Winter Macro- and Microhabitat Use of Winter Roost Sites in Central Missouri

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1 Ntionl Quil Symposium Proceedings Volume 5 Article Winter Mcro- nd Microhbitt Use of Winter Roost Sites in Centrl Missouri Eliodor Chmberlin University of Missouri Ronld D. Drobney University of Missouri Thoms V. Diley Missouri Deprtment of Conservtion Follow this nd dditionl works t: Recommended Cittion Chmberlin, Eliodor; Drobney, Ronld D.; nd Diley, Thoms V. (2002) "Winter Mcro- nd Microhbitt Use of Winter Roost Sites in Centrl Missouri," Ntionl Quil Symposium Proceedings: Vol. 5, Article 25. Avilble t: This Hbitt Mngement is brought to you for free nd open ccess by Trce: Tennessee Reserch nd Cretive Exchnge. It hs been ccepted for inclusion in Ntionl Quil Symposium Proceedings by n uthorized editor of Trce: Tennessee Reserch nd Cretive Exchnge. For more informtion, plese contct trce@utk.edu.

2 Chmberlin et l.: Winter Mcro- nd Microhbitt Use of Winter Roost Sites in Centr WINTER MACRO- AND MICROHABITAT USE OF WINTER ROOST SITES IN CENTRAL MISSOURI Eliodor Chmberlin Deprtment of Fisheries nd Wildlife Sciences, 302 Anheuser-Busch Nturl Resources Building, University of Missouri, Columbi, MO , USA Ronld D. Drobney U.S. Geologicl Survey, Missouri Coopertive Fish nd Wildlife Reserch Unit, 302 Anheuser-Busch Nturl Resources Building, University of Missouri, Columbi, MO , USA Thoms V. Diley Missouri Deprtment of Conservtion, 1110 South College Avenue, Columbi, MO 65201, USA ABSTRACT Northern bobwhite (Colinus virgininus) mngers nd biologists hve expressed concern regrding the pprent decline of northern bobwhite popultions throughout the Unites Sttes. The decline hs been ttributed to hbitt loss; however, the decline my be the result of multiple fctors. Severl studies concluded tht reproduction ws not limiting fctor, nd recommended tht investigtions of winter hbitt use t the microhbitt level re needed. In our study, we used dt from 166 roost sites obtined from 194 rdiomrked bobwhites to nlyze winter mcrohbitt use nd microhbitt chrcteristics of roosts selected by bobwhites in centrl Missouri. At the mcrohbitt level, bobwhites showed preference for erly successionl vegettion (ESV), ntive wrm-seson grss (NWSG), nd old (idle) fields. Most roost loctions (5l.2%) were in old fields, in ESV (23%), nd NWSG (l7%). For ll 3 hbitt types (old fields, ESV, NWSG), litter t the roost site ws higher (P 0.05) thn the surrounding vegettion. In the 2 most preferred hbitt types, visul obstruction reding (VOR) nd mximum vegettion height were higher (P 0.05) thn the surrounding vegettion. In NWSG nd old fields, litter depth ws significntly higher (P 0.05) thn the surrounding vegettion. Hbitt mngement of winter cover in centrl Missouri will benefit from the mintennce of dense ground litter ( 65%), tll vegettion ( 91 cm), VOR (29 cm), nd litter depth bout 1.5 cm in ESV, NWSG, nd old fields. Cittion: Chmberlin, E., R. D. Drobney, nd T. V. Diley Winter mcro- nd microhbitt use in centrl Missouri. Pges in S. J. DeMso, W. P. Kuvlesky, Jr., F. Hernández, nd M. E. Berger, eds. Quil V: Proceedings of the Fifth Ntionl Quil Symposium. Texs Prks nd Wildlife Deprtment, Austin, TX. Key words: Colinus virgininus, mcrohbitt, microhbitt, Missouri, northern bobwhite, winter hbitt 140 INTRODUCTION The bundnce of northern bobwhites hs declined in North Americ t rte of 2.4% per yer, nd continues to decline (Robbins et l. 1986, Droege nd Suer 1990, Brennn 1991, Church et l. 1993). Bobwhite popultions in Missouri hve shown similrly declines (Diley nd Truitt 1998). The decline hs been ttributed to hbitt loss nd degrdtion (Dixon et l. 1996). Efforts to restore bobwhite popultions hve emphsized the need to understnd sesonl hbitt needs (Burger et l. 1994). During the 1930 s Errington nd Hmerstrom (1936) nd Stoddrd (1931:45) conducted the first winter hbitt studies of northern bobwhites. These studies were descriptive, but stimulted dditionl reserch on bobwhite