home ranges of sympatric mule deer and white-tailed deer in texas

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Home Ranges of Sympatric Mule Deer and White-Tailed Deerin TexasAuthor(s): Kristina J. Brunjes, Warren B. Ballard, Mary H. Humphrey,Fieldling Harwell, Nancy E. McIntyre, Paul R. Krausman, and Mark C.WallaceSource: The Southwestern Naturalist, 54(3):253-260. 2009.Published By: Southwestern Association of NaturalistsDOI: http://dx.doi.org/10.1894/MD-06.1URL: http://www.bioone.org/doi/full/10.1894/MD-06.1

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HOME RANGES OF SYMPATRIC MULE DEER ANDWHITE-TAILED DEER IN TEXAS

KRISTINA J. BRUNJES, WARREN B. BALLARD,* MARY H. HUMPHREY, FIELDLING HARWELL,

NANCY E. MCINTYRE, PAUL R. KRAUSMAN, AND MARK C. WALLACE

Department of Natural Resources Management, P.O. Box 42125, Texas Tech University,

Lubbock, TX 79409 (KJB, WBB, MCW)

Texas Parks and Wildlife Department, Sonora, TX 76950 (MHH)

Texas Parks and Wildlife Department, Kerrville, TX 78028 (FH)

Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409 (NEM)

School of Natural Resources, University of Arizona, Tucson, AZ 85721 (PRK)

*Correspondent: [email protected]

ABSTRACT—Sympatry can create special dynamics between populations and impact managementstrategies for each species. We estimated size and overlap of home ranges and core areas of sympatricfemale mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) in west-central Texas. Wecaptured 50 mule deer and 53 white-tailed deer, fitted them with radiocollars, and monitored themduring 2000–2002. Average (6SE) size of home range of mule deer in spring was 3.9 6 0.32 km2, whilethat of white-tailed deer was 4.32 6 0.77 km2; sizes of home ranges in summer were 2.82 6 0.32 and 2.086 0.23 km2, respectively. Interspecific overlap of home range between seasons was similar tointraspecific overlap. Overlap in core area also was similar within and between species during summer,but interspecific overlap in core area was less during spring.

RESUMEN—La simpatrıa entre especies puede crear dinamicas particulares en sus poblaciones y afectarla efectividad de estrategias de manejo. Estimamos el tamano y el traslape de los rangos de hogar y de lasareas nucleares entre hembras del venado bura (Odocoileus hemionus) y venado cola blanca (O.virginianus) en el centro-oeste de Texas. Capturamos 50 venados bura y 53 venados cola blanca, lescolocamos radio-collares y los monitoreamos del 2000–2003. El promedio del rango de hogar (6ES)durante la primavera fue de 3.9 6 0.32 km2 en el venado bura mientras que el del venado cola blancafue de 4.32 6 0.77 km2; durante el verano fue de 2.82 6 0.32 y 2.08 6 0.23 km2, respectivamente. Eltraslape interespecıfico del rango de hogar entre estaciones fue similar al traslape intraespecıfico. Eltraslape de areas nucleares fue tambien similar entre individuos de la misma especie que entre las dosespecies durante el verano, pero el traslape interespecıfico fue menos en la primavera.

In Texas, geographic distributions of muledeer (Odocoileus hemionus) and white-tailed deer(O. virginianus) overlap in portions of the Trans-Pecos region, the western edge of the EdwardsPlateau, and in the Texas Panhandle (Smith,1987). White-tailed deer have become moreabundant in areas previously considered to beoccupied only by mule deer (W. F. Harwell andH. G. Gore, in litt.), and mule deer havedecreased or disappeared entirely from someareas (Wiggers and Beasom, 1986). Amount ofarea used by female deer and their survival are ofinterest to private landowners and managers ashunting is a significant economic contribution inTexas (S. Lightwood, unpublished data). Income

from hunting leases or other wildlife recreationcan supplement or even exceed that fromtraditional domestic livestock (Butler and Work-man, 1993). Managers may wish to implementmanagement activities to benefit primarily white-tailed deer because of higher bag limits andlonger hunting seasons. However, others mayprefer to manage habitat to favor mule deer.

