Should the Common Buzzard Be Hunted?

Ornis Hungarica 2012. 20(2): 1–12. doi: 10.2478/orhu-2013-0006 Should the Common Buzzard be hunted?

TIBOR CSÖRGŐ1, RICHÁRD ZORNÁNSZKY2, TIBOR SZÉP3, PÉTER FEHÉRVÁRI4

Tibor Csörgő, Richárd Zornánszky, Tibor Szép, Péter Fehérvári 2012. Should the Common Buzzard be hunted? – Ornis Hungarica 20(2): 1–12.

Abstract The Common Buzzard is a widespread and abundant raptor in Europe. Recently, game keepers have argued that the buzzard population has increased in Hungary and is threatening valuable small game species. Hunting of the buzzard has been prohibited since 1933, and since 1954 it has also been protected by law, in Hungary. Here we review scientifi c literature on recent population changes of the species, prey composition, and anatomical constraints of foraging. We show that according to the Common Bird Monitoring Program the breeding population remained stable in 1992–2012. Because of its anatomy and its hunting techniques it is not able to hunt effi ciently for valuable small game. According to studies made with different methods in different parts of Europe in the last century, most of its prey species are small mammals. Therefore, the Common Buzzard population may help sustain rodent populations, thus providing essential ecosystem services for agriculture. Game species can also occur in the diet, however the proportion is negligible and buzzards usually acquire such prey as carcasses or handicapped individuals. We found no justifi cation in favour of lifting the hunting ban of Common Buzzards in Hungary.

Keywords: population change, anatomy, foraging method, wildlife management, prey composition

Összefoglalás Az egerészölyv Európa egyik leggyakoribb ragadozó madara. A hazai állomány is jelentős, 10 ezres nagyságrendű. 1933 óta élvez lelövési tilalmat, 1954 óta védett. Ennek ellenére az utóbbi években újra felmerült, hogy gyéríteni kellene a faj hazai állományát, mert annak nagysága jelentősen nőtt, ezért kártétele fokozódott. Az MMM 1999–2012-es felmérései szerint a faj állománya ebben az időszakban stabil volt. Anatómiai sajátosságai, vadásztechnikái miatt nem képes nagyobb testű, a vadgazdálkodásban érintett fajokat elejteni. Zsákmányállatainak nagyobb része – az utóbbi száz évben Európa különböző területein többféle mód- szerrel elvégzett vizsgálatok szerint – a mezőgazdaságban kártevő kisemlősökből kerül ki, amivel kimondottan nagy hasznot hajt. Mivel a táplálékmaradványokból ezek azonosítására kisebb az esély, mint a vadgazdálkodás szempontjából számbajöhető nagyobbakénak, ezek a számok még bizonyosan alá is becsülik az arányukat. A nagyobb testű állatok, vadgazdálkodás szempontjából hasznos fajok egyedei is szerepelhetnek az ölyv étlapján, de ezekhez legtöbbször az ember vagy valamely ügyesen vadászó ragadozó madár segítségével jut hozzá. Tevékeny- ségük mindenképpen hasznosnak tekinthető, vadászatukat semmi nem indokolja.

Kulcsszavak: állományváltozás, anatómiai sajátosságok, vadásztechnikák, vadgazdálkodás, táplálékösszetétel

1 Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, 1117 Budapest, Pázmány Péter sétány 1/c, Hungary, e-mail: [email protected] 2 Department of Zoology and Animal Ecology, Szent István University, 2100 Gödöllő, Páter Károly utca 1., Hungary 3 Institute of Environmental Sciences, College of Nyíregyháza, 4400 Nyíregyháza, Sóstói út 31/b, Hungary 4 Department of Zoology, Hungarian Natural History Museum, 1088 Budapest, Baross utca 13., Hungary 2 ORNIS HUNGARICA 2012. 20(2)

Introduction Population change

The Common Buzzard (hereinafter: buz- The European population increased be- zard) is amongst the most abundant and tween 1970 and 1990, then showed a slight widespread raptors in Europe. This species decrease. At the turn of the century the es- is divided into 6–8 distinct subspecies out timated number of breeding pairs was 710 of which the Hungarian population belongs thousand. The species’ status is evaluated as to the subspecies B. b. buteo. Ring recove- secure (BirdLife International 2004). ries show that buzzards are predominantly The Hungarian population of the species resident in the Carpathian Basin, however in recent decades of the last century – thanks a small proportion of birds may move to to nature conservation legislation and pub- neighbouring southern countries for winter. lic awareness – has increased (Haraszthy The wintering population is also comple- 2000). For instance in Békés county it went mented with birds from Scandinavia and up to 150 pairs from 100 pairs between 1990 the Baltic Region (Tóth 2009, Saurola et al. and 1995 (Tóth 1995 in Haraszthy 2000). At 2013). The birds of the eastern subspecies the turn of the century the breeding popu- (B. b. vulpinus) rarely migrate through Hun- lation was estimated to be between 10–20 gary (Hadarics & Zalai 2008). Since 1933 thousand pairs (Hadarics & Zalai 2008). the hunting of the buzzard has been prohi- Based on representative countrywide bited, and since 1954 it has been protected sampling (Szép & Nagy 2002), the Hun- by law (Haraszthy & Bagyura 1983). Game garian Common Bird Monitoring Program keepers, farmers and other stakeholders re- (MMM) estimated the population trends to cently raised the issue of lifting the protec- be stable for 1999–2012 (Szép et al. 2013). ted status, thus legalizing hunting as a form The mean annual population change in of controlling buzzards. These stakeholders this period (trend analysis, TRIM software argue that the population has considerably package, Pannekoek & van Strien 2001) did increased in recent years and that these bir- not show a signifi cant increase or decrease ds pose a serious risk for small game spe- (slope= 0.5% (SE=1.1%) (Figure 1). cies with high economic value. This debate The National Game Management Data- justifi ed that BirdLife Hungary elected the base on the other hand shows a somewhat species as the ‘Bird of the year’ in 2012 different trend; the numbers provided for (http://www.mme.hu/component/content/ these years are signifi cantly higher, moreo- article/19-hirek-archivum/1395-a-joev-ev- ver they show a 50% increase. In the 2003- egyik-eselyes-madara-segitseget-ker.html), 2004 hunting season they estimated 62911 raising wide public awareness of the issue. individuals, while in 2012-2013 this number Here we aim to review the international was 96237 (http://www.ova.info.hu/vadgaz- (British, Spanish, French, Danish, Norwegi- dalkodasi_statisztikak.htm). The underlying an, Polish, Czech, Slovak, Romanian) and reason in the deviation of the two estimates Hungarian studies conducted on Common is the different applied methodology. The Buzzards in relation to this debate. most obvious deviation is that the Common Birds Monitoring Program is a survey (i.e. systematic sampling of a population) while the National Game Management Database T. Csörgő, R. Zornánszky, T. Szép, P. Fehérvári 3

