Food habits of 407 coyotes (Canis latrans), intermittently collected in southern Texas from March 1994 to January 1997, were determined from coyote stomachs. Mammalian prey was the most prevalent diet item as calculated by frequency of occurrence and aggregate percent methods, followed by insects, vegetation, birds, and reptiles. The remains of northern bobwhite (Colinus virginianus) or their eggs were found in only 12 coyote stomachs, which constituted 1% of the coyote diet as calculated by the aggregate percent method. Northern bobwhite appear to be an incidental prey item for coyotes in southern Texas. Therefore, coyote removal programs designed to lessen quail depredation appear unwarranted

Henke, Scott E.

English

University of Tennessee, Knoxville: Trace

National Quail Symposium Proceedings Volume 5 Article 7 2002 Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas Scott E. Henke Texas A&M University Follow this and additional works at: https://trace.tennessee.edu/nqsp Recommended Citation Henke, Scott E. (2002) "Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas," National Quail Symposium Proceedings: Vol. 5 , Article 7. Available at: https://trace.tennessee.edu/nqsp/vol5/iss1/7 This Impacts of Depredation on Quail is brought to you for free and open access by Volunteer, Open Access, Library Journals (VOL Journals), published in partnership with The University of Tennessee (UT) University Libraries. This article has been accepted for inclusion in National Quail Symposium Proceedings by an authorized editor. For more information, please visit https://trace.tennessee.edu/nqsp. 57COYOTES: FRIEND OR FOE OF NORTHERN BOBWHITE INSOUTHERN TEXASScott E. HenkeCaesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USAABSTRACTFood habits of 407 coyotes (Canis latrans), intermittently collected in southern Texas from March 1994 to January 1997, weredetermined from coyote stomachs. Mammalian prey was the most prevalent diet item as calculated by frequency of occurrence andaggregate percent methods, followed by insects, vegetation, birds, and reptiles. The remains of northern bobwhite (Colinus virginianus)or their eggs were found in only 12 coyote stomachs, which constituted1% of the coyote diet as calculated by the aggregate percentmethod. Northern bobwhite appear to be an incidental prey item for coyotes in southern Texas. Therefore, coyote removal programsdesigned to lessen quail depredation appear unwarranted.Citation: Henke, S. E. 2002. Coyotes: Friend or foe of northern bobwhite in southern Texas. Pages 57–60in S. J. DeMaso,W. P. Kuvlesky, Jr., F. Hernández, and M. E. Berger, eds. Quail V: Proceedings of the Fifth National Quail Symposium. Texas Parksand Wildlife Department, Austin, TX.Key words: Canis latrans, Colinus virginianus, coyote, depredation, food habits, northern bobwhite, TexasINTRODUCTIONNorthern bobwhite populations have been declin-ing throughout most of their range and there is concernthat bobwhites could be extirpated in the southeasternUnited States by 2005 (Brennan 1991). Depredationhas been reported as the major source of mortality forbobwhites at every life stage (Rollins and Carroll2001). Coyotes are typically listed among the commonpredators of bobwhite and their eggs (Beasom 1974,Lehmann 1984:190, Guthery 1995, Herna´ndez et al.1997, Rollins and Carroll 2001, Wallace 2001).Coyotes are opportunistic and generalist predators(MacCracken and Hansen 1987) and their diet oftendiffers widely from one area to another (Bekoff 1977).In an extensive literature review of diet across 17 west-ern states, coyote diets averaged 33% lagomorph, 25%carrion, 18% rodent, and 13.5% domestic livestock(Sperry 1941). However, Lehmann (1946) reportedthat 37% (n 14) of the coyote diet during springand summer in southern Texas consisted of bobwhitesand their eggs. Lehmann (1946) concluded