Our objectives were to investigate differencesin size of home range and degree of overlap ofhome ranges and core areas between the twospecies. Because allopatric female white-taileddeer in semi-arid and arid regions tend to havesmaller home ranges (Gallina et al., 1997) thanallopatric female mule deer in similar environ-

THE SOUTHWESTERN NATURALIST 54(3):253–260 SEPTEMBER 2009

ments (Dickinson and Garner, 1979; Hayes andKrausman, 1993; Relyea et al., 2000), we predict-ed that mule deer would have larger homeranges than white-tailed deer in west-centralTexas. However, because these species are notterritorial and have similar diets (Anthony, 1972;Krausman, 1978), we predicted that there wouldbe overlap in home ranges. Other studies ofsympatric deer have determined that the speciesmaintain separate distributions, but these studiesoccurred in prairies of Montana (Wood et al.,1989) and grasslands of Colorado (Whittaker,1995), where deer are subject to harsh winterconditions and are partially migratory.

MATERIALS AND METHODS—The study was conductedon five contiguous ranches (ca. 323 km2 in total area)in the northwestern corner of Crockett County, Texas,on the western edge of the Edwards Plateau. Lowerelevations were dominated by mesquite (Prosopis),creosotebush (Larrea tridentata), tarbush (Flourensiscernua) and prickly pear (Opuntia). Juniper (Juniperus)was the dominant woody species on mesas. Washessupported dense thickets of hackberry trees (Celtisoccidentalis). Slopes supported xeriphytic plants such asyuccas (Yucca) and ocotillo (Fouquieria splendens;Correll and Johnston, 1970). Livestock grazing, oilproduction, and hunting were ongoing on all ranches(Brunjes, 2004).

Topography consisted of broad, level plateaus,rolling hills, and steep canyons. Elevation was 700–915 m. Mean annual precipitation for 2000–2002 was25 cm (average for 1963–1997 was 43 cm). Mostrainfall occurred May–September; greatest amountsusually occurred during September. Average annuallow temperature was 10uC and average annual high was26uC. In winter, daily temperatures ranged from aminimum of 21uC to a maximum of 16uC, and insummer, 16–32uC (National Oceanic and AtmosphericAdministration, 2000, 2001, 2002; http://www.ncdc.noaa.gov).

We estimated densities of deer with the aid of ahelicopter during February 2001. The pilot and oneobserver surveyed the study area by flying adjacent belttransects ca. 200 m wide at an altitude of ca. 30 m. AGarmin Geographic Positioning System unit (GarminLtd., Olathe, Kansas) was used to plot transects andmaintain parallel flight lines. Surveys began at 0800 hand ended at 1700 h; the entire study area was surveyedin 5 days. We counted deer on both sides of thehelicopter and used composition of group, character-istics of antlers, and location to determine if deer hadbeen counted previously (DeYoung, 1985). We classi-fied deer to species, sex, and age (juvenile or adult).We calculated number of deer per unit area and ratioof males to females and juveniles to adult females forthe study area.

On 2–3 February 2000 and 30 January 2001,personnel from Holt Helicopters (Uvalde, Texas)randomly captured deer with a net-gun fired from ahelicopter following the protocol outlined by Kraus-

man et al. (1985). We recorded sex and condition ofeach animal and estimated age of deer by toothwearand replacement (Severinghaus, 1949; Robinette et al.,1957). We fitted each deer (both sexes) with anumbered plastic eartag and a 500-g radiocollarequipped with a motion-sensitive mortality switch(Telonics, Mesa, Arizona).

We conducted radiotracking with a truck-mounted,null-peak system consisting of two 4-element Yagiantennas mounted on a rotating, telescoping, boomin the truck-bed. We located deer using methods ofWhite and Garrott (1990) that recommended #20 minbetween first and last azimuth. One to two observersparticipated. We used the program LOAS (EcologicalSoftware Solutions, Sacramento, California) to deter-mine locations of deer. We located collared females .4times/month during January–August 2000–2002 toestimate size of home ranges. Deer were not locatedduring hunting season (September-mid-January) incompliance with requests of landowners. We rotatedtiming of relocations sequentially through 3 timeblocks (0500–1059, 1100–1659, 1700–2400 h). Wedetermined telemetry error following recommenda-tions of White and Garrot (1990) by using collars inknown locations and then located by individuals thatdid not know where the transmitter was located. Weused the Animal Movement extension for ArcView(Hooge and Eichenlaub, 2000) to calculate size ofhome ranges using the 95% and 50% fixed-kernel andminimum-convex-polygon methods. We calculated sizeof home range using the minimum-convex-polygonmethod for 13–17 mule deer and 14–19 white-taileddeer/season and year for comparison to previouslypublished studies based upon a minimum of 30locations/season, but used only size of home rangesgenerated with 95% and 50% fixed-kernel methods forfurther analysis. We used size of home rangesdetermined using the 50% fixed-kernel method as anapproximation of the core area of each animal(Loveridge and Macdonald, 2003). Home ranges werecalculated for winter–spring, which encompassed thepregnancy period (January–April) and summer, thefawning season (May–August). Size of home ranges andcore areas were calculated for each season and year forindividuals having .30 locations in that season.

