]. RaptorRes. 30(3):165-168 ¸ 1996 The Raptor ResearchFoundation, Inc. NUMBERS AND DISTRIBUTION OF RED-FOOTED FALCON (FALCO VESPERTINU5) NESTS IN VOIVODINA (NORTHERN SERBIA) JENOJ. PURGER Departmentof Ecologyand Zoogeography,Janus Pannonius University, 7601 Pdcs,IJjziscig ,itja 6, Hungary K•Y WO}•DS: red-footedfalcon; Falco vespertinus;Voivodi- and support willows (Salix spp.) and poplar (Populus spp.) forestsand meadows.Approximately 10% of Voiv- odina has saline soilswhich are used for pasturesand, in The breeding range of red-looted falcon (Falcovesper- some places,fishponds. t•nus) in the Palearctic extends across the broad band of The red-looted falcon censuswas performed from 28 steppe, foreststeppeand cultivated lands in the north April-14 July in 1990, and from 27 April-22 July in 1991. temperate zone (Cade 1982). The western limit of this In 1990, surveyswere conducted for 28 d, while in the speciesextends to the westernborder of Hungary in Cen- second year the survey took 33 d. Srem, Bachka, and tral Europe (Keve and Szijj 1957, Lohmann 1962, Glutz Banat were surveyedon 7, 18 and 36 d, respectively.In et al. 1971, Cramp and Simmons 1980). Although a rel- both years,an observerand I drove all the main roads in atively large red-looted falcon population occurs in the Voivodina, usually 200-400 km per day, for a total of CarpathianBasin (Keveand Szijj 1957,Glutz et al. 1971, >20 000 km. Over a 3-d period at the end of April, and Cramp and Simmons 1980), very little is known about over 16 d in May in both surveyyears, I also searchedfor their number and breeding distributionin the northern rook colonies and recorded any red-looted falcons ob- provinceof Serbia,Voivodina (Antal et al. 1971, Pelle et served. al 1977). Horv•th (1955) observed red-footed falcons laying Based on limited information, Vasi• et al. (1985) made eggsin the secondhalf of May and concludedthat nests a preliminary estimate of 80 pairs of red-looted falcons became occupied 2-3 weeksbefore egg laying. To deter- m Voivodina.However, this preliminary work did not pro- mine clutch and brood sizes of red-looted falcons, nest vide a clear picture of the distribution of nesting areas. trees were climbed twice in June and July. Only those Herein, I provide the results of a recent survey of the nestscontaining at leastone egg during the first nestvisit numbers and distribution of red-looted falcon nests in were included in nest size estimates. When nests were the area. impossible to climb, they were checked twice from the Voivodina is a mostly flat region in northern Serbia ground to make certain that the female wasin the same that lies in the southeasternpart of the CarpathianBasin. nest and to count nestlingsstanding on the edge of the It is divided by the Danube, Tisa, and Sava Rivers into nest. three areas:Bachka, Banat, and Srem (Fig. 1). The Bach- To make the census more complete, information on ka region (8956 km2) lies betweenthe Tisaand Danube rook colonies and locations of red-looted falcon nests was Riversand borderswith Hungary in the north. The Banat obtained from the Associationfor Protection and Study region (8886 km2) is north of the DanubeRiver and east of Birds of Voivodina. This was originally reported by A. of the Tisa River and borderswith Hungary and Roma- Zsulyevits,M. Devi• and J. Raiajski (Table 1). nia. The Srem region (3838 km•) lies betweenthe Dan- I found 308 pairs and 124 pairs of red-looted falcons ube and Sava Rivers and borders with Croatia. The area in Voivodina in 1990 and 1991, respectively (Table 1). ranges from 70-200 m above sea level and two moun- Breeding pairs were found only in Bachka and in Banat truns, the Fru•ka Gora (539 m) in Srem and the Vr•ac (Fig. 1). In 1990 four, while in 1991, five pairs nested in Mountains (641 m) in southeastern Banat rise above the northwestern and southeastern Bachka between the Dan- large plain. They support deciduousforests dominated ube and Tisa Rivers. In all cases, red-looted falcons nest- by oak (Quercusspp.), linden (2t•liaspp.), and hornbeam ed in isolatedmagpie (Picapica) or hooded crow (Cor•us (Carpinus spp.). The lower slopes have mostly been coronecornix) nests. cleared and are used for pastures, vineyards and or- In Banat, 304 pairs of red-looted falcons were found chards.Voivodina is largely agriculturaland only 5.4% is in 1990, while only 119 pairswere recorded in 1991. Most forested. The most common soil type is chernozem, a nestswere either along the Tisa River or in the foothills blacksoil, covering 60% of the arableland. It is extreme- of the Vriac Mountains (Fig. 1). In 1990, red-looted fal- ly fertile and mainly used for cultivation of cropssuch as cons nested in 15 separatelocations. With the exception wheat, maize, sugar beets,sunflowers, and soya.Industri- of three isolated pairs found in old magpie nests (in the al crops, fodder crops and vegetablesare also cultivated vicinityof the villagesof BoYar,Dobrica and Konak), red- on the black marsh soil. Alluvial soilsoccur in river valleys looted falconsnested in rook (Corvusfrug'ilegus)colonies. 