winter ecology. Klimstr nd Ziccrdi (1963) were the first to describe bobwhite winter hbitt selection by nlyzing roost-site microhbitt chrcteristics. In Illinois frmlnd, bobwhites selected winter roost-sites with men vegettion height of 59 cm nd density of 181 stems/m 2. In the Oklhom tllgrss pririe, bobwhites selected roosts with mximum height of 68 cm nd density of 136 stems/m 2 (Wisemn nd Lewis 1981). In Missouri frmlnd, bobwhite winter roosts were chrcterized s 27% forb cover nd 23% bre ground (Burger et l. 1994). The objective of this study ws to determine mcro- nd microhbitt use of bobwhite winter roost-sites in Sline County, Missouri. We lso developed roosting hbitt models for old fields, ESV, nd NWSG. METHODS Study Are The study ws conducted t the Blind Pony Conservtion Are (BPCA) in Sline County, Missouri. Blind Pony Conservtion Are is mnged for northern bobwhites with hbitt mngement focused on erly successionl stge vegettion. The plnt diversity on BPCA provided n opportunity for bobwhites to select mong wide rnge of cover densities nd hbitt types. Blind Pony Conservtion Are contins mny smll fields seprted by reltively smll ptches of woody cover. Stnds of NWSG were distributed Published by Trce: Tennessee Reserch nd Cretive Exchnge,

3 Ntionl Quil Symposium Proceedings, Vol. 5 [2002], Art. 25 BOBWHITE WINTER HABITAT 141 throughout the re. Ntive wrm-seson grss stnds were vegetted by Indin grss (Sorghstrum spp.), big bluestem (Andropogon gerrdii), little bluestem (Andropogon scoprius), nd switchgrss (Pnicum virgtum). Woody vegettion consisted of ok trees (Quercus spp.), multiflor rose (Ros multiflor), red cedr (Juniperus virginin), nd blckberry (Rubus spp.). Croplnd is common with corn, soyben, whet/ lespedez (Lespedez spp.). Three to 6 m of crop field borders re unhrvested. Food plots contining millet were interspersed mong old fields nd stnds of NWSG. We used Roseberry nd Klimstr s (1984:13 15) criteri for defining old fields (idle) s 2 to 3-yer old trcts dominted by perennil vegettion, nd chrcterized by incresing mounts of woody vegettion nd decresing nnul species such s rgweed (Ambrosi spp.). On the study re, old fields consisted of goldenrod (Solidgo spp.), smrtweed (Polygonum spp.), sters (Aster spp.), ok splings, red cedr (Juniperus virginin), mple (Acer spp.), nd hickory (Cry spp.). Erly successionl fields were dominted by nnuls such s rgweed, lespedez, foxtil (Setri spp.), dropseed (Sporobolus spp.), nd millet (Roseberry nd Klimstr 1984:13 15, 31). Cool-seson grsses (CSG) consisted of crbgrss (Digitri spp.), brome (Bromus spp.), nd fescue (Festuc spp.). Covey Loctions The study of roost site selection nd hbitt chrcteristics ws conducted from Jnury through Mrch We rndomly selected 3 5 rdiomrked bobwhites ech dy from popultion of 194 rdiomrked bobwhites on the BPCA (11 16 coveys). From 0300 until 1 hour before sunrise, we determined the loction of ech covey. The generl re ws flgged, so we could find roost fecl piles t dylight. We recorded mbient temperture (minimum/mximum), snow depth, soil temperture, precipittion (presence/bsence), wind speed (mesured with hnd-held wind guge), nd wind direction bout 15 m from the estimted covey loction. If the ground ws frozen, we recorded soil temperture s 0 C. During dylight serches for roosts, we identified the previous night s roost from the freshest fecl pile (e.g., contining no frost). Vegettion Mesurements To determine whether microhbitt chrcteristics of roosts differed from tht of surrounding vegettion, we mesured the microhbitt chrcteristics of 4 rndomly selected points in the field contining ech roost. The rndom sites were chosen by plcing grid scled t 15-m intervls over n eril photogrph of the roost fields, nd rndomly selected 4 sites. We mesured VOR using the method described by Robel et l. (1970). A Dubenmire frme ws used to mesure percent cnopy cover (CC), mximum vegettion height (MH), percent bsl cover of the vegettion (BC), percent bre ground (BG), percent snow cover (SC), snow depth (SD), percent litter cover (LC), nd litter depth (LD)(Dubenmire 1959). We estimted LD by verging 5 rndom mesurements within the Dubenmire frme. The sme procedure ws used to estimte SD. Sttisticl Anlyses Mcrohbitt Use nd Preference. Using PC ArcView nd ARC/INFO, we developed lnd use/ lnd cover sptil dt lyer for the BPCA. We used this dt lyer to quntify the extent of lnd cover types in h. Supporting informtion, including rods, strems, nd section lines were used s loction references for estblishing the boundries of the study re. Reltive preference indices were clculted s described by Tylor nd Guthery (1980), Wisemn nd Lewis (1981), Byers et l. (1984), nd Anderson nd Gutzwiller (1994). Indices indicte hbitt preference rnging from highly preferred ( 10) to voidnce ( 10). We estimted hbitt vilbility s the proportion of the study re covered by ech hbitt type, defined by the dominnt vegettion (Thompson nd Fritzell 1988, Jnvrin 1991, Anderson nd Gutzwiller 1994). Reltive use of hbitt types ws determined by the proportion of telemetry loctions recorded in ech hbitt type. Microhbitt Use. To ssess the influence of microhbitt vribles on roost site selection, we used stepwise logistic regression (SAS Institute 1990) to determine how independent vribles relte to microhbitt selection cross rnge of low mbient tempertures. We selected 9 independent vribles priori tht we predicted might be relted to bobwhite microhbitt selection. Ech hbitt type ws modeled seprtely, nd the nlysis progressed by introducing 1 independent vrible t time. The probbility rejection level ws 0.10 to determine the best model. We used multivrite nlysis to detect differences (P 0.05) in microhbitt vribles between roost nd rndom sites. The men of the 4 rndom sites ws compred with the corresponding chrcteristics of the roost site. RESULTS From Jnury through Mrch , we mesured 166 roost sites from 194 rdiomrked bobwhites. Individul bobwhite coveys did not use the sme roost more thn once. During the study, dily minimum mbient tempertures rnged from 20 to 13 C, nd recorded wind velocities did not exceed 13 m/sec. Mcrohbitt Use nd Preference Bobwhites roosted in old fields more thn ny other hbitt type. Old fields ccounted for 51% of roost sites, compred to 24% in ESV, nd 17% in NWSG (Tble 1). Despite the high intensity of use of old fields, reltive-use dt indicted tht bobwhites preferred ESV nd NWSG to old fields (Tble 2). Woody vegettion, griculturl fields, nd CSG were used in- 2

4 Chmberlin et l.: Winter Mcro- nd Microhbitt Use of Winter Roost Sites in Centr 142 CHAMBERLAIN ET AL. Tble 1. Percentge nd number of northern bobwhite roost sites in 6 types of vegettion on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr, Hbitt type Totl *Old fields *ESV *NWSG b Woody vegettion Crop fields Cool-seson grss Totl number of roosts 47% (22) 26% (12) 19% (9) 6% (3) 2% (1) 0% (0) 47 53% (63) 23% (27) 16% (19) 4% (5) 3% (4) 1% (1) 119 * The 3 vegettion types used for ll sttisticl nlyses. ESV represents erly successionl vegettion. b NWSG represents ntive wrm-seson grss. 51% (85) 23% (39) 17% (28) 5% (8) 3% (5) 1% (1) 166 Tble 2. Reltive preference of northern bobwhite roosts in 6 types of vegettion on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr, Hbitt type Old fields ESV NWSG b Woody vegettion Crop fields Cool-seson grss Proportion vilble Proportion used ESV represents erly successionl vegettion. b NWSG represents ntive wrm-seson grss. Reltive preference frequently, nd ccounted for combined totl 10% of the roost sites (Tble 1). Microhbitt Chrcteristics Roost Sites vs. Rndom Sites. We nlyzed roost microhbitt chrcteristics for ech hbitt type, nd there were severl influentil microhbitt vribles. Using the SWLR procedure, the probbility ( p) ofn old field site being bobwhite roost ws: ln (p/1 p) CC 0.28LD 0.02BC. The probbility of site being roost site in ESV ws: ln (p/1 p) VOR 0.02MH 0.03BG. In NWSG, the probbility (p) of site being bobwhite roost ws: ln (p/1 p) MH 0.02LC (Tble 