We used ArcView software to identify the polygoncreated when core areas or home ranges overlapped.Each overlapping polygon was assigned as muledeer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer. If $1 location of eitheranimal occurred within that overlapping polygon, wecalculated an overlap index using the following ratio:

n1zn2ð Þ= N1zN2ð Þ½ �|100

where n1 and n2 refer to respective number of locationsfor each deer within the overlapping polygon, and N1

and N2 refer to the respective total number of locationsrecorded for each deer used to calculate size of homerange (Chamberlain and Leopold, 2002). We used thisprocedure to calculate indices of overlap for core areas.We also calculated indices of overlap of home ranges ofindividual deer for spring and summer to quantifyseasonal differences. We did not calculate interspecificindices of overlap for 2000 because only three instances

254 The Southwestern Naturalist vol. 54, no. 3

of interspecific overlap in home range were detected.This is likely due to the fact that in 2000 we endeavoredto spread our capture effort throughout the entirestudy area. During 2001, we concentrated our efforts inthe center of the study area, resulting in increaseddetection of overlapping core areas and home rangesamong collared animals.

We used Levene’s test to check for homogeneity ofvariance for all comparisons and examined residualsfor normality (Zar, 1999; Bryce et al., 2002). If Levene’stest was insignificant and data were distributednormally, we used analysis of variance (a 5 0.05) tocompare mean size of home ranges between years andages within species and between species, and to test forinteractions (White and Garrott, 1990). When Levene’stest was significant, indicating inequality of variances,we used Kruskal-Wallis for one-way comparisons, andFriedman’s test for two-way comparisons (Zar, 1999).Because of unequal samples, Fisher’s LSD test was usedfor separation of means in comparisons of overlap.

RESULTS—Estimated densities of deer duringthe helicopter survey in February 2001 were 2.4mule deer/km2 and 1.6 white-tailed deer/km2.Number of adult females per adult male in 1999,prior to initiation of the study, was 1:3 for muledeer and 1:7 for white-tailed deer; the ratio in2001 was 1:3 for both species. Number of fawnsper adult female in 1999 was 0.5:1 for mule deerand 0.4:1 for white-tailed deer; in 2001, the ratiowas 0.2:1 for both species.

We captured and fitted 40 females of eachspecies with radiocollars in January 2000. InJanuary 2001, we captured and collared anadditional 13 white-tailed deer and 10 muledeer. Mean age at capture was 4.5 years for bothspecies (range for mule deer 5 2.5–6.5; range forwhite-tailed deer 5 1.5–7.5). Average bearingerror was 67u based on triangulated locations ofcollars in known locations. Mean size of homeranges determined by the minimum-convex-poly-gon method were similar between species inboth seasons (Table 1).

Mean size of core areas determined by the50% fixed-kernel method did not differ amongseasons across years for either species (muledeer: F5 5 1.28, P 5 0.28; white-tailed deer: F5 5

1.05, P 5 0.39). Size of core areas betweenseasons was averaged across years within speciesto compare spring and summer (Table 1). Meansize of core areas in spring determined by the50% fixed-kernel method was greater than size ofcore areas in summer for white-tailed deer (F1 5

5.18, P 5 0.03), but not for mule deer (F1 5 0.79,P 5 0.38). Mean size of core areas determined bythe 50% fixed-kernel method was not different

between mule deer and white-tailed deer forspring (F1 5 0.08, P 5 0.78) or summer (F1 5

3.59, P 5 0.06).Mean size of home range determined by the

95% fixed-kernel method did not differ amongseasons across years for either species (muledeer: F5 5 0.70, P 5 0.62; white-tailed deer: F5 5

1.74, P 5 0.13; Table 1). Mean size of homerange determined by the 95% fixed-kernelmethod for spring was greater than that insummer for white-tailed deer (F1 5 8.50, P ,

0.01), but not for mule deer (F1 5 1.56, P 5

0.21). Within seasons, mean size of home rangedetermined by the 95% fixed-kernel method wasnot different between mule deer and white-taileddeer for spring (F1 5 1.25, P 5 0.27) or summer(F1 5 3.57, P 5 0.06).

Within species, core areas in summer partiallyoverlapped core areas in spring for individualdeer during all years (Table 2). Indices ofoverlap were not different among years (F1 5

1.01, P 5 0.37) or between species (F2 5 0.01, P5 0.92), nor was there a species-by-year inter-action (F2 5 0.97, P 5 0.38). Both speciesexhibited greater individual fidelity in homerange determined by the 95% fixed-kernelmethod within each year. However, as with coreareas, indices of overlap were not differentamong years (F1 5 0.85, P 5 0.43) or betweenspecies (F2 5 0.18, P 5 0.67), nor was there aspecies-by-year interaction (F2 5 0.91, P 5

0.41).Core areas and home ranges of individual

animals for spring and summer also overlappedacross years within seasons (Table 3). The indexof overlap for core areas from spring to springwas greater for mule deer than for white-taileddeer (F1 5 4.29, P 5 0.04). Overlap in core areasfrom summer to summer also was greater formule deer (F1 5 9.60, P , 0.01). However,overlap of home ranges in spring and summerwere not different across years (F1 5 2.57, P 5

0.12 and F1 5 3.25, P 5 0.08, respectively).We observed instances of interspecific and

intraspecific overlap of home ranges and coreareas; however, differences among mule deer:mule deer, mule deer:white-tailed deer, orwhite-tailed deer:white-tailed deer occurredonly in core areas (Table 4). In spring 2002,intraspecific overlap was greater than interspe-cific overlap for both species (x2

2 5 10.35, P ,

0.01). With the exception of summer 2001,interspecific overlap tended to be lower than

September 2009 Brunjes et al.—Home ranges of sympatric deer 255

TABLE 1—Size of seasonal home ranges (km2) determined using the minimum-convex-polygon (MCP), and 95%fixed-kernel methods, and size of seasonal core areas (km2) determined using the 50% and 95% fixed-kernelmethod for female mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) in west-central Texasduring spring and summer, 2000–2002.

Size of home range (MCP) Year Season n Mean SE

Mule deer 2000 Spring 13 1.68 0.17Summer 14 1.88 0.20

2001 Spring 15 1.26 0.21Summer 15 1.28 0.21

2002 Spring 17 1.76 0.24Summer 15 1.30 0.16

Mean seasonal Spring 17 1.28 0.14Summer 15 1.16 0.11

Annual 15 2.30 0.19

White-tailed deer 2000 Spring 14 1.46 0.11Summer 19 1.53 0.08

2001 Spring 15 1.45 0.20Summer 14 1.20 0.25

2002 Spring 16 2.37 0.30Summer 17 1.12 0.21


Annual 16 2.25 0.21

Size of core areas (50% kernel)


2001 Spring 15 0.80 0.17Summer 15 0.58 0.23

2002 Spring 17 0.55 0.11Summer 15 0.42 0.03


Annual 15 0.51 0.08


2001 Spring 15 0.77 0.16Summer 14 0.44 0.07

2002 Spring 16 0.72 0.10Summer 17 0.41 0.09

Mean seasonal Spring 16 0.78a 0.16Summer 19 0.42b 0.05

Annual 16 0.42 0.06

Size of home range (95% kernel)


2001 Spring 15 3.29 0.60Summer 15 2.87 0.39

2002 Spring 17 3.38 0.48Summer 15 2.26 0.23


Annual 15 2.47 0.29


intraspecific overlap during both seasons. De-gree of interspecific overlap did not differamong seasons or years for either species (F2

5 0.48, P 5 0.69), but they were differentamong mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-taileddeer (F2 5 3.03, P 5 0.04); there was no seasonand year interaction for mule deer:mule deer,mule deer:white-tailed deer, or white-taileddeer:white-tailed deer (F6 5 1.67, P 5 0.13).Overlap in home range determined by the 95%fixed-kernel method was similar among muledeer:mule deer, mule deer:white-tailed deer, orwhite-tailed deer:white-tailed deer across allseasons. There was no difference in indices ofoverlap of home ranges among seasons (F2 5

0.51, P 5 0.68) or mule deer:mule deer, muledeer:white-tailed deer, or white-tailed deer:white-tailed deer (F2 5 0.74, P 5 0.48), norwas there a season and year interaction (F6 5

0.64, P 5 0.70).