that coy-otes were the primary predator of bobwhite nests insouthern Texas; however, his sample sizes were toosmall to generate little confidence in that conclusion.My objective was to report coyote food habitsfrom a large sample (n  407) of coyotes collected insouthern Texas. The coyotes used for this report werecollected for other research projects.STUDY AREASCoyotes were collected on 7 ranches in southernTexas, which included the Santa Gertrudis Division ofthe King Ranch (Kleberg Co.), the Callaghan Ranch(Webb Co.), La Mesa Ranch (Webb Co.), Heard Ranch(Webb Co.), Duval Ranch (Duval Co.), CameronRanch (La Salle Co.), and La Campana Ranch(McMullen Co.). All collection areas consisted of pri-vately owned rangeland used primarily for cattle andoil production.Mean annual rainfall for southern Texas is 40–90cm, increasing from west to east. Temperatures rangefrom 8 C in January to 38 C in July. During thecollection period the area experienced average rainfalland temperatures, with 1995 being slightly wetter thanaverage and 1996 being dryer than average (http://climate.tamu.edu/bclimateDQ/stationsel/stationnameA.html).Originally the region supported a grassland-savan-nah climax community (Fulbright 2001), but grazing,suppression of fire, and other factors have resulted inplant communities dominated by dense stands of hon-ey mesquite (Prosopis glandulosa), blackbrush (Aca-cia rigidula), Texas prickly pear (Opuntia lindhei-meri), whitebrush (Aloysia lycioides), and spiny hack-berry (Celtis pallida). Potential prey items for coyoteson the study areas included white-tailed deer (Odo-coileus virginianus), javelina (Tayassu tajacu), rac-coon (Procyon lotor), striped skunk (Mephitis mephi-tis), opossum (Didelphis virginiana), armadillo (Da-sypus novemcinctus), eastern cottontail (Sylvilagusfloridanus), black-tailed jackrabbit (Lepus californi-cus), eastern woodrat (Neotoma floridanus), hispid cot-ton rat (Sigmodon hispidus), hispid pocket mouse(Chaetodipus hispidus), Ord’s kangaroo rat (Dipodo-mys ordii), fulvous harvest mouse (Reithrodontomysfulvescens), deer mouse (Peromyscus maniculatus),white-footed mouse (Peromyscus leucopus), domesticcattle (Bos sp.), northern bobwhite, greater roadrunner(Geococcyx californianus), prickly pear fruit, mesquitebeans, and a variety of songbirds, reptiles, and insects.1Henke: Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas58 HENKETable 1. Percent of coyote stomachs (i.e., frequency of occurrence) that contained the diet item, analyzed from coyotes collected insouthern Texas during 1994–1997.Diet item1Collection dateMar 1994(n  200)Jul 1995(n  98)Oct 1997(n  42)Jan 1997(n  67)Total(n  407)RodentLagomorphInsectVegetationMisc. bird41.5232.00.08.03.09.214.359.237.87.19.511.945.228.611.941.834.30.00.09.030.526.018.916.05.9(Bobwhites) (3.0) (3.1) (2.4) (3.0) (2.9)LivestockMisc. reptileMisc. mammalWhite-tailed deer1.50.00.50.06.17.16.18.24.819.04.80.010.40.03.00.04.43.72.72.0EmptyMean no. of diet items/stomach15.51.010.21.614.31.513.41.113.81.21 Common diet items found in coyote stomachs consisted of Ord’s kangaroo rats, cotton rats, woodrats, hispid pocket mice, black-tailedjackrabbits, eastern cottontails, grasshoppers and beetles within the Families Locustidae and Carabidae, respectively, mesquite beans, pricklypear fruit, Texas persimmons, agarito barberries, acorns, livestock, northern bobwhites, roadrunners, sandhill cranes, ravens, skunks, arma-dillos, 6-lined racers, and bullsnakes.2 Proportion of stomachs that contained the diet item as calculated from the number of stomachs that contained the diet item/number ofstomachs examined.METHODSCoyotes were collected by aerial and ground hunt-ing during March 1994, July 1995, January 1997, andOctober 1997. Coyotes were field necropsied, theirstomachs excised and kept on wet ice until they couldbe frozen