Journal of A nimal Ecology (1981), 50, 269-281

PREDATION UPON THE EUROPEAN RABBIT (ORYCTOLAGUS CUNICULUS) IN MEDITERRANEAN HABITATS OF CHILE AND SPAIN: A COMPARATIVE ANALYSIS BY

FABIAN M. JAKSIC

AND

RAMON C. SORIGUER

Museum of V ertebrate Zoology, University of California, Berkeley, CA 94720. U.S.A . and Estacion Biologica de Doñana, Sevilla 12. Spain Go to contents

SUMMARY

(1) The European Rabbit (Oryctolagus cuniculus) is a native of the mediterranean habitats of Spain, and was recently introduced to ecologically similar habitats in central Chile. (2) A survey of the quantitative information on body sizes of predators and on the importance of rabbits as prey in both southern Spain and central Chile was made. Patterns of habitat utilization by rabbits in the two areas were also compared. (3) Rabbits contribute on the average 20 . 6% of the vertebrate prey of twenty-nine species of Spanish predators: the figure is 2 . 0% in the diet of sixteen species of Chilean predators. The statistical distribution of body sizes of predators in southern Spain is not significantly different from that of predators in central Chile. The curve of habitat utilization by rabbits in central Chile is skewed toward low values of shrub cover, and that in southern Spain toward higher values of shrub cover. (4) The low consumption of rabbits by Chilean predators is associated with higher densities of native prey, relative to southern Spain. This might render more profitable for Chilean predators hunting for native prey than for introduced rabbits. INTRODUCTION The European rabbit (Oryctolagus cuniculus L.) is a native of the Mediterranean Basin which probably evolved on the Iberian Peninsula (Zeuner 1963; Layne 1967). It is presently distributed through most of Europe and the British Isles and has been introduced into Australia and New Zealand (Corbet 1978). This species was also introduced into Chile in the mid-18th century (Housse 1953) but was not recorded in central Chile as late as 1940 (Osgood 1943). By 1960 it was locally abundant in Malleco Province (Greer 1965) and in 1968 was considered to be a serious agricultural pest throughout central Chile (Pefaur et al. 1968; see also Pine. Miller & Schamberger 1979). Recently, it has crossed the Argentinian border. invading Neuquen Province (Howard & Amaya 1975). Numerous ecological studies on introduced European rabbits have been conducted in Australia (see Myers 1970; Wheeler & King 1980, and references therein) and New Zealand (see Wodzicki 1950: Gibb. Ward & Ward 1978. and references therein) but little attention was devoted to their ecology in native habitats until very recently (Pages 1977: De1ibes 1980: Rogers 1979. 1980: Soriguer 1979; Soriguer & Rogers 1980; Rogers & Myers 1979). Since its introduction to central Chile. the European rabbit has effected a 00 2 1-8 7901 8 1/0200-02 69$02.00 c, 1981 Blackwell Scientific Publications 269