DISCUSSION—Because we were unable to trackdeer during the breeding season, we may haveunderestimated size of home range for the year.Our results did not support our initial predic-tions that the sizes of home ranges would differand that overlap would be considerable. Accord-ing to competition theory, species with similarlife-history traits should partition resources whenthey are sympatric if coexistence is to occur(Hardin, 1960). Differences in preference anduse of forage do not appear to be the mechanismfacilitating coexistence of these species (Hill andHarris, 1943; Allen, 1968; Martinka, 1968; Kraus-man, 1978), so some other resource (e.g., space)must be driving resource partitioning, at anunknown scale. Equivalent sizes and overlap ofhome range suggests both species exist on thesame forage without partitioning, particularlyduring periods of low availability of forage.Rainfall during our study was 18 cm belowaverage; drought may have narrowed any differ-

Size of home range (MCP) Year Season n Mean SE


2001 Spring 15 4.30 0.88Summer 14 2.52 0.49

2002 Spring 16 4.67 0.60Summer 17 1.94 0.40

Mean seasonal Spring 16 4.32a 0.77Summer 19 2.08b 0.23

Annual 16 1.77 0.26

TABLE 2—Seasonal fidelity (mean indices of overlap) within years in core areas (km2) calculated using the 50%fixed-kernel method and in home ranges (km2) determined using the 95% fixed-kernel method for female muledeer (Odocoileus hemionus) and white-tailed deer (O. virginianus) in west-central Texas, 2000–2002.

Year

Mule deer White-tailed deer

Mean SE n Mean SE n

Size of core areas

2000 30.80 9.98 7 15.38 9.58 92001 30.44 6.51 14 31.61 7.06 142002 19.59 5.09 15 25.54 6.38 17All years 25.99 3.82 36 25.38 4.25 40

Size of home ranges

2000 69.36 6.34 7 58.76 6.71 92001 70.38 6.14 14 72.03 3.37 142002 66.06 4.24 15 69.62 3.81 17All years 68.38 3.15 36 68.02 2.57 40

TABLE 1—Continued.


ence in size of home range between species.Because of their larger body mass, mule deershould require larger home ranges than sympat-ric white-tailed deer, but productivity of habitatappears to have a greater impact on actual size ofhome range of ungulates (Relyea et al., 2000).Home ranges tend to be larger as habitatsbecome more xeric (Wood et al., 1989); howev-er, female mule deer in this study had smallerhome ranges than mule deer in other semi-aridand arid regions. In a sympatric area of Montana,

average size of home range of non-migratoryfemale mule deer was 6.30 6 0.61 km2. Similarly,home ranges were smaller than those reportedfor female mule deer in western Arizona(daytime mean 5 32.3 km2, night 5 25.5 km2;Hayes and Krausman, 1993) and southwesternArizona (121 km2; Rautenstrauch and Kraus-man, 1989). However, estimates from this studywere comparable to those from a sympatric areaof southwestern Texas (mean 5 3.8 km2; Dick-inson and Garner, 1979). Size of home range of

TABLE 4—Mean indices of overlap in core areas (km2) calculated using the 50% fixed-kernel method and inhome ranges (km2) determined using the 95% fixed-kernel method for female mule deer (Odocoileus hemionus)and white-tailed deer (O. virginianus) in west-central Texas, 2000–2002. Indices were compared with and betweenspecies. Means followed by different capital letters across rows, and different lower-case letters within columns,were different at a 5 0.05.

Year Season

Mule deer:mule deerWhite-tailed deer:white-tailed deer

Mule deer:white-tailed deer

Mean SE n Mean SE n Mean SE n

Size of core area

2001 Spring 10.52 3.81 19 16.00 5.77 22 5.54ab 1.91 35Summer 6.11 3.40 14 6.22 3.03 26 10.44a 3.52 26

2002 Spring 14.89A 5.53 21 14.86A 4.47 30 0.77bB 0.54 31Summer 10.01 4.80 14 15.96 6.43 14 8.82a 3.88 12

Combined Spring 12.81A 3.40 40 15.34A 3.52 52 3.30B 1.08 66Summer 8.06 2.9 28 9.63 3.03 40 9.93 2.68 38