3). We compred roost nd rndom site chrcteristics to determine if roosts differed from the surrounding field. Old field roosts hd lower CC (37%), BC (31%) nd SC (14%) thn the rndom sites (P 0.05). Litter depth (1.65 cm) nd LC (79%) were higher (P 0.05) t roosts (Tble 4). Roosts in erly successionl vegettion hd higher VOR (21 cm), MH (94 cm), LC (65%) nd BG (13%) thn rndom sites (P 0.05). Snow depth (0.40 cm) nd snow cover (19%) were lower (P 0.05) t roost sites (Tble 5). Roosts in NWSG hd higher VOR (29 cm), MH (106 cm), LD (1.44 cm) nd LC (67%) thn rndom sites (P 0.05) (Tble 6). DISCUSSION Although there ws greter proportion of old fields on BPCA, bobwhites roosted in ESV 4 times more often thn expected bsed upon the proportionl vilbility of this cover type, nd used old fields nd NWSG t lmost twice their proportionl vilbility. Preference for ESV supports the findings of studies conducted in Illinois (Klimstr nd Ziccrdi 1963) nd Missouri (Burger et l. 1994). The high reltive use rnking of NWSG on our study re seems consistent with the findings of study conducted in Oklhom (Wisemn nd Lewis 1981), tht showed high numbers of roosts in ntive grsslnds. Tonkovich nd Stuffer (1993) ttributed the preference of bobwhite for ESV nd NWSG to the vilbility of high energy seeds such s lespedez, rgweed, milo, nd millet. We believe the greter vilbility of such seeds in close proximity to roost sites my ugment bobwhite overwinter survivl by reducing the mount of time spent forging; therefore incresing forging efficiency nd reducing exposure to predtors. Our study results indicte tht lthough northern bobwhites utilize vriety of hbitt types for roosting, microhbitt chrcteristics of selected winter roosts differ significntly from tht of the surrounding vegettion. Of the 9 microhbitt vribles mesured, LC ws the only vrible tht differed from the rndom sites for ll 3 hbitt types. This finding is not in ccordnce with other studies (Klimstr nd Ziccrdi 1963, Burger et l. 1994), which found tht bobwhites utilized roosts with little to no litter ccumultion. The difference between our LC results nd others could be ttributed to litter vilbility resulting from different mngement prctices. At BPCA, NWSG stnds were burned on 3 5 yer rottion, nd hying ws limited. Litter biomss hs been found to decrese immeditely following burn, nd then increse s the time since Tble 3. Stepwise logistic regression predicting the occurrence of northern bobwhite winter roosts in old fields, erly successionl vegettion, nd ntive wrm-seson grss on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr Hbitt type Microhbitt vribles Old fields Cnopy cover Litter depth Bsl cover Erly successionl vegettion VOR b Mximum height Bre ground Ntive wrm-seson grss Mximum height Litter cover Coefficient Odds rtio 2 P Intercept for the liner portion of the logistic regression eqution. b VOR represents visul obstruction reding. Published by Trce: Tennessee Reserch nd Cretive Exchnge,

5 Ntionl Quil Symposium Proceedings, Vol. 5 [2002], Art. 25 BOBWHITE WINTER HABITAT 143 Tble 4. Microhbitt chrcteristics of northern bobwhite roosts nd rndom sites in old fields on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr, Vlues displyed re lest squres men lest squres stndrd error (SE). Microhbitt vribles VOR (cm) Mximum height (cm) Cnopy cover (%) Litter depth (cm) Percent cover of litter (%) Percent bsl cover (%) Percent bre ground (%) Snow depth (cm) Percent snow cover (%) VOR represents visul obstruction reding. * Denotes significnt difference. x Roost sites (n 87) SE Rndom sites (n 313) x SE P * * the burn progresses (Gibson 1988). Litter lso ccumultes rpidly with plnting ge. Four to 6 yers fter plnting, litter ccumultion leveled off t 70% (Burger et l. 1994). In ESV nd NWSG, bobwhites utilized roosts chrcterized by tll vegettion (94 nd 106 cm, respectively), which ws tller thn the surrounding vegettion. Roosts in Illinois hd men vegettion height of 59 cm (Klimstr nd Ziccrdi 1963), which is considerbly lower