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pronounced change in the spatial distribution of native herbs (Jaksic & Fuentes 1980). probably enhancing the success of introduced weeds. These rabbits are also causing considerable mortality among native shrub seedlings, which probably prevents the normal renewal of the native chaparral (E. R. Fuentes & F. M. Jaksic unpublished). These deleterious effects seem to be directly related to a marked change in the behaviour of the European rabbit in central Chile. In Spain. rabbits restrict their foraging activities to areas beneath or near shrubs (Rogers 1974; S. D. Busack, pers. comm.) but in central Chile they feed in open spaces between shrubs-independently of the distance between neighbouring shrubs-(Jaksic. Fuentes & Yanez 1979a. 1979b). Foraging under. or close to, cover is associated with the strong predation pressure upon rabbits in Spain (Delibes 1980; Soriguer 1979; Soriguer & Rogers 1980). while foraging in the open may be a manifestation of predation pressure which is weak or absent. This would allow rabbits in central Chile to forage safely in the open spaces between shrubs, where herbs are more abundant (Montenegro, Rivera & Bas 1978: Jaksic & Montenegro 1979). rather than closer to shrubs where the numerous native rodents concentrate their foraging activities (Jaksic. Fuentes & Yanez 1979a.b). Since both areas are mediterranean-type ecosystems (di Castri & Mooney 1973) characterized by similar physiognomy. climate. and resources, where plant and animal communities usually exhibit ecological convergence (Mooney 1977; Thrower & Bradbury 1977). a comparison between these two areas should be quite meaningful. This paper quantitatively documents the importance of rabbits as prey in the mediterranean habitats of central Chile and southern Spain to test the hypothesis that the behavioural change shown by the rabbits of central Chile is related to reduced predation pressure. By doing this, we hope to illuminate the shady side of predator-prey interactions. that is. those factors associated with the efficiency of predators in hunting for a particular kind of prey. The rabbit case is particularly appropriate for this type of analysis: we are dealing with a single prey species inhabiting ecolo g ically similar habitats under the pressure of different predator assemblages. Also. to further document the behavioural change of rabbits, we test the hypothesis that rabbits in central Chile could have changed their pattern of habitat utilization (spatial distribution between habitat patches). choosing areas of the chaparral with less shrub cover, therefore, with greater herb availability. The rationale is that under relatively low predation. selection of patches with fewer shrubs (potential refuges to escape predators). but with more herbs to feed upon. would be more profitable. The opposite would be true in the Spanish chaparral. where predation is high: consequently, nearby refuges (shrubs) would be more important than abundant food for survival of rabbits. MATERIAL AND METHODS Actual rabbit predators in southern Spain have been reported by Soriguer (1979). Predators likely to prey upon rabbits in the mediterranean habitats of central Chile were determined on the basis of their geographic distribution, abundance. habitat selection. and body size. Predators from both areas were matched primarily by taxonomic relatedness. and secondarily by size similarity. Matchings between Chilean and Spanish predators have also been discussed by Jaksic, Fuentes & Yanez (1979b) and Herrera & Jaksic (1980). Rabbit-eating habits of central Chile predators have been reported by Housse (1953). Greer (1965). Johnson (1965). Donoso-Barros (1966). Miller & Rottmann (1976). Jaksic. Fuentes & Yanez (1979a. b). Quantification of the importance of rabbits as prey in both areas is based on a review of published information. as well as personal communications

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when no published data are available. The information gathered is presented as number of rabbits (adult. juvenile. or kittens) in relation to the total count of vertebrates detected in the diet of a given predator. that is as percent occurrence of the vertebrate prey. By doing this we are underestimating the importance of rabbits as prey, since by being heavier than other prey they contribute greater biomass to predators ' diet (see Herrera & Jaksic 1980. for some prey weights in mediterranean Chile and Spain). However. this holds true in the two areas. thus renderin g our results comparable. Food data for Chilean predators were obtained from the following sources: Asio flammeus (Fulk 1976): Athene cunicularia (Jaksic et al. 1977: Pefaur. Jaksic & Yañez 1977: Jaksic 1979: Schlatter et al. 1980a. b); Bubo virginianus (Jaksic et al. 1977: Yañez. Rau & Jaksic 1978; Jaksic & Yanez 1980): Buteo poliosoma (Schlatter. Yanez & Jaksic 1980): Circus cinereus (rabbits are not considered to be part of its diet: see Johnson 1965): Dusicron culpaeus and Dusicron griseus (Yanez & Jaksic 1978a: Fuentes & Jaksic 1979a: Jaksic. Schlatter & Yariez 1980): Elanus leucurus ( Greer & Bullock 1966: Meserve 1977: Schlatter et al. 1980): Falco sparrerius (Yanez et al. 1980): Felis guigna ( Greer 1965): Geranoaetus melanoleucus (Schlatter. Yanez & Jaksic 1980): Grison cuja (anecdotal evidence sug g ests rabbits as prey: see Housse 1953. Miller & Rottmann 1976): Parabuteo unicinctus ( Greer & Bullock 1966: Yanez & Jaksic 1978b: Jaksic. Yanez & Schlatter 1980): Philodrras chamissonis (anecdotal evidence suggests rabbit kittens as prey: see Donoso-Barros 1966: H. W. Greene & F. M. Jaksic. unpublished): Strix rufipes (not known to eat rabbits: see Johnson 1965): Tyto alba (Reise 1970: Schamberger & Fulk 1974: Fulk 1976: Jaksic 1979: Jaksic et al. 1977: Jaksic & Yanez 1979. 1980: Herrera & Jaksic 1980). Photocopies of Chilean publications are available upon request to the first author. Nomenclature follows Osgood (1943) for mammals: Blake (1977) for falconiforms: Clark. Smith & Kelso (1978) for strigiforms: and Thomas (1977) for the snake Philodrvas chamissonis.

