Open Rank Annual 1 Riparian Swamp 2 Pine + 3 Sandhills 4 Open 5 Summer Riparian Swamp Pine Sandhills Open Rank Riparian 1 Swamp 2 Pine 3 Sandhills 4 Open 5 Fall Riparian Swamp Sandhills Pine Open Rank Riparian + 1 Swamp +++ 2 Sandhills + 3 Pine 4 Open 5 patternof riparianareas effectively links habitatsthrough- theirassistance throughout the project. We thankET. van out Eglin AFB and vicinity. This networkof naturalpro- Manen, D. Martorello,J.D. Clark, and 2 anonymousre- tected corridorsenables black bears to move to various viewersfor providing helpful comments on the manuscript. seasonalfeeding areasas well as providingfood, thermal relief in and habitat. summer,escape cover, denning Be- LITERATURECITED cause bearsuse a varietyof foods thatare only seasonally AEBISCHER,N.J., P.A. ROBERTSON,AND R.E. KENWARD.1993. available,habitat diversity is importantto satisfy theirdi- Compositional analysis of habitat use from radio- etaryneeds. In addition,management of uplandhabitats trackingdata. Ecology 74:1313-1325. adjacentto riparianzones and swamps for soft and hard ANDERSON, D.R. 1997. Corridoruse, feeding ecology, and mast would areas for bears production provide foraging habitatrelationships of blackbears in a fragmentedlandscape while minimizing travel to escape cover. in Louisiana. Thesis, University of Tennessee, Knoxville, Humandemands on the landscapewill inevitablycause Tennessee, USA. bearpopulations to become morefragmented and isolated. COLEMAN,J.S., ANDA.B. JONESIII. 1988. User's guide to Propermanagement of riparianzones on Eglin AFB could TELEM88: Computeranalysis system for radio-telemetry data. Research Series 1. providea valuabletool to link otherisolated bearpopula- Department of Fisheries and Wildlife, Instituteand State tions in Florida. The futureof this small isolated popula- VirginiaPolytechnic University, Blacksburg,Virginia, USA. tion is in jeopardy unless management strategies are Cox, J., R. KAUTZ,M. MACLAUGHLIN,AND T. GILBERT.1994. implementedto preserveand enhancecritical habitats for Closing the gaps in Florida's wildlife habitatconservation bears. Because of theirlimited availability,management system. Office of EnvironmentalServices, Florida Game of zones is a element to riparian key the survivalof black and Fresh Water Fish Commission, Tallahassee, Florida, bearson Eglin AFB. The integrityof riparianzones must USA. be preservedif this populationis to persist. FREEDMAN,A.H. 2000. Black bearpopulation ecology on Eglin Air Force Base, Florida and life-stage simulation models for blackbear conservation on the southeasterncoastal plain. ACKNOWLEDGMENTS Thesis, University of Florida,Gainesville, Florida,USA. GARSHELIS,D.L., ANDM.R. PELTON.1981. Movementsof black The Departmentof Defense, Legacy Resource Man- bearsin the GreatSmoky MountainsNational Park. Journal agementProgram and U.S. Air Force, AFB, Florida Eglin of Wildlife Management45:912-925. provided for this thanks to funding project. Special go HELLGREN,E.C., ANDM.R. VAUGHAN.1994. Conservation and C.J. Petrick, B. D. and D. Hagedorn, Teague, Smith for management of isolated black bear populations in the 114 Ursus 12:2001

southeastern coastal plain of the United States. Annual in northwesternMinnesota. Wildlife Monograph97. Conferenceof SoutheasternAssociation of Fish andWildlife SCHMUTZ,J.A., ANDG.C. WHITE.1990. Error in telemetry Agencies 48:276-285. studies:effects of animalmovement on triangulation.Journal LAND,E.D. 1994. Southwest habitatuse, of Wildlife Management54:506-510. distribution,movements, and conservationstrategy. Final SEIBERT,S.G. 1993. Status and managementof black bears in Report W-41-32. Florida Game and Fresh Water Fish Apalachicola National Forest. Final Report W-41-30. Commission,Tallahassee, Florida, USA. Florida Game and Fresh Water Fish Commission, McWHITE,R.W., D.R. GREEN,C.J. PETRICK,AND S.M. SEIBER. Tallahassee,Florida, USA. 1993. Naturalresources management plan, Eglin Air Force SMITH, T.R., AND M.R. PELTON. 1990. Home ranges and Base, Florida 1993-1997. U.S. Air Force, Eglin Air Force movementsof black bearsin a bottomlandhardwood forest Base, Florida,USA. in Arkansas. InternationalConference on Bear Research MEcH,L.D. 1983. Handbookof radio-tracking.University of and Management8:213-218. MinnesotaPress, Minneapolis,Minnesota, USA. STRATMAN,M.R. 1998. Habitatuse and effects of prescribed MYKYTKA,J.M., AND M.R. PELTON.1990. Managementstrategies fire on black bears in northwestern Florida. Thesis, for Florida black bears based on home range habitat University of Tennessee, Knoxville, Tennessee,USA. composition. InternationalConference on Bear Research , and M. Pelton. 1999. Feeding ecology of black bears and Management8:161-167. in northwestFlorida. FloridaField Naturalist27:95-102. PELTON,M.R., ANDF.T. VAN MANEN. 1994. Distributionof black WEAVER,K.M., D.K. TABBERER,L.U. MOOREJR., G.A. CHANDLER, bears in North America. EasternWorkshop on Black Bear J.C. POSEY,AND M.R. PELTON.1992. Bottomland hardwood Researchand Management12:133-138. forest managementfor black bears in Louisiana. Annual PROVENCHER,L., D.R. GORDON,K.E.M. GALLEY,J.L. HARDESTY, Conferenceof SoutheasternAssociation of Fish andWildlife H.L. RODGERS,J. SHEEHAN, E. LEVINE,G.W. TANNER,L.A. Agencies 44:342-350. BRENNAN,AND K.W. BLANDFORD.1996. Pre-restoration WOODING,J.B., ANDT.S. HARDISKY.1994. Home range, habitat analysis of , invertebrates, and birds in sandhills use, and mortality of black bears in north-centralFlorida. systems at Eglin Air Force Base, Florida:Annual reportto InternationalConference on BearResearch and Management naturalresources division, Eglin Air ForceBase. The Nature 9(1):349-356. Conservancy,Niceville, Florida,USA. WORTON,B.J. 1989. Kernel methods for estimating the ROGERS,L.L. 1987. Effects of food supplyand kinship on social utilization distribution in home range studies. Ecology behavior,movements, and population growth of black bears 70:164-168.