Figure 1. Population index of the Hungarian breeding population of the Common Buzzard according to data by the Common Bird Monitoring Program. The values of annual population indices and estimated indices SE are specifi ed in comparison to the base year (1999) 1. ábra Az egerészölyv magyar fészkelő állományának változása az MME Mindennapi Madaraink Monitoringja (MMM) adatai alapján. Az éves populációs indexek (imputed index) és a becsült indexek SE értékei a bázis évhez (1999) viszonyítva vannak megadva relies on a census (counting of all individu- Germany it is 0.42–2.17, in the Pilis hills als of a population). Furthermore, there is the estimated mean is 2.21 (Haraszthy & Ott a temporal difference between the two data 1984), and in Békés county it is 1.2–2 (Tóth series; the Common Bird Monitoring Prog- 1995 in Haraszthy 2000). In general, mean ram only uses data that derive strictly from fl edging success is less than 2 birds per nest. the breeding season (http://www.mme-mo- An indirect support of this general value is nitoring.hu/prog.php?datid=56) whereas the that the proportion of youngsters among ob- game management database only requests served birds is 31–51% in the Danish Strait that data providers count the number of every year (Forsman 2003). Returning to the individuals present and presumably inha- potential number of buzzards in the Hun- biting the game management area, without garian population; it is plausible that 50–55 any temporal restrictions (http://www.vmi. thousand individuals may be present in the szie.hu/adattar/pdf/adatlapok-2013/becs- post-fl edging period for a short time, but due les_terv-utmutato_2013.pdf). to natural and human induced mortality (elec- The common bird census program esti- trocution on medium voltage pylons, poison- mates an average 30000 individuals (i.e. ing, illegal hunting etc.) this number certainly 15000 pairs) for the country. Typically clutch decreases by autumn and winter. According size is 2–4 eggs (Cramp & Simmons 1980), to ringing data the mortality rate of the birds however fl edging success is considerably in their fi rst year is 46.4% (Germany), 65% lower, only 0.42–2.13 in the Swabian Alb (Sweden), 77.6% (Great-Britain) (Cramp & (Rockenbauch 1975), in other regions of Simmons 1980). Furthermore, individuals 4 ORNIS HUNGARICA 2012. 20(2) from northern Europe also migrate through breeding pairs per 100 km2 varied between or overwinter within the Carpathian basin as 40.8–437.3 annually, the territory of one pair suggested by ring recoveries, however asses- was between 209–245 hectares (Haraszthy & sing the ratio of resident vs. migrant buzzards Ott 1983), on the Northern-Borsod-Karst on is currently impossible. 30 thousand hectares 100–165 pairs bred bet- An equally important deviation between ween 1986 and 1991 (Varga & Rékási 1993). the two datasets is that they are acquired on This large variation may yield considerable different spatial scales. The Common Bird estimation bias if not controlled for. Monitoring Program covers a smaller spatial In summary, both methods have advanta- extent as the sampling is carried out on a frac- ges and disadvantages, however when as- tion of the total area of Hungary, although the sessing the countrywide breeding population sites and the observation points are randomly of buzzards, the Common Bird Monitoring chosen, thus allowing statistically sound esti- Program offers a more valuable estimate mates. On the other hand the National Game compared to the National Game Manage- Management Database holds information ment Database. Nonetheless, the demand for on the whole extent of Hungary, since all better understanding the breeding population game management units are legally obliged size and trends of common diurnal raptors, to present data annually. However, the lack MME/BirdLife Hungary launched a national of defi ned methodology allows data provi- Raptor Survey program that will hopefully ders to report numbers acquired with various allow an even more precise estimate of these techniques for each game management unit. fi gures in the future (http://www.mme-moni- Previously we have detailed that simply the toring.hu/php/dl.php?drid=2971). timing of fi eld observations within the season may remarkably infl uence the number of counted birds. Moreover, the game ma- Body structure and hunting nagement database does not specify how to method control for multiple counts of individuals, or for the spatial aggregation of individuals. The body structure of the buzzard determi- Buzzards and other raptor species often agg- nes the spectrum of accessible prey species. regate in areas with high prey densities, like Its feet, toes and talons are comparatively alfalfa fi elds or along large roads especially shorter than the sympatric and similar sized in winter. The reason for the latter is that ro- Goshawk (Accipiter gentilis). This later spe- ad-kills are often consumed by buzzards, and cies is considered to prey predominantly on also that roadside ditches are less likely to be birds (Widén 1987, Rutz & Bjilsma 2006) in infl uenced by rodenticides-but are often mo- forest habitats and therefore is built for high wed- thus presenting larger densities of prey maneuverability (Drennan & Beier 2003). with high prey accessibility compared to ot- Buzzards however have broader wings and her areas. A data provider may easily overes- shorter tails and thus are less maneuverable timate the number of buzzards present in the in fl ight (Norberg 1995). They can only hunt area based on observing these aggregations. prey with a maximum weight of 500 gramms, In the breeding season buzzards are terri- moving slowly on the ground, but since it is torial with variable territory sizes; in the Pilis an opportunistic predator, the prey is typically hills between 1977 and 1981 the number of much smaller (Cramp & Simmons 1980). T. Csörgő, R. Zornánszky, T. Szép, P. Fehérvári 5

The predation of buzzards is characteri- (Tubbs 1967, Graham et al. 1995, Swann zed by three strategies. In most cases they & Etheridge 1995, Kenward et al. 2001). In perch and wait either on the ground or on Romania, the typical prey species are rep- a vantage point and drop themselves on tiles (Dombrowski 1912), while in Spain, the prey moving on the ground at a smaller beside reptiles also insects and Rabbits con- distance. Buzzards can often be seen cro- stitute bulk of the prey items (Palaus Soler uching on molehills or on the mounds of the 1960, Garzón Heydt 1974, Bustamante 1985, Mound-building Mouse (Mus spicilegus). Mañosa & Cordero 1992). These individuals often do not even wait un- In some areas food composition can vary til their prey comes up to the surface, inste- with season. This may also be true for even ad they catch them by grabbing the moving Mediterranean areas where inter-seasonal sloppy soil (Skoczen 1962, Kalotás 1980). deviation of temperature is relatively low. The most abundant prey in the breeding period in Northeast Spain is the Rabbit. Buz- Food zard breeding season coincides with, or is possibly timed to the emergence of juvenile During more than a century, many different Rabbits. The second most frequent prey are methods have been used to analyze and ob- reptiles, dominantly Ocellated Lizard (La- serve the food of birds of prey. These include certa lepida). Also the importance of smaller for example stomach content, pellet- and birds became slightly stronger at this time of food remain analysis, observation, use of the year. This tendency was also supported cameras (Vasvári 1930, Witherby et al. 1939, by another investigation conducted in Spain Glutz von Blotzheim et al. 1971, Brown (Bustamante 1985). Furthermore, the role of 1976, Cramp & Simmons 1980, Kostrzewa reptiles may be less pronounced in the col- 2008). In general, food spectrum of buz zards der season, however amphibians can appear varies with climate, thus the predominant in large numbers in their diet as species of prey species in different populations may this taxa tend to aggregate around at specifi c be diverse along the breeding range. In most sites (Mañosa & Cordero 1992). of the range the main prey species are small Sex specifi c dietary differences are less mammals, dominantly the Common Vole pronounced compared to seasonal variation. (Microtus arvalis). This is also proven by In a study conducted in Spain the sto machs the fact that other than Hungarian, there are of males were empty more often, and small- also many other languages where we can fi nd er amphibians were found compared to fe- the word mouse in the name of the species: males. Remains of bigger rabbits were only German: Mäusebussard, Danish: Musvage, found in the stomachs of females. These dif- Icelandic: Músvákur, Norwegian: Musvak, ferences were explained by reversed sexual Finnish: Hiirihaukka, Spanish: Ratonero dimorphism (Mañosa & Cordero 1992). In Común, Polish: Myszolow, Slovak: Myšiaka contrast, other studies have not found sig- Horneho (Sandberg 1992), Serbian: Mišar. nifi cant sex specifi c differences in the diet in In Great Britain where the Common Vole regards to the species and size of their prey is not indigenous, the main prey species are (Bustamante 1985). birds, Rabbit (Oryc tolagus cuniculus) Lepus Prey composition may correlate with species and Field Vole (Microtus agrestis) nestling size; smaller nestlings may receive 6 ORNIS HUNGARICA 2012. 20(2) smaller prey species (e.g. earthworms and vole gradation years the average frequency voles), while larger nestlings are fed with was 75%, the weight proportion was 74%, more profi table prey like moles in a study while in low vole years these numbers were conducted by Meier et al. (2000). 40% and 48%. In these years the propor- Studies have shown high individual diffe- tion of earthworms, insects and amphibians rences in diet composition as well. For ins- increased signifi cantly while the proportion tance a male buzzard was observed to fora- of other mammals increased insignifi cantly ge on Slow Worms (Anguis fragilis), Sand (Kostrzewa 2008). Lizards (Lacerta agilis), European Adders Some buzzard pairs can be affected in dif- (Vipera berus), with only a single observa- ferent ways by different food availability. tion of vole as prey (Melde 1971). In cont- For some of them in the years when there rast, Kalotás’ (1985) observations suggest is a lack of voles, the breeding can fail, or that Mole consumption of some buzzard they lay fewer eggs. It can also occur that pairs can reach 40–50%. they interrupt breeding, in extreme situa- Even though some individuals can be real tions; their nestlings starve to death depend- specialists, the species is overall a gene- ing on how the breeding and the period of ralist, its food is basically limited by food the food shortage overlap with each other. availability. As opposed to this, there are buzzard pairs, The most common prey of buzzards is the which raise nestlings, though less in low Common Vole in most parts of the Europe- vole years. These shift food composition, an breeding range and thus the Carpathian the proportion of birds grows among prey Basin. According to a Slovakian study the animals (Kostrzewa 2008). The Mole can Common Vole can reach up to 96% of the also be an alternative prey in Europe. winter food composition (Salaj 1972). This In studies conducted in Poland the Mole vole species is active during the day and can appeared in larger numbers, than the Com- reach high densities in arable fi elds where mon Vole (Czarneczki & Foksowitz 1954). food abundance may be practically unlimi- The food consisted of 50% Moles and 33% ted. Every few years it manifests itself in Common Voles. According to the age studies gradation. In other years their numbers can based on dentition analysis the proportion of drastically drop, mainly due to climate fac- juvenile Moles was 86,5% compared to other tors (Gubányi & Horváth 2007). In vole gra- age groups in the whole sample. This is the dation years the proportion of the Common result of the behaviour of young Moles in the Vole in the prey composition is much bigger, start of their independent lives, in which the than in normal or poor vole years (Mebs activity near the surface or even above the 1964, Kalotás 1985, Kostrzewa 2008). surface is very typical (Skoczen 1962). The proportion of some animal groups can In contrast to continental Europe, the do- vary in the food composition depending on minant prey species in the British Isles are whether we take into consideration their we- Rabbits, while alternative prey are Field Vo- ight or their relative frequency (Kostrzewa les and birds (Graham et al. 1995). 2008). Despite this fact the proportion of the Predators can react to the changes in prey Common Vole is dominant both in vole gra- abundance in two ways. Generalist speci- dation years and between these years accor- es utilize alternative prey, while specialist ding to both indices in a study in Poland. In species are less fl exible hence their density T. Csörgő, R. Zornánszky, T. Szép, P. Fehérvári 7 changes. In case of the Common Buzzard, wet years. Other factors infl uencing repro- we can observe the combination of the two ductive success are interspecies competition reactions (Reif et al. 2004). and habitat quality. For instance, buzzards According to the previous statements, the breeding in nests near Goshawk territories Common Buzzard can change its food, if the were less successful, because the Goshawks density of the preferred prey animal decrea- often carried away their nestlings. The more ses, while there is a connection between the stable the breeding population is, the bigger size of the vole population and the density the breeding success will be, and the bigger of breeding pairs, clutch size and breeding sight fi delity is typical for habitats optimal success (Mebs 1964, Rockenbauch 1975, for the species (Kostrzewa & Kostrzewa Reif et al. 2004). 1994). The number of breeding pairs is also According to a study conducted in Ger- controlled by intraspecies competition (Mo- many, the number of breeding pairs increa- ore 1957, Cramp & Simmons 1980, Newton sed by 1/5 in vole gradation years, compa- & Marquiss 1986 in Kostrzewa & Kostr- red to low vole years. In high voles years the zewa 1994, Weber & Stubbe 2000). ratio of the clutches with 3-4 eggs was 91%, Among the winter weather factors, the while in the low vole years this value dec- temperature and the snow cover infl uence reased to 20%. The breeding success (i.e. the survival just in extreme cases (Joensen relative frequency of clutches that fl edged) 1968, Kostrzewa & Kostrzewa 1991). If se- was 70.8%, and 50%, respectively (Mebs vere cold is accompanied by thick and per- 1964). According to a study conducted in manent snow cover, they starve to death in Finland, nesting rate (i.e. number of active large numbers (Mebs 1964). nests / number of all territories) and its pro- Studies conducted in different parts of ductivity (i.e. number of nestlings / number Europe (Rörig 1903, Dombrowski 1912, of all territories) positively correlated with Uttendörfer 1952, Czarnecki & Foksowicz the studied years’ Microtus species density 1954, Moore 1957, Sladek 1957, Toufar (Reif et al. 2004). 1958, Palaus Soler 1960, Pinowski & Rysz- In none fi eld vole mediated environments, kovszki 1962, Skoczen 1962, Mebs 1964, the changes in densities of the main prey Tubbs 1967, Joensen 1968, Thiollay 1968, species show a similar correlation with buz- Melde 1971, Salaj 1972, Ryszkovszki et al. zard reproductive success, in Great-Britain 1973, Garzón Heydt 1974, Rockenbauch with the Rabbit (Moore 1957, Graham 1995, 1975, Bustamante 1985, Kostrzewa & Kostr- Swann & Etheridge 1995), while in forest zewa 1991, 1994, Mañosa & Cordero 1992, environment with the Bank Vole (Myodes Graham et al. 1995, Swann & Etheridge glareolus) (Weber & Stubbe 2000). 1995, Meier et al. 2000, Weber & Stubbe The population of buzzards depends not 2000, Kenward et al. 2001, Reif et al. 2004, only on food availability, at least three ot- Kostrzewa 2008), and also the inland studies her factors can play a part in the success of (Nozdroviczky 1907, Barthos 1908, Greschik breeding. As buzzards breed in unsheltered 1910, Bessenyei 1917, Greschik 1924, Tar- twig-nests, the amount of rainfall in May is ján 1939, Kalotás 1980, 1982, 1983, 1985, important. In rainy years the nestlings can Rékási 1981, Balogh & Varga 1983, Varga get soaked, thus they may chill and die. In 1984, Varga & Rékási 1993, Fenyősi 1994, dry years fl edging success is higher than in Bereczky 2010, Zornánszky et al. 2013) 8 ORNIS HUNGARICA 2012. 20(2) proved that the species eat primarily small found Pheasant remains in the stomachs of rodents, dominantly Common Voles. From buzzards, but in half of these cases (15.4%), spring to autumn – in changing proportion – it could be detected, that it was consumed insects and their larvas, amphibians, reptiles while already dead, because the Pheasant are also on its diet everywhere, and mainly in remains were contaminated by fl y larvae. winter, when these prey animals are not ac- In 19.2% of the samples he found the rema- cessible, it also eats different types of carrion ins of Pheasants younger than 7 weeks. The for example fi sh (Toufar 1958, Sladek 1961, relatively big occurrence of Pheasants can Kalotás 1982, 1985, Varga 1984). It can also be the effect of the collapse of the Common capture fl edglings or nestlings in small num- Vole population after the gradation in 1981. bers (Glutz von Blotzheim et al. 1971, Sa- In 1982 altogether 34.6% was the propor- laj 1972, Kalotás 1985, Swann & Etheridge tion of the Common Vole in their diet. 1995). Although according to some obser- In the southern part of Great-Britain they vations it attacks Hare (Lepus europaeus) collected food remains from 40 nests, and (Nozdroviczky 1907, Bereczky 2010), Grey followed the movement of 136 buzzards Partridge (Perdix perdix) (Bessenyei 1917) with radio telemetry with the aim of fi nd- and Pheasant (Phasianus colchicus), but the- ing a connection between the rate of preda- se are caught as youngsters or in an injured, tion, the presence of buzzards, movement weakened, sick state (Vasvári 1930, Glutz zone and the characteristics of the Pheasant von Blotzheim et al. 1971). pens. They found fresh Pheasant remains Bigger animals, valuable game species can in 7% of the controlled nests. Only 8% of also be on the diet of buzzards, but in most the radio-tagged buzzards had signifi cantly cases these are obtained with the help of hu- more association than other buzzards with mans or other more skilful birds of prey (Ut- pens. The characteristics of the pens (small tendörfer 1952, Toufar 1958). It cannot cope canopy coverage) and the release (lot of with an adult Hare (Balogh & Varga 1983). Pheasants in one pen) made it easy for the The dominance of the main prey animals buzzards to catch them. The proportion of did not change, where they artifi cially rai- Pheasants of the diet was not more than sed and released Pheasants (Kalotás 1982, 2.6% (Kenward et al. 2001). 1985, Kenward et al. 2001), or it is present In general, dietary studies show that small naturally in high numbers (Rékási 1981). rodents dominate both in proportion of we- According to studies conducted in the ight and frequency of buzzard diet throug- ‘80s, the Pheasants present in the diet of hout the European breeding range. Smaller buzzards are from two large sources; a) taxa are less likely to be discovered in dietary from killed or injured birds, typically cau- analyses, therefore the proportion of small sed by mowers (Farkas 1977), and b) sick or mammals is probably even underestimated poisoned birds (Farkas 1980). in these studies (Mebs 1964, Kalotás 1985, Kalotás (1985) in 1981, during the peak Graham et al. 1995, Kostrzewa 2008). In of a vole gradation, could only prove one addition, the parents are likely to consume instance of buzzards foraging on Pheasants the smaller animals on the spot of the cap- (0.9%), but the Common Vole was present ture, and bring only the bigger ones to the in 63.6% of the samples. In 1982, relatively nest (Mañosa & Cordero 1992, Graham et often, in 38.5% of the cases the author al. 1995). The analysis of pellets also cannot T. Csörgő, R. Zornánszky, T. Szép, P. Fehérvári 9 give a perfect idea of the spectrum of prey ging on relatively large game species like animals, because the diurnal birds of prey Pheasants or Hares. The buzzards are most digest most of the bones (Vasvári 1930, Ut- likely to catch sick, injured individuals (Vas- tendörfer 1952, Mebs 1964, Glutz von Blotz- vári 1930, Salaj 1962, Mebs 1964, Glutz von heim 1971, Kalotás 1982), the bigger ones Blotzheim et al. 1971, Kalotás 1982), so their are more likely to remain, so these are also activity can be regarded even useful. overrepresented (Uttendörfer 1952). The It was already stated a century ago – in a bromatologyc analyses can only provide in- period with a completely different approach formation on the prey caught directly before to birds of prey – that the agricultural be- the shooting (Vasvári 1930). The use of me- nefi t of buzzards surpasses the harm caused chanisms placed above the nest, collecting to game management (Greschik 1910, 1924, the prey animals dropped into the nest by Toufar 1958, Salaj 1972, Kalotás 1980, the parents can give a more complete idea 1982, 1983, 1985). Naturally the buzzards about the spectrum of prey animals and their cannot abolish gradation, but can effectively proportion (Czarnecki & Foksowicz 1954). participate in the reduction of the popula- Taking and analyzing of footage and pictu- tion’s number (Ryszkowski et al. 1973). res also do so (Meier 2000, Zornánszky et al. The demand to control buzzard popula- 2013), but probably the smaller prey animals tions to reduce foraging pressure on game are consumed by the parents more frequently species is not substantiated based on our re- than the bigger ones, because carrying them view of the vast literature cited in this paper. to the nest is more profi table. On the contrary, reducing the buzzard popu- In general, we found that the Hungarian lation would presumably result in less cont- breeding population of the buzzard is stab- rolled Field Vole gradations. le, and according to studies conducted with different methods in different areas and in different time periods throughout the past Acknowledgements century, the proportion of valuable game species in the diet of buzzards is negligible. We would like to express our gratitude to Presumably, this is caused by the fact that referees and Dániel Paizs, who made the they are anatomically less capable of fora- language corrections for the paper.

References Balogh, L. & Varga, Zs. 1983. Adatok a Sopron kör- – Heliaca 8: 91–92. (In Hungarian with English nyéki egerészölyv- és héja-állomány ökológiájához Summary) [Data for the ecology of the Common Buzzard and Bessenyei, I. 1917. Adatok a vörös vércse, egerész ölyv the Goshawk population in the neighbourhood of és karvaly téli táplálkozásához [Data regarding the Sopron]. – Tudományos Diákköri Dolgozat, Sop- winter diet of Kestrel, Common Buzzard and Spar- ron [nyomtatott anyag] (In Hungarian) rowhawk]. – Aquila 24: 278. (In Hungarian) Barthos, Gy. 1908. Néhány adat az egerészölyv táp- BirdLife International 2004. Birds in Europe: popula- lálkozásához [Some data regarding the diet of the tion estimates, trends and conservation status. – Common Buzzard]. – Aquila 15: 307–308. (In Cambridge, UK Hungarian) Brown, L. H. 1976. British birds of prey. – Blooms- Bereczky, A. Sz. 2010. Adatok az egerészölyv költés- bury Books, London és táplálkozásbiológiájához [Data on the breeding Bustamante Díaz, J. M. 1985. Alimentacíón del ratone- biology and the food of the Common Buzzard]. ro común (Buteo buteo, L. 1758) en el norte de Es- 10 ORNIS HUNGARICA 2012. 20(2)

paña [Food of the Buzzard (Buteo buteo, L. 1758) latok [Bromatologic and pellet analyses]. – Aquila in the north of Spain]. – Doñana, Acta Vertebrata 30-31: 243–263. (In Hungarian) 12(1): 51–62. (In Spanish with English Summary) Gubányi, A. & Horváth, Gy. 2007. Mezei pocok [Com- Cramp, S. & Simmons, K. E. L. 1980. Birds of Europe mon Vole]. – In: Bihari, Z., Csorba, G. & Heltai, the Middle East and North Africa – The birds of M. (eds.) 2007. Magyarország emlőseinek atlasza the Western Palearctic. – Oxford University Press [The atlas of Hungarian mammals]. – Kossuth Ki- Czarnecki, Z. & Foksowicz, T. 1954. Obserwajce do- adó, Budapest pp. 162–163. (In Hungarian) tyczace skladu pokarmu myszolowa zwyczajnego Hadarics, T. & Zalai, T. (eds.) 2008. Nomenclator Avi- (Buteo buteo L.) [Observations on the compo- um Hungariae [An annotated list of the birds of sition of the feed of Buzzard (Buteo buteo L.)]. Hungary]. – MME, Budapest (In Hungarian with – Ekologia Polska 2: 477–485. (In Polish with English Summary) English Summary) Haraszthy, L. & Bagyura, J. 1983. Ragadozóma- Dombrowski, R. 1912. Die Vogelwelt Rumanien’s dár-védelem az elmúlt 100 évben [Protection of [The Birds of Romania]. – Bucharest (In German) birds of prey in the last 100 years]. – Aquila 100: Drennan, J. E. & Beier, P. 2003. Forest structure and 105–225. (In Hungarian with English Summary) prey abundance in winter habitat of Northern Gos- Haraszthy, L. & Ott, J. 1984. Egerészölyv (Buteo bu- hawks. – The Journal of Wildlife Management teo) állomány vizsgálata a Pilis hegység területén 67(1): 177–185. 1977–1981 között [Study on the Buzzard stock Farkas, D. 1977. A lucernabetakarítás hatása a mezei- (Buteo buteo) in the area of the Mountain Pilis, nyúlra és a fácánra [Effect of medick harvest on between 1977 and 1981]. – Puszta 10: 11–18. (In the Hare and the Pheasant]. – Nimród 17: 1–4. (In Hungarian with English Summary) Hungarian) Haraszthy, L. (ed.) 2000. Egerészölyv [Common Buz- Farkas, D. 1980. Azodrin 40 WSC üzemi vadtoxiko- zard]. – In: Haraszthy, L. 2000. Magyarország lógiai vizsgálata kelésben levő napraforgóban és madarai [Birds in Hungary]. – Mezőgazda Kiadó, kukoricában [Game toxicological study of Azod- Budapest rin 40 WSC in sunﬂ ower and corn during sprou- Joensen, A. H. 1968. En undersogelse af ynglebestan- ting]. – Növényvédelem 16(11): 564–566. (In den af Musvage pa Als 1962 pa 1963 [An inves- Hungarian) tigation on the breeding population of the Buzzard Fenyősi, L. 1994. Adatok az egerészölyv (Buteo bu- (Buteo buteo) on the Island Als in 1962 and 1963]. teo) táplálkozásához [Data regarding the diet of – Dansk Ornitologisk Forening Tidsskrift 62: 17– the Common Buzzard]. – Madártani Tájékoztató 31. (In Danish with English Summary) 1993–94. p. 17. (In Hungarian) Kalotás, Zs. 1980. Eszi vagy nem eszi? [Does it eat or Forsman, D. 2003. The raptors of Europe and the Mid- not?] – Nimród 20: 250–252. (In Hungarian) dle East. – Christopher Helm, London Kalotás, Zs. 1982. Adatok az egerészölyv (Buteo bu- Garzón Heydt, J. 1974. Contribución al estudio del teo) táplálkozásához [Data regarding the diet of status, alimentación y protección de las Falco- the Common Buzzard (Buteo buteo)]. – Állattani niformes en Espana Central [Contribution to the Közlemények 69: 111–117. (In Hungarian) study of the status, food and protection of Falconi- Kalotás, Zs. 1983. Az egerészölyvek (Buteo buteo) formes in Central Spain]. – Ardeola 19: 279–330. vadgazdálkodási szerepének vizsgálata apróvad- (In Spanish with English Summary) dal dúsított vadászterületen [Study of the game Glutz von Blotzheim, U. N., Bauer, K. M. & Bezzel, management role of the Common Buzzard in a E. 1971. Handbuch der Vögel Mitteleuropas 4. territory enriched with winged game]. – Puszta [Handbook of the Middle-European Birds 4.]. – 10: 31–35. (In Hungarian with German Summary) Akademische Verlagsgesellschaft, Frankfurt am Kalotás, Zs. 1985. Újabb adatok az egerészölyv (Bu- Main (In German) teo buteo) táplálkozásához [New data on the food Graham, I. M., Redpath, S. M. & Thirgood, S. J. of Common Buzzard (Buteo buteo)]. – Állattani 1995. The diet and breeding density of Common Közlemények 69: 85–93. (In Hungarian with Eng- Buzzards Buteo buteo in relation to indices of lish Summary) prey abundance. – Bird Study 42(2): 165–173. Kenward, R. E., Hall, D. G, Walls, S. S. & Hodder, K. doi:10.1080/00063659509477162 H. 2001. Factors affecting predation by Buzzards Greschik, J. 1910. Hazai ragadozómadaraink gyo- Buteo buteo on released Pheasants Phasianus mor- és köpettartalom vizsgálata [Bromatologic colchicus. – Journal of Applied Ecology 38: 813– and pellet analyses of birds of prey]. – Aquila 17: 822. doi:10.1046/j.1365-2664.2001.00636.x 168–179. (In Hungarian) Kostrzewa, A. 2008. Nahrungswahl von Mäusebussard Greschik, J. 1924. Gyomor- és köpettartalom vizsgá- Buteo buteo und Habicht Accipiter gentilis – eine T. Csörgő, R. Zornánszky, T. Szép, P. Fehérvári 11

Metaanalyse rheinischer und europäischer Daten der Rékási, J. 1981. Adatok az egerészölyv táplálkozásá- letzten hundert Jahre [Food selection of Common hoz fi ókanevelés idején [Data regarding the diet of Buzzards Buteo buteo and Goshawks Accipiter gen- the Common Buzzard in breeding time]. – Madár- tilis – a metaanalysis of data from Europe and Ger- tani Tájékoztató jan-febr-márc. pp. 232–233. (In many from the last one hundred years]. – Charadrius Hungarian) 44(1): 1–18. (In German with English Summary) Rockenbauch, D. 1975. Zwölfjahrige Untersuchungen Kostrzewa, A. & Kostrzewa, R. 1994. Population zur Ökologie des Mäusebussards (Buteo buteo) limitation in Buzzards Buteo buteo and Kestrels auf der Schwabischen Alb [12-year’s study of the Falco tinnunculus: the different roles of habitat, ecology of the buzzard in the Schwabische Alb]. – food and weather. – Raptor Conservation Today Journal für Ornithologie 116: 39–54. (In German) WWGBP, Berlin pp. 39–48. Rutz, C. & Bijlsma, R. G. 2006. Food-limitation in a Kostrzewa, R. & Kostrzewa, A. 1991. Winter wea- generalist predator. – Proceedings of the Royal ther, spring and summer density, and subsequent Society B 22 273(1597): 2069–2076. doi:10.1098/ breeding success of Eurasian Kestrels, Common rspb.2006.3507 Buzzards and Northern Goshawks. – The Auk 108: Ryszkowski, L., Goszczynski, J. & Tuszkowski, J. 342–347. 1973. Trophic relationship of the Common Vole Mañosa, S. & Cordero, P. J. 1992. Seasonal and sexual in cultivated fi elds. – Acta Theriologica 18(7): variation in the diet of the Common Buzzard in 125–165. Northeastern Spain. – Journal of Raptor Research Salaj, J. 1972. Potrava myšiaka horného (Buteo buteo) 26(4): 235–238. z oblastí Lučenca a Šiah r. 1956–1961. [Food of Mebs, T. 1964. Zur Biologie und Populationsdynamik the Common Buzzards in the region of Lucenec des Mäusebussards (Buteo buteo) [About the bio- and Sahy in the years 1956–1961]. – Biológia 17: logy and population dynamics of the Buzzard]. – 537–542. (In Slovak with German Summary) Journale für Ornithologie 105: 247–306. (In Ger- Sandberg, R. 1992. European bird names. – Anser man with English Summary) Suppliment 28, Lund Meier, B., Stubbe, M. & Fehlberg, U. 2000. Unter- Saurola, P., Valkama, J. & Velmala, W. 2013. Suomen suchungen zur Nahrungsökologie des Mäuse- Rengastusatlas 1. [The Finnish Bird Ringing Atlas bussards (Buteo buteo) im Geestbereich Schles- 1.]. Luomus (In Finnish with English Summary) wig-Holsteins [Investigations on feeding ecology Skoczen, S. 1962. Age structure of skulls of the Mole, of the the Common Buzzard (Buteo buteo) in the Talpa europea Linnaeus 1758. from the food of geest area of Schleswig-Holstein]. – Populations- the Buzzard (Buteo buteo L.). – Acta Theriologica ökologie Greifvogel und Eulenarten 4: 223–232. 6(1): 1–9. (In German with English Summary) Sladek, J. 1961. Príspevok k poznaniu potravnej eko- Melde, M. 1971. Der Mäusebussard [The Common lógie myišiaka lesného Buteo buteo (L.) [Data for Buzzard]. – Neue Brehm Bücherei, Wittenberg the knowledge of the Buzzard’s (Buteo buteo L.) Lutherstadt (In German) food ecology]. – Zoologické Listy 10: 331–344. Norberga, U. M. 1995. Wing design and migratory (In Slovak with German Summary) fl ight. – Israel Journal of Zoology 41(3): 297–305. Swann, R. L. & Etheridge, B. 1995. A comparison of doi: 10.1080/00212210.1995.10688801 breeding success and prey of the Common Buz- Nozdroviczky, L. 1907. A Buteo buteo (L.) nyúlvadá- zard Buteo buteo in two areas of northern Scot- szata [Hare hunting of Buteo buteo (L.)]. – Aquila land. – Bird Study 42(1): 37–43. doi:10.1080/ 14: 319. (In Hungarian) 00063659509477146 Palaus Soler, F. J. 1960 Notas ornitologicas del No- Szép, T. & Nagy, K. 2002. Mindennapi Madaraink reste de España [Ornithologic notes of Northeast- Monitoringja (MMM) 1999–2000 [Hungarian Spain]. – Ardeola 6: 222–233. Common Bird Monitoring Program (MMM) Pannekoek, J. & van Strien, A. J. 2001. TRIM 3 Ma- 1999-2000]. – MME/BirdLife Hungary, Budapest nual. Trends and indices for monitoring data. – (In Hungarian) Research paper no. 0102. Szép, T., Nagy, K., Nagy, Zs. & Halmos, G. 2013. Pinowski, J. & Ryszkovszki, L. 1962. The Buzzard’s ver- Po pu lation trends of common breeding and win- satility as a predator. – British Birds 55: 470–475. tering birds in Hungary, decline of long-distance Reif, V., Jungell, S., Korpimaki, E., Tornberg, R. & migrant and farmland birds during 1999–2012. – Mykra, S. 2004. Numerical response of Common Ornis Hungarica 20(2): 13-63. Buzzards and predation rate of main and alterna- Tarján, T. 1939. Egérjárás és ragadozómadárgyüle- tive prey under fl uctuating food conditions. – An- kezés [Mouse invasion and bird of prey assem- nales Zoologici Fennici 41: 599–607. blage]. – Aquila 42: 686. (In Hungarian) 12 ORNIS HUNGARICA 2012. 20(2)

Thiollay, J. M. 1968. Régime alimentaire de nos ra- zard and the Goshawk in the region of Sopron and paces: quelques analyses francaises [The diet of in the Börzsöny]. – Diplomaterv Nyugat-magyar- our birds of prey: some French analyses]. – Nos országi Egyetem, Sopron (In Hungarian) Oiseaux 29: 249–269. (In French) Vasvári, M. 1930. Az egerészölyv és gatyásölyv Tóth, L. 1995. A Békés megyei ragadozómadár állo- táplálkozása [The diet of the Buzzard and the mány helyzete és változásai 1990–1995. [Situa- Rough-legged Buzzard]. – A természet 27: 281– tion and changes of the population of birds of prey 282. (In Hun garian) in Békés county]. – MME Kiadvány p. 55. Weber, M. & Stubbe, M. 2000. Nahrungsangebot und Tóth, L. 2009. Egerészölyv [Common Buzzard]. – In: Nahrungswahl von Rotmilan (Milvus milvus) und Csörgő, T., Karcza, Zs., Halmos, G., Magyar, G., Mäusebussard (Buteo buteo) im nordöstlichen Gyurácz, J., Szép, T., Bankovics, A., Schmidt, A. Harzvorland nach 1990 [Food supply and diet of & Schmidt, E. (eds.) 2009. Magyar madárvonulási Red Kite (Milvus milvus) and the Common Buz- atlasz [Hungarian Bird Migration Atlas]. – Kos- zard (Buteo buteo) in the northeastern Harz fore- suth Kiadó, Budapest pp. 221–224. (In Hungarian land after 1990]. – Populationsökologie Greifvo- with English Summary) gel und Eulenarten 4: 203–222. (In German with Toufar, J. 1958. Příspěvek k poznání potravy mladých English Summary) kání lesních (Buteo buteo) podle zbytků koristi Widén, P. 1987. Goshawk predation during winter, na hnízdec [For the knowledge of the food of the spring and summer in a boreal forest area of Common Buzzard nestlings]. – Sylvia 15: 67–76. central Sweden. – Ecography 10(2): 104–109. (In Czech with German Summary) doi:10.1111/j.1600-0587.1987.tb00745.x Tubbs, C. R. 1967. Population study of Buzzards in Witherby, H. F., Jourdain, F. C. R., Ticehurst, N. F. & the New Forest during 1962–66. – British Birds Tucker, B. W. 1939. The handbook of British birds 60(10): 381–395. 3. H. F. & G. Withery LTD, London Uttendörfer, O. 1952. Neue Ergebnisse über die Er- Zornánszky, R., Pomichal, K., Molnár, I. L. & Csörgő, nahrung der Greifvögel und Eulen [Newer results T. 2013. Aktuális-e az egerészölyv vadászata? [Is regarding the diet of birds of prey and owls]. – the hunting of the Buzzard timely?] – 5. Szünzoo- Eugen Ulmer Stuttgart (In German with English lógiai Szimpózium, Vácrátót (In Hungarian) Summary) http://www.mme.hu/component/content/arti- Varga, Zs. & Rékási, J. 1993. Adatok az Észak-Borso- cle/19-hirek-archivum/1395-a-joev-ev-egyik-ese- di Karszton fészkelő ragadozómadarak táplálko- lyes-madara-segitseget-ker.html zásához és állományváltozásaihoz az 1986–1991 http://www.mme-monitoring.hu/prog.php?datid=56 közötti időszakban [Food and population dyna- http://www.mme-monitoring.hu/php/ mics of birds of prey]. – Aquila 100: 123–136. (In dl.php?drid=2971 Hungarian with English Summary) http://www.ova.info.hu/vadgazdalkodasi_statisztikak. Varga, Zs. 1984. Az egerészölyv és a héja ökológiájá- htm nak vizsgálata Sopron környékén és a Börzsöny- http://www.vmi.szie.hu/adattar/pdf/adatlapok-2013/ ben [Study of the ecology of the Common Buz- becsles_terv-utmutato_2013.pdf