at23 C.In the laboratory, each stomach was thawed andthe contents were emptied into a shallow pan for ex-amination. Stomach samples were analyzed by boththe frequency of occurrence method (Andelt 1985) andthe percent occurrence method (Chamrad and Box1964). In short, frequency of occurrence was calculat-ed as the proportion of stomachs that contained a par-ticular food item. The overall frequency of occurrencecan sum to100% because coyote stomachs oftencontain multiple prey items. Percent occurrence wasdetermined using a 100-point frame (Chamrad andBox 1964, Johnson and Hansen 1977). Food itemsfrom each sample (one sample contents of one stom-ach) were spread onto the frame and 100 randompoints were selected. Each food item that lay on orclosest to each of the 100 random points was identi-fied. Reference samples of available foods from thestudy areas were used to identify individual fooditems. Hair was identified to species following Stains(1958) and seeds were identified according to Martinand Barkley (1961).Due to differential digestibility of food items, coy-ote food habits are reported by the percent occurrenceand frequency of occurrence methods. This is becausethe importance of common but highly digestible foods(e.g., grasshoppers) often are underestimated in thediet by percent occurrence method alone. Frequencyof occurrence data are expressed as the proportion ofcoyote stomachs that contained a particular food item.Data for percent occurrence is expressed as an aggre-gate percent due to stomachs of varying weights (Lit-vaitis et al. 1994). An analysis of seasonal effects oncoyote food habits was not performed because of po-tential confounding effects; seasonal coyote collectiondid not occur during the same year (i.e., year effects)and specimens were not consistently collected fromeach ranch each season (i.e., area effects).RESULTSFour hundred and seven coyote stomachs were an-alyzed, of which 56 were empty (Table 1). The numberof stomachs analyzed from each collection period was200, 98, 67, and 42 for March 1994, July 1995, Jan-uary 1997, and October 1997, respectively.Mammalian prey, insects, and vegetation com-prised nearly 96% of the diet of coyotes from southernTexas. Expressing the diet by the aggregate percentmethod, lagomorphs (26.6%) and rodents (26.2%)comprised the majority of the diet of coyotes, followedby insects (16.3%), vegetation (11.6%), white-taileddeer fawns (6.7%), livestock (6.3%), miscellaneousbirds (3.4%), miscellaneous mammals (1.8%), andmiscellaneous reptiles (1.1%). Of the miscellaneousbirds, northern bobwhites and their eggs comprisedonly 0.9% of the coyote diet by the aggregate percentmethod. Only 12 of the 407 coyote stomachs containednorthern bobwhite or their eggs (Table 1).Black-tailed jackrabbits and eastern cottontail rab-bits comprised the lagomorph category, while Ord’skangaroo rats, cotton rats, woodrats, and hispid pocketmice were the most common rodent species identified.Grasshoppers and beetles in the Families Locustidaeand Carabidae, respectively, were the common insectsfound in the stomachs. Mesquite beans, prickly pearfruit, Texas persimmon (Diospyros texana), agaritobarberry (Berberis trifoliolata), and acorns (Quercussp.) comprised the majority of plant material eaten bycoyotes. Livestock (i.e., cattle) remains as carrion incoyote stomachs could not be distinguished from live-killed animals. Bird species found in coyote stomachswere northern bobwhites, roadrunners, sandhill cranes2National Quail Symposium Proceedings, Vol. 5 [2002], Art. 759COYOTES AND QUAIL(Grus canadensis), and ravens (Corvus cryptoleucus).The miscellaneous mammal group consisted of skunkand armadillo, while the miscellaneous reptiles were6-lined racers (Cnemidophorus sexlineatus) and abullsnake (Pituophis melanoleucus).DISCUSSIONNorthern bobwhites were not a major prey item