thn the men vegettion height used by bobwhites on the BPCA. In northest Oklhom, roosts were chrcterized by n verge height of 68 cm (Wisemn nd Lewis 1981). The differences in vegettion chrcteristics of roosts might be ttributed to study site differences in plnt species composition, differences in winter severity mong regions, nd differences resulting from differences in methodology. Our study described winter roost chrcteristics t mcro- nd microhbitt levels. Severl of the significnt microhbitt vribles (LC, LD, MH, VOR) my contribute to the therml vlue of winter roosts. For exmple, tll vegettion reduces convective het loss to the environment, where dense litter cover nd depth minimizes conductive het loss to the soil (Geiger 1965: , Kendeigh 1969, Cmpbell nd Normn 1998:72). Vegettion height nd density not only minimize wind velocity t the level of the roost, but perhps more importntly, reduces the loss of long-wve rdition (Geiger 1965: , , ; Cmpbell nd Normn 1998:231). During the dy, vegettive cover bsorbs both the counter-rdition of the sky nd terrestril rdition rising from the ground. At night, the mount of rdition bsorbed during the dy is lost; however, the rte t which it is lost depends upon vegettion height nd CC (Geiger 1965: , 362; Cmpbell nd Normn 1998: ). Although the microhbitt chrcteristics of selected roost sites pper to be relted to their fvorble therml chrcteristics, more reserch is needed to determine the specific reltionships between bobwhite thermosttic energy demnds nd winter. Other ecologicl components such s depredtion nd food vilbility must lso be considered when exmining bobwhite winter hbitt selection nd survivl. Depredtion is the most pprent proximte cuse of fll-spring bobwhite mortlity in Missouri. Burger (1993) reported tht mmmlin depredtion (21.6%) nd vin depredtion (25.2%) were the primry cuses of bobwhite mortlity in Missouri (Burger 1993). Therefore, bobwhite hbitt selection is probbly ttributed to other fctors, such s cover chrcteristics tht reduce the risk of depredtion. Ultimtely, Tble 5. Microhbitt chrcteristics of northern bobwhite roosts nd rndom sites in erly successionl vegettion on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr, Vlues displyed re lest squres men lest squres stndrd error (SE). Microhbitt vribles VOR (cm) Mximum height (cm) Cnopy cover (%) Litter depth (cm) Percent cover of litter (%) Percent bsl cover (%) Percent bre ground (%) Snow depth (cm) Percent snow cover (%) VOR represents visul obstruction reding. * Denotes significnt difference. x Roost sites (n 39) SE Rndom sites (n 140) x SE P * * * *

6 Chmberlin et l.: Winter Mcro- nd Microhbitt Use of Winter Roost Sites in Centr 144 CHAMBERLAIN ET AL. Tble 6. Microhbitt chrcteristics of northern bobwhite roosts nd rndom sites in ntive wrm-seson grss on Blind Pony Conservtion Are, Sline County, Missouri, Jn Mr, Vlues displyed re lest squres men lest squres stndrd error (SE). Microhbitt vribles VOR (cm) Mximum height (cm) Cnopy cover (%) Litter depth (cm) Percent cover of litter (%) Percent bsl cover (%) Percent bre ground (%) Snow depth (cm) Percent snow cover (%) VOR represents visul obstruction reding. * Denotes significnt difference. x Roost sites (n 28) SE Rndom sites (n 97) x SE P * * * winter hbitt selection is likely the result of multiple fctors, nd bobwhites probbly select winter hbitts tht mximize bioenergetic dvntges nd predtor voidnce, optimize distnce from nerby coveys, nd increse ccessibility to food resources (Roseberry nd Klimstr 1984:23 35). These chrcteristics of winter hbitt collectively enhnce the potentil winter survivl of northern bobwhites. ACKNOWLEDGMENTS Finncil support for the project ws funded by the Chncellor s Gus T. Ridgel Fellowship, George Wshington Crver Fellowship, Missouri Deprtment of Conservtion Scholrship-Internship, Quil Unlimited in Missouri, nd Phesnts Forever in Missouri. This is contribution from the Missouri Coopertive Fish nd Wildlife Reserch Unit (Missouri Deprtment of Conservtion, University