Size of home range

2001 Spring 36.33 5.21 19 34.76 7.03 22 30.96 4.01 35Summer 34.70 8.37 14 28.73 5.36 26 33.51 5.73 26

2002 Spring 34.04 4.75 21 38.52 5.11 30 27.51 3.61 31Summer 34.35 6.36 14 45.24 5.94 14 36.08 7.74 12

Combined Spring 35.12 3.47 40 36.93 4.15 52 29.34 2.71 66Summer 34.52 5.16 28 34.51 4.20 40 34.32 4.56 38

TABLE 3—Mean indices of overlap in core areas (km2) calculated using the 50% fixed-kernel method and inhome ranges (km2) determined using the 95% fixed-kernel method for individual female mule deer (Odocoileushemionus) and white-tailed deer (O. virginianus) in west-central Texas, spring and summer 2000–2002. Meansfollowed by different letters across rows were different at a 5 0.05.

Season

Mule deer White-tailed deer

Mean SE n Mean SE n

Size of core areas

Spring–spring 32.19a 5.51 9 16.60b 5.05 25Summer–summer 26.81a 4.72 19 9.53b 3.29 25

Size of home ranges

Spring–spring 58.45 6.63 19 42.87 6.81 25Summer–summer 59.75 7.03 19 41.44 7.06 25


white-tailed deer in our study was similar toestimates determined using the minimum-con-vex-polygon method for white-tailed deer innortheastern Mexico (2.06 6 0.13 km2; Gallinaet al., 1997), but were smaller than those ofwhite-tailed deer in a sympatric area of Montana(33.48 6 6.22 km2; Wood et al., 1989). Smallhome ranges may indicate that densities arerelatively high on our study area, possibly due tolack of predators and low hunting pressure, ashigh densities of ungulates have been correlatednegatively with size of home range in ungulates(Marshall and Whittington, 1969). Furthermore,intraspecific and interspecific competition tendto compress size of home range in ungulates(Courtois et al., 1998).

The high degree of interspecific overlap inhome range or when it did not occur indicatedthat habitat partitioning may have occurred on afiner temporal or spatial scale than can bedetected by home-range-level analyses. Interspe-cific overlap during summer was greater during2001 when spring rainfall was below normal, anddecreased in 2002 when spring rainfall andsubsequent production of forage were average.That interspecific overlap in home range was lessthan intraspecific overlap in spring, suggests thatthe species segregate to a greater extent whenresources are more abundant. Preferences forforage by both species became more divergentduring droughts in Arizona, which may permitgreater spatial overlap during drought (Anthony,1976) because if diet is more diverse deer wouldcover larger areas. It is possible that competitionfor forage forced both species to forgo normalspatial avoidance during dry periods. Overlap incore area provides a greater potential forcompetition between species and conspecifics(Wauters and Dhondt, 1985). Greater avoidanceof core areas of other species compared toconspecifics may indicate that interspecific com-petition influenced spatial distribution of indi-vidual deer more than did intraspecific compe-tition. Both species appeared to maintain homeranges within the same general area during bothyears, suggesting spatial coexistence was stableand neither species actively drove the other outof the area. However, white-tailed deer showedmore tendency to shift home range betweenseasons, similar to sympatric female white-taileddeer in Montana, which frequently shifted homeranges in consecutive years (Wood et al., 1989).Competition from both mule deer and conspe-

cifics may be the cause of shifts among seasons,as adult deer shift core areas in search ofincreased resources or to avoid competitors(Lesage et al., 2000).

Avey et al. (2003) indicated that there washabitat separation between species, suggestingthat managers might be able to manage habitatfor both species. However, the high degree ofoverlap in home range that we observed suggeststhat habitat management to primarily benefitonly one species may be difficult to conduct on alarge scale (e.g., an entire ranch). These speciesdid not appear to maintain separate distributionson a home-range scale despite similarities in lifehistory and selection of forage that suggest suchseparation might be necessary for long-termcoexistence. Finer-scale selection of habitat maybe the driving mechanism behind coexistence ofboth species in this area and warrants furtherinvestigation.

We thank C. Anderson, J. Brunjes, S. Dempsey, B.Hudgens, S. Petersen, R. Philips, and the L. D. Clarkfamily for logistic support and field assistance. R.Carrera provided the Spanish translation. Funding andsupport for this research was provided by Texas Parksand Wildlife Department, Rob and Bessie WelderWildlife Foundation, and the West Texas and Houstonchapters of Safari Club International. This is College ofAgricultural Sciences and Natural Resources technicalpublication T-9-1137.

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Submitted 15 August 2007. Accepted 16 September 2008.Associate Editor was Troy L. Best.


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