ofcoyotes in southern Texas. These findings are consis-tent with numerous other reports of coyote food habitsthroughout the United States. Evidence of bobwhitedepredation was found in 1.4% of 770 coyote stom-achs in Missouri (Korschgen 1957), 2.0% of 168 stom-achs in Arkansas (Gipson 1974), 0.2% by volume in514 scats from Texas (Meinzer et al. 1975), and 0.6%of 311 stomachs and scats from Mississippi and Ala-bama (Wooding et al. 1984). In other studies wherediet items were placed in broader categories than inthis paper, birds constituted only 1% of the coyote dietin 6,354 scats from southern Texas (Andelt et al.1987), 2.4% of the diet in 1,042 scats from California(Barrett 1983), 2.5% of the diet in 831 scats from Ida-ho (Johnson and Hansen 1979), and 2.0% of preyfound in 208 scats from South Dakota (MacCrackenand Uresk 1984).The obvious question is why the seemingly dis-parate results between Lehmann’s (1946) research andmore recent studies? I believe the answer was givenby Guthery (1995) who stated that Lehmann’s (1946)results were biased because of inappropriate statisticalprocedures. In addition, Lehmann (1946) reported re-sults from a small sample size and relied on circum-stantial evidence to determine the species of nest pred-ator. Herna´ndez et al. (1997) demonstrated that themo-dus operandi of nest predators is too similar betweenseveral species to confidently distinguish one predatorfrom another based only on nest debris and egg shellfragments.Often, predator control is suggested as a means toincrease production and survival of northern bob-whites (Lehmann 1984:190–196, Reynolds and Tapper1996, Rollins 1999). However, the results of this studyprovide evidence that such practices against coyoteswill not increase bobwhite populations. Although coy-otes may occasionally eat bobwhites or their eggs,there is no evidence that such levels of predation neg-atively influence the population dynamics of northernbobwhites.In fact, it is possible that coyotes may inadver-tently aid northern bobwhites by reducing the numbersof more serious quail predators. Removal of coyotescan cause a phenomenon known as mesopredator re-lease (Henke and Bryant 1999); an increase in theabundance of smaller-sized (i.e., meso) predators suchas raccoons, skunks, badgers (Taxidea taxus), grayfoxes (Urocyon cinereoargenteus), and bobcats (Lynxrufus) with the removal of a dominant predator. Henkeand Bryant (1999) demonstrated an increase in me-sopredator abundance after just 1 year of a seasonalcoyote removal program. In at least 1 instance meso-predators were considered more efficient nest preda-tors of northern bobwhites than coyotes (Herna´ndez etal. 1997). Sovada et al. (1995) reported that coyoteremoval led to a greater abundance of red foxes (Vul-pes vulpes), which resulted in a greater loss of water-fowl production in the Prairie Pothole region. The pos-sibility of a greater loss of bobwhite production to me-sopredators could exist in southern Texas with the im-plementation of coyote removal. Therefore the benefitof coyotes to bobwhites may actually outweigh theoccasional loss of birds to coyotes by depredation.ACKNOWLEDGMENTSI thank the Texas Department of Health and theTexas Wildlife Damage Management Services for per-sonnel to assist with coyote collections, and S. C. Far-ry, C. L. Kerr, and M. Perez for assistance in coyotecollection and necropsy. Thanks also are extended toP. Robertson, S. DeMaso, and W. Kuvlesky for com-ments on an earlier draft of this manuscript. This ispublication no. 02-104 of the Caesar Kleberg WildlifeResearch Institute.LITERATURE CITEDAndelt, W. F. 1985. Behavioral ecology of coyotes in south Tex-as. Wildlife Monographs 94.Andelt, W. F., J. G. Kie, F. F. Knowlton, and K. Cardwell. 