Data concerning the prey of Spanish predators were obtained from the following sources: Accipiter gentilis ( Araujo 1973: Garzon-Heydt 1973): Aegypius monachus (Garzon-Heydt 1973: Hiraldo 1976): Aquila chrysaetos (Elose g ui 1973: Garzon-Heydt 1973; Delibes. Calderon & Hiraldo 1975: Soriguer 1979); Aquila heliaca (Valverde 1967: Garzon-Heydt 1973: Delibes 1978b): Asio otus ( Araujo et al. 1973: Soriguer 1979): Athene noctua ( Delibes 1980: R. C. Sori g uer. unpublished): Bubo bubo (Hiraldo. Andrada & Parreio 1975): Buteo buteo (Valverde 1967: Garzon-Heydt 1973: Soriguer 1979): Canis lupus (Castroviejo et al. 1975): Circus prgargus ( Hiraldo. Fernandez & Amores 1975): Elaphe scalaris (Valverde 1967: Vericad & Escarre 1976): Falco subbuteo (Garzon-Heydt 1973): Fells lynx (Delibes 1977); Felis silvestris (Aymerich et al. 1979): Genetta genetta (Delibes 1974: Delibes 1980): Herpestes ichneumon ( Delibes 1976): Hieraaetus , fasciatus (Elose g ui 1973: Garzon-Heydt 1973: Arroyo. Bueno & PerezMellado 1976: Soriguer 1979): Hieraaetus pennatus ( Garzon-Heydt 1973: lribarren 1975): Malpolon monspessulanus ( Diaz 1976): Mantes foina ( Delibes 1978a). Mantes tnartes (Aritio 1970):Meles metes ( Delibes 1980): Milvus migrans (Valverde 1967: Garzon-Heydt 1973: Delibes 1975): Milvus milvus (Valverde 1967: Garzon-Heydt 1973): Mustela putorius (Ballarin et al. 1979):Neophron percnopterus ( Garzon-Heydt 1973: Delibes 1980): Strix aluco (Lopez Gordo 1973): Tyto alba (Valverde 1967: Herrera 1973a. b: Herrera & Jaksic; 1980): Vulpes vulpes (Amores 1975). Photocopies of Spanish publications are available upon request to the second author. We follow Corbet (1978) for nomenclature of mammalian predators: Brown & Amadon (1968) for falconiforms: Clark. Smith & Kelso (1978) for strigiforms: and Steward (1971) for the snakes.

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Weights of rabbit predators in Chile were obtained from Greer (1965); Greer & Bullock (1966); Schlatter et al. (1980); Yanez et al. (1980); Herrera & Jaksic (1980); and from the collections of the Museo Nacional de Historia Natural (Chile). Weight data for predators in Spain were obtained from Herrera & Jaksic (1980); Hiraldo, Fernandez & Amores (1975); and the collections of the Estacion Biologica de Donana (Sevilla). The habitat utilization by rabbits in central Chile and southern Spain was assessed by analysing in different habitat patches the relationship between shrub cover, estimated with the line-intercept method (Mueller-Dombois & Ellenberg 1974), and rabbit abundance, estimated by counting fresh pellets intercepted with a 30-m string (Chile) or contained within 5-m 2 quadrats (Spain). The study sites for this analysis were Fundo Santa Laura (33°04'S. 71°00'W). W of Santiago. Chile, and Reserva Biologica de Donana (36°58'N, 3°23'W), S of Sevilla, Spain. Detailed descriptions of Fundo Santa Laura are available in Thrower & Bradbury (1977); details about the study site in Reserva BiolOgica de Donna are reported by Rogers (1974) and Soriguer & Rogers (1980). Because percent shrub cover was measured in the same manner in the two areas, this habitat axis is common to both. Corresponding numbers of pellets in the field were obtained with different procedures; estimates for central Chile were calculated on a length unit, and those for Spain on an area basis. However. we are not interested in the absolute abundance of rabbits in Chile or Spain. but in the shape of the habitat utilization curves: thus, our results are comparable. RESULTS The mediterranean habitats of central Chile have a relatively depauperate predator fauna (Table 1). The four mammalian species present in central Chile strongly contrast to the ten mammalian predators in Spain. As compared to southern Spain, canids and felids are well represented, although by relatively smaller species in Chile; mustelids are strikingly scarce (one species in Chile v. four in Spain), and viverrids are not present. Regarding bird predators, the set of falconiforms in central Chile is half as diverse as in southern Spain, and represented by smaller species. The strigiforms' set is remarkably similar in central Chile and southern Spain. Snake predators in both areas are numerically unimportant. The Chilean fox ( Dusicyon culpaeus) is an adequate size-counterpart of V ulpes vulpes in Spain, but its consumption of rabbits (18 . 4%) poorly matches the 37% of rabbits in the diet of the European species; Dusicyon griseus, a smaller Chilean fox, infrequently includes rabbits in its diet. The only felid in the mediterranean habitats of central Chile ( Felis guigna) seems not to prey on rabbits. and this contrasts markedly with the high importance of rabbits as prey for Spanish felids. Even though our Chilean sample is small, the results obtained coincide with Miller & Rottmann's (1976) observation that Felis guigna does not prey on rabbits. This is probably not related to its small size, however. since feral domestic cats (Felis catus) are smaller than Felis guigna but nevertheless efficient rabbit predators in Great Britain (Lockley 1964) and Australia (Myers & Parker 1975). It is unfortunate that there are no quantitative data available on the food habits of the mustelid Grison cuja in central Chile, because it seems to be an appropriate counterpart (although somewhat larger and more heavy bodied) for Mustela putorius in southern Spain. that relies greatly on rabbits as prey (30% of its diet). On the other hand. Pearson (1957) has reported that Grison cuja forages in diurnal hours. when rabbits are hardly available. There is a good size match among four of the five accipitrid species found in central Chile (Elanus leucurus excluded) and corresponding species in southern Spain, but rabbit

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consumption by accipitrids is comparatively small in the mediterranean habitats of central Chile. This is particularly marked in the comparison between the congeners Buteo buteo (19 . 5% of its diet in southern Spain is made of rabbits) and Buteo polvosoma (6 . 1 % of rabbits in its diet in central Chile; see Schlatter, Yariez & Jaksic 1980). A parallel situation is exhibited by Circus pygargus (Spain) and Circus cinereus (Chile). although the difference is less striking. Note. moreover, that both Chilean species are of either si milar-size or larger than the Spanish ones: thus their dietary differences are not likely to be size-related. The Chilean Elanus leucurus has a Spanish counterpart in both size and hunting technique ( Elanus caeruleus). that does not prey on rabbits, but it is included in the comparison of predator assemblages because of its abundance in areas inhabited by rabbits in central Chile (see Schlatter et al. 1980). Both Parabuteo unicinctus and Geranoaetus melanoleucus also inhabit areas heavily infested with rabbits (see Jaksic. Yanez & Schlatter 1980; Schlatter. Yanez & Jaksic 1980). but, as documented in Table 1. their consumption of rabbits is low compared with the food habits of Spanish counterparts. Although the falconid Falco sparuerius is a rather small Chilean predator, it is included here because it could be expected to be able to hunt recently weaned kittens that are common during late winter and spring in the areas where it forages (see Yanez et al. 1980). The case of strigiforms in central Chile and southern Spain is particularly interesting because all the ecological counterparts are congeneric or even conspecific ( Tito alba is present in both areas). It is quite obvious that the Chilean strigids prey rarely upon rabbits when compared to the food habits of Spanish species. Again, this does not seem to be associated with size features, since Chilean owls (with the exception of Bubo virginianus) tend to be larger than their corresponding counterparts in Spain. Also. although the tytonid Tito alba is larger in Chile than in Spain. it includes almost no rabbits in its diet. This is the only case in which rabbits are not preyed upon to a larger extent in southern Spain than they are in central Chile. Jaksic & Yanez (1979) and Herrera & Jaksic (1980) discuss this situation in a different context. Due to the complete absence of quantitative data for snakes, no conclusion can be drawn about the importance of rabbits as prey of the Chilean species. However, by being able to enter rabbit burrows. it could be expected that Philodrvas chamissonis preys on nestlings and there is at least one observation of predation on a juvenile ( H. W. Greene & F. M. Jaksic, unpublished). In southern Spain, both Elaphe scalaris and Malpolon monspessulanus are known to eat kittens in burrows (Valverde 1967: S. D. Busack. pers. comm.). Considering the overall information on food habits of predators in southern Spain and central Chile, rabbits contribute on the average 20 . 6% of the vertebrate prey of twenty-nine species of Spanish predators. The figure is 2 . 0% in the diet of sixteen species of Chilean predators. A general comparison of predator sizes and of the importance of rabbits as prey in central Chile and southern Spain can be obtained by analysing the statistical distribution of these data in both areas with the Kolmogorov-Smirnov test (Sokal & Rohlf 1969). We obtained the following results: The frequency distribution of predator sizes is not significantly different (P > 0 . 30: two-tailed test). However. percent rabbits in the diet of predators is significantly smaller in the Chilean assemblage than in the Spanish one (P < 0 . 001: one-tailed test). The snake sets were not included in these calculations because of the lack of enough information on sizes and/or food habits. The habitat utilization curve in central Chile is clearly skewed toward lesser density of shrub cover, and that in southern Spain toward greater density of shrub cover (Fig. 1).

TABLE I. Predatory species in mediterranean habitats of central Chile and southern Spain. Their mean weight, number of vertebrate prey, and the contribution of rabbits to their diet (in both number and percentage) are shown. Predators in the two regions were matched primarily by their taxonomic relatedness, secondarily by their size similarity

* Estimate made by authors studying this species (see text for references). **Sample size is small but the figure coincides with estimate made by other authors (see text for references). ***Anecdotal evidence suggests that this species eats rabbits; observations not quantified.

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Fin. 1. Habitat utilization by European rabbits (0ryctolagus cuniculus) in chaparral areas of central Chile and southern Spain. Abundance, or activity, of rabbits in patches with different shrub cover was estimated by the average number of pellets per unit-transect (Chile = unfilled symbols; sample size to the right) or unit-area (Spain = filled symbols; sample size was ten for every point). The curves were fitted by eye; the ordinates were adjusted to generate similarlysized curves; the shape of them was not affected by this procedure because the abscissa remained the same.

According to this, the greatest abundance of rabbits in central Chile is found in patches with 20-30% shrub cover (open chaparral), while in Spain they are most abundant in patches with 70-80% shrub cover (dense chaparral). Distributions of rabbit abundance are . significantly different between Chile and Spain (Kolmogorov-Smirnov test, P < 0 05; twotailed test). The unmistakable impression from this analysis is that the low number of predatory species in central Chile coupled with the presumably low predation pressure upon rabbits has produced a marked change in habitat utilization; as compared with areas where they are native. DISCUSSION The relative scarcity of predatory species in the mediterranean habitats of central Chile could be causally related to the strong zoogeographic barriers that isolate central Chile from South American dispersal routes (Keast, Erk & Glass 1972; Duellman 1979). The barren Atacama Desert by the North. the Pacific Ocean by the West, and the high Andean Ranges by the East are all strong barriers for the dispersal of organisms (Osgood 1943; Formas 1979; Fuentes & Jaksic 1979b). The main ecological factor likely to determine the number and relative abundance of predatory species-that is, prey abundance-seems not to be a limiting factor in central Chile. Small mammal abundance in this area, as measured by capture per unit-effort, is substantially greater than in southern Spain. Schamberger & . . . Fulk (1974) obtained figures of 0 06, 0 13, and 0 34 individuals per trap-night in three habitat types in central Chile. and year-round trapping by Jaksic & Yaiiez (1978) in a . chaparral habitat gave a monthly average of 0 03 individuals per trap-night (ranging as . 07). In southern Spain trapping success usually ranges between 0 . 00 and 0 . 04 high as 0

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individuals per trap-night (with figures strongly skewed toward small values), as revealed by several years of small mammal trapping in many habitat types and nearly twenty localities (R. C. Soriguer, unpublished results). These results suggest that food resources for predators are relatively more abundant in central Chile than in southern Spain (see Herrera & Jaksic 1980. for further discussion). The reason why Chilean predators are also smaller than those in the corresponding Spanish assemblage is obscure. On the one hand. this could be related to higher colonization rates of central Chile habitats by smaller-sized species, the most likely to successfully invade an area and the less likely to go extinct (MacArthur & Wilson 1967; MacArthur 1972). On the other hand, it could be due to the lack of appropriately large prey (Rosenzweig 1966; McNab 1971). Fuentes & Jaksic (1979a) have shown that the spectrum of mammalian prey sizes (mostly rodents, with a few marsupials) is narrower in central Chile than toward the south of the country, thus giving partial support to this hypothesis. However, it is not known if predators in southern Chile tend to be larger, because of the lack of adequate regional surveys. The comparatively smaller size of predators in the Chilean assemblage is correlated with the reduced importance of rabbits as prey in central Chile. This could be determining the overall trend observed in this country. because in Spanish hunting sets the larger predators tend to prey more strongly on rabbits than the smaller ones (Delibes 1980). However, size per se does not seem to be the causal factor underlying low consumption of rabbits by the Chilean predators. In fact, the small percentage importance of rabbits in their diet is associated with smaller size (relatively to Spanish counterparts) in six cases ( Felis guigna, Parabuteo unicinctus, Geranoaetus melanoleucus. Falco sparverius, Bubo virginianus, and Strix rufipes). However, the same holds true in six other cases when they are actually larger (Dusicyon culpaeus, Buteo polvosoma, Circus cinereus, A sio flammeus, A thene cunicularia, and Tyto alba). For the remaining four species there is not enough information on sizes or diet to draw a conclusion. A more likely explanation for the low contribution of rabbits to the diet of Chilean predators could be related to the known differences in prey supply between Chile and Spain. Small mammals in the mediterranean habitats of central Chile not only are more abundant than in Spain (see Herrera & Jaksic 1980), but also are utilized by a smaller number of predatory species (Table 1). In addition, some prey species exhibit remarkably stable and high abundance throughout the year (e.g. Octodon degus; see Jaksic & Yanez 1978). Hence, since Chilean predators have co-evolved for a long time with the available native prey, they are likely to have become adapted to hunt for and to rely heavily on this kind of prey. It is conceivable, then, that the small importance of the European rabbit in the diet of central Chile predators could be due to their lack of behavioural adjustment (thus resulting in inefficiency) to hunt for this recently introduced prey. Therefore, Chilean predators would pass the rabbits by in favour of the abundant native prey. Jaksic, Fuentes & Yanez (1979b) have modelled this phenomenon using fitness set analysis (Levins 1968). Summarizing, the hypothesis that predation upon introduced European rabbits is lower in the mediterranean habitats of central Chile than in those of Spain finds support from the data we have presented. Although the Chilean predator assemblage is characterized by smaller component species. this fact is not sufficient to explain the phenomenon because ecological counterparts in Chile and Spain do not exhibit any clear trend in size. Instead, we suggest that the lower rabbit consumption in central Chile is better explained by the relatively higher abundance of native prey coupled with the reduced number of predatory species in the area. Both factors could have aided the co-evolutionary adjustment between

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predators and prey that render them more efficient at hunting native small mammals than the introduced European rabbits. This model explains why Chilean predators pass rabbits by and, consequently, why rabbits behave as if they were predator-free in central Chile (Jaksic, Fuentes & Yanez 1979a. b). Differences in habitat utilization patterns between central Chile and southern Spain give further support to this contention. ACKNOWLEDGMENTS We are grateful to Harry W. Greene and Stephen D. Busack for their valuable comments and editorial advice. Robert K. Colwell made helpful suggestions; Eduardo R. Fuentes helped in the collection of data on rabbit abundances in central Chile. Gene M. Christman drew the figure. REFERENCES Amores, F. (1975). Diet of the Red Fox ( V ulpes rulpes) in the western Sierra Morena (south Spain). Doi-Tana A cta V ertebrata (Spain). 2,221-239. Araujo, J. (1973). Falconiformes del Guadarrama suroccidental. A rdeola (Spain). 19, 257-278. Araujo, J., Rey, J. M., Landin, A. & Moreno, A. (1973). Contribucion al estudio del buho chico (A sio otus) en Espana. A rdeola (Spain). 19, 397-498. Aritio, B. (1970). V ida y costumbres de los mustelidos espanoles. Servicio de Pesca Continental. Caza y Parques Naturales. Madrid. Spain. Arroyo, B., Bueno, J. M. & Perez-Mellado, V. (1976). Biologia de reproducción de una pareja de Hieraaetus fasciatus en Espana central. Donana A cta V ertebrata (Spain). 3, 33-45. Aymerich, M., Palacios, F., Cuesta, L., Garton, J. & Castroviejo, J. (1979). Alimentación del gato montes (Felis silvestris Schreber. 1777) en España. A ctas de la 1° Reunion Iberoamericana de Zoologia de V ertebrados (La Rabida. Spain) (in press). Ballarin, L, Garzon, J., Palacios, F., Cuesta, L. & Castroviejo, J. (1979). Sobre alimentacibn del turon ( Putorius putorius L.. 1766) en Espana. A ctas de la I° Reunion Iberoamericana de Zoologia de V ertebrados (La Ribida, Spain) (in press). Blake, E. R. (1977). Manual of Neotropical Birds. University of Chicago Press. Chicag o. Illinois. Brown, L. & Amadon. D. (1968). Eagles, Hawks and Falcons of the W orld. Two volumes. McGraw-Hill. New York. N.Y. Castroviejo, J., Palacios, F., Garzon, J. & Cuesta, L. (1975). Sobre la alimentación de los cánidos ibericos. Proceedings of the X II International Congress of Game Biologists (Lisbon. Portugal). The Wildlife Society. Washington. D.C. Clark, R. J., Smith, D. G. & Kelso, L. H. (1978). W orking Bibliography of Owls of the W orld: with Summaries of Current Taxonomy and Distributional status. National Wildlife Federation. Washington. D .C. Corbet, G. B. (1978). The Mammals of the Palearctic Region: a Taxonomic Review. British Museum ( Natural History) and Cornell University Press. London and Ithaca. Delibes, M. (1974). Sobre alimentacibn y biologia de la Gineta ( Genetta genetta L.) en Espana. Donana A rea V ertebrata (Spain). 1, 143-199. Delibes, M. (1975). Alimentación del milano negro ( Milvus migrans) en Doñana. Huelva (Espana). A rdeola (Spain). 21 (volumen especial). 183-207. Delibes, M. (1976). Datos sobre la alimentacibn del meloncillo. ( Herpestes ichneumon widdringtoni Gray. 1842) en España. Sdugetierkundliche Mitteilungen. 24, 38-42. Delibes. M. (1977). Ecologia y comportamiento alimenticios de Lynx pardina ( Temrninck, 1824) en el Coto Doñana. Ph.D. Dissertation. Universidad de Madrid. Madrid. Spain. Deltbes, M. (1978a). Feeding habits of the stone marten. Martes foina (Erxleben. 1777) in northern Burgos. Spain. Zeitschrift fur Sdugetierkunde, 43, 282-288. Delibes, M. (1978b). Ecologia alimenticia del aguila imperial iberica ( A quila adalberti) en el Coto Doñana durante la crianea de los pollos. Donana A cta V ertebrata ( Spain ). 5.35-60. Delibes, M. (1980). The rabbit as prey in the Iberian Mediterranean ecosystem. Proceedings of the I W orld Lagomorph Conference ( Guelph. Canada) (in press). Delibes, M., Calderon, J. & Hiraldo, F. (1975). Seleccion de presa v alimentacion en Espana del águila real (A quila chrysaetos). A rdeola (Spain). 21 (volumen especial). 285-303. Diaz, C. (1976). Alimentación de la culebra bastarda ( Malpolon monspessulanus: Ophidia: Colubridae) en el suroeste de Espana. Donaña A cta V ertebrata (Spain). 3, 113-127.

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(Received 28 February 1980)

Introduction Material and methods Results Discussion Acknowledgments References Table I. Predatory species Fig 1. Habitat utilization by European rabbits

(oryctolagus cuniculus) in mediterranean habitats of ...

Chile they feed in open spaces between shrubs-independently of the distance between .... This is probably not related to its small size, however. since feral domestic .... Hence, since Chilean predators have co-evolved for a long time with the ...

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