165 166 SHORT COMMUNICATIONS VOL. 30, No. 3 C D HUNGARY Falco vespertinus -Nesting location N Voivodina UTM 10xlOkm R C 4 D s E Figure 1. Breedingdistribution of red-footedfalcon in Voivodinaduring 1990 and 1991 basedon the bird censusdata. Five large colonies were used including one near the (Udvardy 1969). The spring of 1991 wascooler and wet- village of Jazovowhere 147 pairs of red-footed falcons ter than 1990, which delayed nesting of rooks. Thus, nested. In 1991, 19 sites were used in Banat. At 9 sites, when red-footed falcons arrived at the end of April to 11 pairs nested in abandoned magpie or hooded crow breed, rooks were still occupying nests and they were nests.At the other 10 sites, 108 pairs nested in rook col- forced to find alternative nest sites.It is possiblethat onies. The four largest colonies were near Jazovo (29 some of the falcons may have gone further north, but pairs), Melenci (27 pairs),Vlajkovac (16 pairs), and Tor- the rest may have used abandoned magpie and hooded da (14 pairs) (Table 1). crow nests or tried to occupy empty nests inside rook Birds of prey that breed in coloniestend to nestin the coloniesthat were still active.Usually, red-footed falcons same location year after year (Newton 1979). In this that nest in colonies are more reproductivelysuccessful study, red-footed falcons also reused colonies but the than solitarynesters (Haraszthy and Bagyura1993). Un- numbers of breeding pairs decreasedfrom 308 pairs in favorableweather conditionsmay, therefore, lower repro- 1990 to only 124 pairsin 1991. There are severalpossible ductive successof red-footed falconsby forcing them to reasons for the difference between the results of the two nest in less suitable, isolated magpie and hooded crow census years. The census in Vojvodina was conducted nests. near the peripheryof the speciesdistribution. Peripheral Raptors may also become concentrated in the breed- populations tend to react more sensitivelyto environ- ing seasonin areaswith abundant food (Newton 1979). mental changes than do more central populations Voivodina is predominantly agricultural and grasslands SEPTEMBER 1996 SHORT COMMUNICATIONS 167 Table 1. Number of breeding pairs of red-footed falcon regi6n este de Banat, mientras que s61o4-5 parejas ni- found in Voivodina during 1990 and 1991. dificaron en Bachka,ninguna nidific6 en Srem. Falcoves- pertinns ocup6 nidos de colonias de Corvusfrugilegus UTM LOCALITY 1990 1991 (>90% de las veces),Pica pica y Corvuscorone cornix. En 1990, las tres coloniasmils grandesestaban en las vecin- Bachka dadesde lasvillas de Jazovo,Melenci y Vlajkovac,las que CR57 Lenija, 6 km northeastof Sombor 1 2 tertian 147, 46 y 42 parejas reproductivas,respectiva- (A. Zsulyevits) mente. Las mismascolonias soportaron solamente 29, 27 Mil•i•, 8 km northeast of Sombor 1 -- y 16 parejasen 1991. He atribuido esta diferencia al frio (A. Zsulyevits) y 11uviaprimaveral ocurridas en 1991, las que provocaron CR58 Ran•evo, 14 km north of Sombor -- 2 un retardo en la nidificaci6n de C.frugilegus, 1o que prev- (A. Zsulyevits) ino la ocupaci6n de los nidos por parte de los halcones. CR68 5 km southwest of Aleksa ganti• -- 1 La falta de insectos-presaprobablemente tambi•n con- DR12 2 km west of Gospodjinci 1 -- tribuy6 a la declinaci6n en el nfimero de parejas hidifi- DR13 8 km northeast of Ternerin l -- cantes de halcones. [Traducci6n de Ivan Lazo] Banat DR44 7 km north of Melenci 3 -- ACKNOWLEDGMENTS 5 km northeast of Melenci 46 27 I would like to thank M. Devil, T. Karanovi•, R. Kor- DR45 Slano kopovo, 9 km east of Novi -- 1 minyos, S. Lukics,J. Ra•ajskiand A. Zsulyevitsfor collab- Be•ej oration, J. Majer and J. T6r6k for helpful comments on 6 km southwest of Ba•aid -- 2 a draft of the paper.Also, I am grateful to J. Hunyady for DR46 5 km west of BoYar 1 -- translation. Finally I thank J.C. Bednarz, G.R. Bortolotti 6 km southwest of Novo Milo•evo 6 -- and J. Bustamantewho gave useful suggestionson the DR47 1 km eastof Idjo• -- 2 text. DR48 2 km southeastof Jazovo 147 29 LITERATURE CITED DR49 2 km southwest of Vrbica -- 1 2 km west of Banatski Mono•tor -- 1 ANTAL,L., J. FERNBACH,J. MIKUSKA,[. PEELEAND L. SZLIV- 1 km west of Banatski Mono•tor -- 1 RA. 1971. Namenverzeichnisder Vtgel der Antono- DR53 3 km northwest of Jankov Most 1 2 men ProvinzVojvodina. Earns 23:73-127. DR54 2 km south of Torda 20 14 CA•E, TJ. 1982. The falcons of the world. Collins, Lon- 4 km southwest of Torda 12 3 don, U.K.