of Missouri, United Sttes Geologicl Survey, nd Wildlife Mngement Institute cooperting). We re grteful to Deli M. Grci for editing this mnuscript. LITERATURE CITED Anderson, S. H., nd K. J. Gutzwiller Hbitt evlution methods. Pges in T. A. Bookhout, ed. Reserch nd mngement techniques for wildlife nd hbitts. Allen Press Incorported, Lwrence, Knss. Brennn, L. A How cn we reverse the northern bobwhite popultion decline. Wildlife Society Bulletin 19: Burger, L. W., Jr Bobwhite survivl nd reproductive ecology. Disserttion. University of Missouri, Columbi. Burger, L. W., Jr., M. R. Ryn, E. W. Kurzejeski, nd T. V. Diley Fctors ffecting the hbitt vlue of CRP lnds for northern bobwhite in northern Missouri. Proceedings of the NCT-163 Post Conservtion Reserve Progrm Lnd Use Conference. Denver, Colordo. Byers, C. R., R. K. Steinhorst, nd P. R. Krusmn Clrifiction of technique for nlysis of utiliztion-vilbility dt. Journl of Wildlife Mngement 48: Cmpbell G. S., nd J. M. Normn An Introduction to Environmentl Biophysics. Springer-Verlg, New York, New York. Church, K. E., J. R. Suer, nd S. Droege Popultion trends of quils in North Americ. Proceedings of the Ntionl Quil Symposium 3: Diley, T. V., nd V. L. Truitt Annul bobwhite quil popultion nd hunter surveys. Performnce Report. Missouri Federl Aid Project Number W-13-R-52. Dubenmire, R. K A cnopy coverge method of vegettionl nlysis. Northest Scientist 43: Dixon, K. R., M. A. Horner, S. R. Anderson, W. D. Henriques, D. Durhm, nd R. J. Kendll Northern bobwhite hbitt use nd survivl on South Crolin plnttion during winter. Wildlife Society Bulletin 24: Droege, S., nd J. R. Suer Northern bobwhite, gry prtridge, nd ring-necked phesnt popultions trends ( ) from the North Americn Breeding Bird Survey. Pges 2 20 in K. E. Church, R. E. Wrner, nd S. J. Brdy, eds. Perdix V: Gry prtridge nd ring-necked phesnt workshop. Knss Deprtment of Wildlife nd Prks, Empori. Errington, P. L., nd F. N. Hmerstrom, Jr The northern bobwhite s winter territory. Iow Agriculturl Experimentl Sttion. Reserch Bulletin 201: Geiger, R The climte ner the ground. Hrvrd University Press. Cmbridge, Msschusetts. Gibson, D. J Regenertion nd fluctution of tllgrss pririe vegettion in response to burning frequency. Bulletin Torrey Botnicl Club 115:1 12. Jnvrin, J. A Movements of northern bobwhites in response to hunting pressure nd evlution of drive counts for estimting quil densities. Thesis. University of Missouri, Columbi. Kendeigh, S. C Energy responses of birds to their therml environments. Wilson Bulletin 81: Klimstr, W. D., nd V. C. Ziccrdi Night-roosting hbitt of bobwhites. Journl of Wildlife Mngement 27: Robbins, C. S., D. Bystrk, nd P. H. Geissler The breeding bird survey: its first fifteen yers, United Sttes Fish nd Wildlife Service Resource Publiction 157. Robel, R. J., J. N. Briggs, A. D. Dyton, nd L. C. Hulbert Reltionships between visul obstruction mesurements nd weight of grsslnd vegettion. Journl of Rnge Mngement 23: Roseberry, J. L., nd W. D. Klimstr Popultion ecology of the bobwhite. Southern Illinois University Press, Crbondle. SAS Institute, Inc SAS Procedures Guide-Version 6. Third edition. Cry, North Crolin. Stoddrd, H. L The bobwhite quil: its hbits, preservtion, nd increse. Chrles Scribner s Sons, New York, New York. Published by Trce: Tennessee Reserch nd Cretive Exchnge,

7 Ntionl Quil Symposium Proceedings, Vol. 5 [2002], Art. 25 BOBWHITE WINTER HABITAT 145 Tylor, M. A., nd F. S. Guthery Fll-winter movements, rnges, nd hbitt use of lesser pririe chickens. Journl of Wildlife Mngement 44: Thompson, F. R., nd E. K. Fritzell Ruffed grouse winter roost sites preference nd influences on energy demnds. Journl of Wildlife Mngement 52: Tonkovich, M. J., nd D. F. Stuffer Evluting microhbitt selection by northern bobwhite in Virgini. Proceedings of the Annul Conference of Southestern Assocition of Fish nd Wildlife Agencies 47: Wisemn, D. S., nd D. C. Lewis Bobwhite use of hbitt in tllgrss rngelnd. Wildlife Society Bulletin 9: