HABITAT SELECTION BY THE AMERICAN (Falcosparverious) AND RED-TAILED HAWK (Buteojamaicensis)WINTERING IN MADISON COUNTY, KENTUCKY

NANCYj. SFERRA

ABSTRACT- Habitat selection by the AmericanKestrel (Falco sparverius) and Red-tailed Hawk (Buteo jamaicensis) in MadisonCounty, Kentucky, was determined for the winterof 1980-81.Results showed that there wassignificant non-randomuse of 6 habitattypes (: X2 = 629.5,P • 0.05,d.f. = 5; Red-tailedHawks: X 2 = 124.8,P • 0.05,d.f. = 5) withold field sitesbeing used most frequently by both species. The American Kestrel (Falcosparverius) and were locatedby meansof an automobileroad count Red-tailed Hawk (Buteojamaicensis) are the most (Craigheadand Craighead 1956) covering secondary roads of the numerous diurnal raptors wintering in Madison Icounty. The countroutes were chosen so that each of thephysiog- raphicregions in the countywere represented. One roadcount County(Sferra 1984). Mengel (1965) reported that, wasrun weeklyfrom lateDecember 1980 to March 1981for a total in Kentucky,kestrels preferred open areas. Along of 10 counts. Each covered the same 235 km and were not run highwaysin West Virginia, kestrelsmost often whenvisibility was hampered by snow,fog, or rain. A driver/ huntedin pasturelands,or openareas planted with observerand passenger/observer were present during each cen- sus.Routes were driven at speedsbetween 32-48 kph, and all Lespedezaspp. (Ferris 1974). However,near high- raptor sightingson both sidesof the road were recorded.The waysin the Texas panhandle,kestrels frequented maximumdistance of sightingson each side of the road was wooded areas (Allan and Sime 1943). approximately440 m. Red-tailed Hawks were most commonly as- Habitatsdirectly beneath raptors in flight,and areas overlooked sociated with woodlots in Iowa and the Texas byperched birds formed the basis for determining species-specific habitat utilization. Six habitat categorieswere distin- panhandle (Allan and Sime 1943; Weller 1964). guished:pastureland (both grazed pasture and mowed Petersen(1979) reported that Red-tailedHawks hayfields),cropland, urban areas, old fields, woodlots and plowed seldomused internal portions of woodlots,sup- fields.Actual habitat use was tested against their relative occurr- portingSchnell's (1968) observation that the species ence.Proportion of occurrencewas quantified from randomly selectedaerial photographsrepresenting 10% of the entire preferredperching at woodlotedges. In Michigan, county. open areas were heavily utilized (Craigheadand Craighead1956), lone trees being favored as perch RESULTS AND DISCUSSION sites(Chamberlain 1974). The six habitattypes occurred in the following High winterdensities of theseraptors in Madison proportions:57% pasturelandand hayfields,33% County (Sferra 1984) may result from the amount woodlots,3% cropland, 3% urban areas, 2% old of openhabitat available for hunting,as well as the fields and 2% plowed fields. Kestrelsand Red- presenceof adjacent,heterogeneous edge habitat. tailed Hawksutilized certain habitats to a greater Many open areas are bordered by fencerowsof extent than that predictedby their relativeavaila- trees or are bisectedby power lines, providing bility.Chi-square (X 2) testsshowed significant non- perching sitesfrom which hawks can search for random habitat use by kestrelsand Red-tailed prey. The purposeof the presentstudy was to de- Hawkswintering in MadisonCounty (Table 1). terminethe relativeextent to whichwintering kes- trels and Red-tailed Hawks frequented various habitatsfound in MadisonCounty. Table 1. Resultsof Chi-square(X 2) analysisof habitat selection and utilization based on habitat av- STUDY AREA AND METHODS ailabilityin Madisoncounty. MadisonCounty encompasses parts of 4 physiographicregions in centralKentucky: the Hillsof theBluegrass, the Outer Blueg- rass, the Knobs Section of the Cumberland Plateau, and the SPECIES X2 Mountains(Soil Conservation Service 1973). Terrain ranges from rolling,upland plains to long,narrow ridge tops separated by steepvalleys with the maximumrelief being 335 m (Jillson1928). American Kcstrcl õ29.5 a MadisonCounty is composed predominantly of pasturelandand Red-tailed Hawk 124.8 a hayfieldswith foreststands being confined mainly to streammar- gins,field edges,and ruggedregions of the CumberlandPlateau and Mountains. ap < 0.05; d.f. = 5

148 RAPTORRESEARCH 18(4): 148-150 WINTER 1984 WINTER HABITAT SELECTION IN KENTUCKY 149

Table 2. Total number of AmericanKestrel and Red-tailedHawk sightingsand % deviationfrom expectedChi- squarevalues for their occurrencein eachof 6 habitattypes. A positivesign indicates habitat use greater than expectedand a negativesign indicates use less than expected.

AMERICAN KESTRELS RED-TAILED HAWK

HABITAT N % DEVIATION N % DEVIATION

Pastureland 276 + 38 117 + 28 Old Field 66 + 790 21 + 525 Cropland 15 + 76 1 - 59 Plowed Fields 5 - 31 1 - 70 Woodlots 3 - 98 28 - 65 Urban Areas 0 - 100 0 - 100

Kestrelshabitat use was as follows: pastureland were frequentedless than expected(Table 2). The 76.9%,old field 18.4%,cropland (consisting mainly majority of Red-tailed Hawks associatedwith of corn stubble)4.2%, plowed field 1.4%, woodlots woodlotswere perched along marginsoverlooking 0.8% and urban areas 0%. Percent deviations from openareas. Similarly, Petersen (1979), using a road expectedvalues of the chi-squaretest showedthat count in Wisconsin,found that internal portionsof kestrels utilized woodlots and urban areas less, and woodlots were seldom used. all other habitatsmore than expected.Selection of Of all habitat types,old field site use by hawks old fields wasmost pronounced(Table 2). deviatedthe most from the expectedvalues. Selec- The nature and distributionof perchingsites in a tion for old field sitesby kestrels,and to a lesser givensurveyed area probablyintroduced bias into degree by Red-tailed Hawks, may have been in- road count data. In the Texas panhandle, for in- duced by higher prey populations, specifically stance,frequent utilizationof woodlotsby kestrels Meadow (Microtuspennsylvanicus). Austing (Allan and Sime 1943) could have been directly (1964) found Meadow to be staple prey for related to lack of perchingsites in open habitat. In Red-tailed Hawks during winter months, and vole MadisonCounty, the majorityof kestrelswere seen populationdensity has been suggested as the major perchingon utilitylines, many of whichrun parallel factordetermining hawk distribution (Bart 1977). to the census route. On the other hand, birds hid- Kestrelsalso depend heavilyupon Meadow Voles den behind trees, buildings and signs.may have during winter (Craighead and Craighead 1956). In resulted in low utilization estimates for woodlot and Madison County, matted vegetationused by voles urban area use. for runways will not accumulateon intensively Winter habitat separationby sexeshas been re- grazedpastureland and mowedhayfields, resulting ported as common among kestrels in Texas, in decreasedpopulation density. Old field sites, California, Arizona, (Mills 1976; Koplin basedon presumedprey density,have the greatest 1973) and Georgia(Stinson et al. 1981). Chi-square potentialfor supportinglarge numbersof winter- test showedmale kestrelswere significantlymore ing kestrelsand Red-tailed Hawks. numerous than females (58% males, P (0.05). Acknowledgments However, sex-specificdifferences in habitat were not significantin MadisonCounty (P (0.05). Specialthanks are extended to thosewho helped in obtaining field data: R. Altman, G. BareIs, P. Mastrangelo,G. Murphy, J. Habitat selectionby Red-tailed Hawks was as Schafer,C. Schuler,T. Towles,and especiallyJ. Colburn. follows:pastureland 69.9%, woodlots16.7%, old field 12.5%, cropland 0.6%, plowed fields and LITERATURE CITED urban areas0%. Use of pasturelandand old field ALLAN, D.F. AND P.R. SIME. 1943. A hawk census on siteswas greater than expected;all other habitats Texas panhandlehighways. Wilson Bull. 55:29-39. 150 NANCYJ.SFERRA VOL.18, NO. 4

AUSTING, G.F. 1964. The world of the Red-tailed Hawk. SCHNELL,G.D. 1968. Differentialhabitat utilization by J.B. LippincottCo., Philadelphia.128 pp. winteringRough-legged and Red-tailedHawks. Con- BART,J. 1977. Winter distributionof Red-tailedHawks dor 70:373-377. in State. Wilson Bull. 89:623-625. SFERRA,N.J. 1984. Populationdensities of diurnalrap- CHAMBERLAIN,M.L. 1974. Fall huntingbehavior of the torswintering in MadisonCounty, Kentucky. Trans. Red-tailedHawk (Buteojamaicensis)in Central Michi- Ky. Acad. Sci. 45 (3-4):128-131. gan.Jack-pine Warbler 52: 2-9. SOiLCONSERVATION SERVICE. 1973. Soilsurvey of Made- CRAIGHEAD,j.j. ANDF.C. CRAIGHEAD,JR. 1956. Hawks, sonCounty, Kentucky. U.S.D.A. and Ky. Agri. Exp. owlsand wildlife.Stackpole, Harrisburg, Pa. 443 pp. Sta.,Lexington, Ky. FERRIS,C.R. 1974. Effectsof highwayson Red-tailed STINSON,c.n., D.L. CRAWFORDAND J. LAUTH- Hawks and Sparrow Hawks. M.S. Thesis. West Va. NER. 1981. Sex differences in winter habitat of Univ., Morgantown,W. Va. AmericanKestrels in Georgia.J.Field Ornith. 52:29-35. JILLSON,W.R. 1928. The geologyand mineral resources TELLER,M.W. 1964. Habitatutilization of twospecies of of Kentucky.Ky. Geol.Survey, Frankfort, Ky. Butcoswintering in central Iowa. Iowa Life KOPLIN,J.R. 1973. Differentialhabitat use by sexesof 34:58-62. AmericanKestrels wintering in Northern California. RaptorRes. 7:39-42. MENGEL,R.M. 1965. The birds of Kentucky.Ornithol. Dept.of Biol. Sci.,Eastern Ky. Univ.,Richmond, Ky. 40475. Mono. No. 3, Am. Ornithol. Union, Lawrence, Kansas. Presentaddress: Dept. of Zoology,Mich. StateUniv., E. Lans- MILLS, G.S. 1976. American Kestrel sex ratios and ing, Mich. 48824. habitat separation.Auk 93:740-748. PETERSEN,L. 1979. Ecologyof the Received15 July 1984;Accepted 30 January 1985 and Red-tailed Hawk in southeastern Wisconsin. Wisc. Dept. Nat. Res. Tech.Bull. No. 111, Madison, Wisc. 63 PP-