1987.Variation in coyote diets associated with season and suc-cessional changes in vegetation. Journal of Wildlife Man-agement 51:273–277.Barrett, R. H. 1983. Food habits of coyotes,Canis latrans, ineastern Tehama County, California. California Fish andGame 69:184–196.Beasom, S. L. 1974. Intensive short-term predator removal as agame management tool. Transactions of the North AmericanWildlife and Natural Resources Conference 39:230–240.Bekoff, M. 1977. The coyote,Canis latrans. Mammalian Spe-cies 79:1–9.Brennan, L. A. 1991. How can we reverse the northern bobwhitepopulation decline? Wildlife Society Bulletin 19:544–555.Chamrad, A. D., and T. W. Box. 1964. A point frame for sam-pling rumen contents. Journal of Wildlife Management 28:473–477.Fulbright, T. E. 2001. Human-induced vegetation changes in theTamaulipan scrub of La Frontera. Pages 166–175in G. L.Webster and C. J. Bahre, eds. Changing plant life of LaFrontera. University of New Mexico Press, Albuquerque.Gipson, P. S. 1974. Food habits of coyotes in Arkansas. Journalof Wildlife Management 38:848–853.Guthery, F. S. 1995. Coyotes and upland gamebirds. Pages 104–107 in D. Rollins, C. Richardson, T. Blankenship, K. Canon,and S. E. Henke, eds. Coyotes in the southwest: a compen-dium of our knowledge. Texas Parks and Wildlife Depart-ment, Austin.Henke, S. E., and F. C. Bryant. 1999. Effect of coyote removalon the faunal community in western Texas. Journal of Wild-life Management 63:1066–1081.Hernández, F., D. Rollins, and R. Cantu. 1997. Evaluating evi-dence to identify ground-nest predators in west Texas. Wild-life Society Bulletin 25:826–831.Johnson, M. K., and R. M. Hansen. 1977. Comparison of pointframe and hand separation of coyote scats. Journal of Wild-life Management 41:319–320.Johnson, M. K., and R. M. Hansen. 1979. Coyote food habits3Henke: Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas60 HENKEon the Idaho National Engineering Laboratory. Journal ofWildlife Management 43:951–956.Korschgen, L. J. 1957. Food habits of the coyote in Missouri.Journal of Wildlife Management 21:424–435.Lehmann, V. W. 1946. Bobwhite quail reproduction in south-western Texas. 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Journal ofRange Management 28:22–27.Reynolds, J. C., and S. C. Tapper. 1996. Control of mammalianpredators in game management and conservation. Mam-malian Review 26:127–156.Rollins, D. 1999. Is there a place for predator control in quailmanagement? Pages 45–48in K. A. Cearley, editor. Pre-serving Texas’ quail heritage into the 21st century. TexasAgriculture Extension Service, Abilene, Texas.Rollins, D., and J. P. Carroll. 2001. Impacts of predation onquail. Pages 84–101in T. F. Ginnett and S. E. Henke, eds.The role of predator control as a tool in game management.Texas Agricultural Extension Service, San Angelo, Texas.Sovada, M. A., A. B. Sargeant, and J. W. Grier. 1995. Differ-ential effects of coyotes and red foxes on duck nest success.Journal of Wildlife Management 59:1–9.Sperry, C. C. 1941. Food habits of the coyote. United StatesDepartment of Interior, Fish & Wildlife Service ResearchBulletin 4, Washington, D. C.Stains, H. J. 1958. Field key to guard hair of middle westernfurbearers. Journal of Wildlife Management 22:95–97.Wallace M. C. 2001. Turkey, quail, and predators in the RollingPlains, Texas. Pages 139–143in T. F. Ginnett and S. E.Henke, eds. The role of predator control as a tool in gamemanagement. Texas Agricultural Extension Service, SanAngelo, Texas.Wooding, J. B., E. P. Hill, and P. W. Sumner. 1984. Coyote foodhabits in Mississippi and Alabama. Proceedings of theSoutheastern Association of Fish and Wildlife Agencies 38:126–133.4National Quail Symposium Proceedings, Vol. 5 [2002], Art. 7

Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas

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Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas

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