148 SHORT COMMUNICATIONS VOL. 36, NO. 2 LITERATURE CITED tats of Chile, Spain, and California: a comparativeap- proach. Am. Midl. Nat. 107:151-162. AGUIRRE,L.E ANDS. ANDERSON.1997. Clave de campo MARTI,C.D., E. KORPIMAKI,AND EM. Jpacslc.1993. Trophic para la identificaci6n de los murci61agosen Bolivia. structureof raptor communities:a three-continentcom- Serie Zoologia No. 5, Instituto de Ecologia,La Paz. parisonand synthesis.Curz. Ornithol. 10:47-137. ANDERSON,S. 1997. Mammals of Bolivia:taxonomy and MIES, R., A. KURTA,AND D.G. IgJNG.1996. Eptesicusfun- distribution. Bull. Am. Mus. Nat. Hist. 231:1-652. nalis.Mamm. Species526:1-7. BRACE,R.C., J. HORNBUCKI.E,AND J.W. PEARCE-HIGGINS. MOTrA-Jt)NIOR,J.C. ANDV.A. TADDEI.1992. Batsas prey 1997. The avifaunaof the Beni BiologicalStation, Bo- of the StygianOwl in southeasternBrazil. J. RaptorRes livia. Bird Conserv. lnt. 7:117-159. 26:259-260. EISENBERG,J.E ANDK.H. REDVORD.1999. Mammals of the MUSSER,G.G., M.D. CASTLETON,E.M. 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SmithsonianInstitution, Washing- Mamm. Species39:1-3. ton, DC U.S.A. JAKSIC,EM., R.L. SEro,AND C.M. HEPmERA.1982. Preda- Received 23 December 2000; accepted 22 November tion of Barn Owl (Tyt0 alba) in mediterraneanhabi- 2001 j RaptorRes. 36(2):148-152 ¸ 2002 The Raptor Research Foundation, Inc. FOOD OF THE LESSERKESTREL (FALCO NAUMANNI) IN ITS WINTER QUARTERSIN SOUTHAFRICA GRZEGORZKOPIJ 1 Departmentof Biology,National Universityof Lesotho,P.O. Roma180, Lesotho KEYWORDS: LesserKestrel; Falco naumanni; winterquar- (Siegfriedand Skead 1971, del Hoyo et al. 1992). A dras- ters;South Africa; diet;,Solifugae. tic decline in wintering LesserKestrels was also noted in this province,where ca. 74 000 birds were recorded dur- The LesserKestrel (Falco naumanni) has undergonea ing the australsummer of 1966--67(Siegfried and Skead drastic decline in this century in its breeding range in 1971) and only 33900 during the austral summer of the southern Palearctic and is classified as RARE in the 1992-93 (Roosand Roos1986, Colahah 1993). Preycon- RedData Book(del Hoyo et al. 1992, Tucker and Heath taminated by pesticidesand the destruction of natural 1994). At present, 6000-10 000 breeding pairs occur in habitatsin the LesserKestrel's breeding range have been Europe (Gonzalezand Merino 1990). Recently,the great- suggestedas the main factorsresponsible for the decline est density of breeding Lesser Kestrelswas reported in (del Hoyo et al. 1992, Tucker and Heath 1994). Spain,where an estimated20 000-50 000 breeding pairs Food availabilityis one of the most important ultimate •n 1980 had fallen to 4200-5100 by 1990 (Tucker and factorscontrolling any avian populationand information Heath 1994). on the diet of a declining species,such as the Lesser The LesserKestrel is migratoryand most individuals Kestrel, is therefore vital for conservation. Summer diet winter in the grasslandsof the Free Statein SouthAfrica of the LesserKestrel has been investigatedquantitatively in Spain, France, and Austria (Cramp and Simmons 1980, Bijlsma et al. 1988). The diet in winter has been Present address: R.aczka 13, 49-137, Korfantow, Poland. examined through the analysisof stomachcontents (An- JUNE 2002 SHORTCOMMUNICATIONS 149 derson et al. 1999, Kok et al. 2000). In this paper, I pre- thopteransand beetleswere alsoan important component, sent data on the Lesser Kestrel diet as determined by togetherforming 27.5% of the totalnumber of preyitems analysisof pelletscollected in SouthAfrican grasslands. identifiedand 44.4%of the totalwet biomass(Table 1, Fig 1). Orthoptera were mainly representedby grasshoppers METHODS (Orthoptera:Acrididae), while beetlesmainly by scarabae- The food of the LesserKestrel was determined by anal- ids.Other arthropodgroups, such as earwigs, termites, cock- ysis of pellets. Most pellets were collected between No- roaches(Blattodea), dragonflies, and scolopendrasconsti- vember1997 and February1998 from a traditionalroost- tuted supplementaryfood (Table 1). Only a few vertebrate lng site in a stand of large eucalyptus(Eucalyptus sp.) in itemsrepresented by smallmammals were found (Table 1) Oosteinde, Bloemfontein, South Africa (29ø10'S, Three pelletscontained small stones. 26ø15'E). About 2000 Lesser Kestrels roosted there from late October1997 to earlyMarch 1998.A few pelletswere Sun spiders were especially numerous in the Lesser also collected in four other traditional roosting sites (in Kestrel'sdiet in November-December, being recorded in large eucalyptus)in the Free State:at Winburg (27ø01'S, each pellet examined (Fig. la), and formed over 80% of 28ø30'E),70 km NE of Bloemfontein(25 pelletscollected the total wet biomassconsumed (Fig. lc) and over 70% on 22 November 1997), at Reddersburg (29ø39'S, of total prey items consumed (Fig. lb). Out of 105 and 26ø10'E),40 km S of Bloemfontein(100 pelletscollected 275 pellets selectedrandomly from November-Decem- on 26January1998), at Edenburg(29ø43'S, 25ø55'E), 15 ber (100% of which containedsun spiders) and January- km SW of Edenburg (74 pelletscollected on 5 January February (49% containedsun spiders),respectively, the 1998), and at Trompsburg(30ø02'S, 25ø43'E), 23 km SW mean number of sun spidersper pellet decreasedsignif- of Edenburg (85 pellets collected on 5 January 1998). icantly (t = 4.10, df = 26, P = 0.005) from November- The natural vegetation around Winburg is represented by the Cymbopogon-ThemedaVeld, while the False Upper December (i = 8.87, SD = 25.34, range = 1-17, N = Karoo is the natural vegetationat the other sites.Most of 105) to January-February(i = 1.40, SD = 8.68, range = the natural vegetation around all four sites has been, 0-10, N = 275). however, converted into cultivated fields. The quantityof sunspiders consumed by the LesserKes- The rainfall during November-December1997 was trel in Bloemfontein,as reflected in the randomly-selected much lower (50 mm), while during January-February pellets containing sun spiders (Fig. 3), decreasedas the 1998 much higher (420 mm) than long-term (40 yr) av- winteringseason progressed (X 2 = 98.79, P < 0.01, df = erage for theseperiods (ca. 140 mm for November-De- 3). In contrast,the proportion of pelletscontaining beetles cember and ca. 170 mm forJanuary-February). significantlyincreased (X 2 = 47.49,P < 0.01, df = 3), and Only fresh and compact pellets were collected in the middle and at the end of each month of the study.Each Orthopterans were more frequently found in pellets •n pellet was broken apart by hand and remains of prey January-Februarythan in November-December(X • = items were identified mainly to the level of order. The 43.22, P • 0.01, df = 3; Fig. la). Similarly,the frequency following prey remains were isolated for identification: with which other prey, such as earwigs, termites, small chelicerae of sun spiders (Solifugae), exoskeletons,jaws mammals etc., were taken increased toward the end of the and elytrae of orthopterans (Orthoptera) and beetles winteringseason (X • = 11.86, P • 0.01, df = 3; Fig. la) (Coleoptera), cerci of earwigs(Dermaptera), headsand Sun spiderswere equallycommon at other localitiesin wings of termites (Isoptera), and hair of small mammals the Free State (Fig. 2), being found in almostevery pellet (Micromammalia). collected(X • = 3.49, P > 0.05, df = 7). The contribuuon Frequencyof occurrencewas calculated as the propor- tion of the total number of pellets examined containing of orthopteranprey decreasedsouthward, i.e., from wetter a given taxon. Estimation of prey number and their wet to drier areas (X• = 23.28, P • 0.005, df = 7), while the biomassin the pellets was based on the following as- contributionof beetlesand other preygroups to the falcon's sumptionsand calculations(wet biomassof prey X mean diet (Fig. 3) wasmarkedly different from site to site (X2 = number of prey per pellet): sun spiders,1.4 g X 8.5 in 112.6, P < 0.001, df = 7 and X• = 21.86, P < 0.005, df = November-December, 1.4 g X 2.5 in January-February; 7 for beetlesand other preygroups, respectively). orthopterans1.4 g X 2; crickets(Orthoptera: Gryllidae), 1.4 g X 1; beetles,0.7 g X 2; scarabaeids(Coleoptera: DISCUSSION Scarabaeidae),0.7 g X 2; ground beetles (Coleoptera: Carabidae), 0.3 g X 2; tenebrionids(Coleoptera: Tene- During the breeding season,beetles and grasshoppers brionidae), 0.3 g X 2; termites, 0.1 g X 10; earwigs,0.1 constitute the bulk of the Lesser Kestrel diet, supple- g X 2; dragonflies (Odonata), 1.0 g X 1; scolopendras mented by a low frequency of large prey, such as small (Chilopoda: Scolopendromorpha),2.0 g X 1; small in- mammals, lizards (Sauria), bush crickets (Orthoptera. sectivorousmammals (Mammalia: Insectivora), 10 g X 1; Tettigonidae), and mole crickets (Orthoptera: Gryllotal- small mammals, 20 g X 1. pidae) (Cramp and Simmons1980, Bijlsmaet al. 1988). RESULTS In South Africa, these larger prey groups are replaced mainly by smaller sun spidersand termites,while verte- A total of 2050 pelletswas collectedfrom November brate prey are taken only occasionally(Anderson et al. 1997-February1998.