OCCURENCE OF THE LONG-LEGGED BUZZARD (BUTEO RUFINUS) IN THE HORTOBÁGY BETWEEN 1976 AND Dr. Gábor Kovács Hortobágy National Park.

Átírás

1 AQUILA VOL.: 99 (41^8) OCCURENCE OF THE LONG-LEGGED BUZZARD (BUTEO RUFINUS) IN THE HORTOBÁGY BETWEEN 1976 AND 1991 Dr. Gábor Kovács Hortobágy National Park Abstract Occurence of the Long-legged Buzzard (Buteo rufinus) in the Hortobágy between 1976 and 1991 The most characteristic place of occurence of the Long-legged Buzzard in Hungary is the Hortobágy. During the penod between 1976 and 1991 this species was seek on a total of 232 óccasions in this area. During specimens staying here from spring to autum were noted and also overwintering ones in The increases in the number of oberseniations indicate the extension of the area of the Long-legged Buzzards and a slow growth in the population, inord accumulated during 15 years are analysed here, indluding the habitat requirements, feeding, behaviour and moult patterns of this speces. Introduction Since the turn of the Century occurrences of the Long- legged Buzzard have been frequently observed by domestic bird-watchers. Occurence records of this characteristic steppe predator of East-Europe for the period between 1898 and 1959 have been reported by Sterbetz (1960), indicating nearly all the Hortobágy data published until The series of data including the entire territory of Hungary, even the regions beyond the frontier belonging to the Carpathian Basin reveal that the Long-legged Buzzard has occured in the Plain, the Eastern part of the country. The Long-legged Buzzard was first observed in the Hortobágy in 1908 (Szomjas, G. 1909) since then its presence has been reported more and more frequently (Szomjas, G. 1911, 1917, 1919; Szomjas, L., 1924; Újvárosi, 1925; Vasvári, 1928; Udvardy, 1941). Its occurrences in the Hortobágy have become so regulär that not only oversummering but a possible nesting of the bird is suggested e. g., by Udvardy. This latter has not been evidenced so far, however. During the fifties and sixties the Hortobágy was again the place most frequented by the species. (Lelovich 1962; Sóvágó, 1975; Sterbetz, 1967; 1972). Since 1970 it has often been watched by László Vilmos Szabó in the Southern puszta areas (Horváth, Szabó, 1981). Fintha (1975) has collected several records on the bird in the middle and Northern parts of the Hortobágy. Again Fintha could observe the most abundant colonies in the 41

2 Hortobágy (14-15 speciemens a day) in the district of Ohat, Margita, Darássá and Bagota from 20 August to 16 October, On 6 October, 1987 he counted specimens in a single grass field near Hajdúbagos, representing the domestic record (Fintha, in litt). Material and method During period between May, 1976 and November, 1991 I observed the Long-legged Buzzard in the Hortobágy on a total of 232 occasions The additional data enables a more datailed analysis of the migration which has taken place during the last one and a half decardes. Besides, it is also noteworthy to mention some conspicious events such as early arrival, lateautumn occurence, succesfull overwintering, feeding observations and change of habitats. Spring arrival In the literature there is only one old dátum available on the spring migration of the Long-legged Buzzard: on 6 april, 1925 Újvárosi watched the birds in the vicinity of Hajdúböszörmény (Pród? Bagota? ) (In: Warga, 1928). My personal series of data contain 7 spring observations: 26 May, Pentezug 11 April, Borzas 19 March, Kunmadaras 30 March, Ágota 18 April, Angyalháza 6 April, Karcag 27 May Kunmadaras The first seven data between 19. March and 27. May (during 16 years) indicate an insignificant spring migration from which the Long-legged Buzzard can not be considered as a regulär spring migrant in our region during March and May. It is questionable, whether early data in can be considered as a beginning of a more frequent spring occurence, or not? The Suggestion will only be answered during the next years. Summer occurence, oversummering Early-summer (early-june) data has become regulär since the eighties. Since then the Long-legged Buzzard has been consired as a summer-autumn gest. Its earliest summer occurence was on 3 June (1986, 1989). During the first two months of the summer their numbers amount only to 4 5 specimens but then there is a considerable increase during late-summer. 42

3 Autumn occurence The maximum frequency of the Long-legged Buzzard in the Hortobágy is from early-september to mid-october. During this period the birds occur in all parts of the puszta so that 4 5 or more specimens can be seen a day. According to my estimates (based on visits of to 8 10 areas within two-three days) on an average 10-12, (since 1988 it has increased to 14 and 18) specimens are stayling simultaneously in the Hortobágy. The late-october occurences are infrequent, and only expectional specimens can be seen in November (1985, unpublished). Based on personel data and those of István Fintha (Pers. comm.) the first ten days of October can be mentioned as an interesting assembling period. The majority of the birds immigrate from our area at mid-october. Overwintering There are two records of winter occurence or owerwintering in the literature. In one case was reported in Kazán and was considered for a long time the only wintering record in the country (Lambrecht, 1913). During the 1988/89 winter I continuously watched, and aduit specimen overwintering succesfully between 27 December and 13 March. Its overwin- Table 1. Occurrences of the Long-legged Buzzard in the Hortobágy between and táblázat. A pusztai ölyv közötti hortobágyi előfordulásai Year fa- Earliest Latest Daily maximum Estimated stock of the sps. Hortobágy, sps. Év Adatok száma Legkorábbi Legkésőbbi Napi maximum (pd.) A Hortobágy becsült állománya (pd.) Máj. 26. Okt Júl.22. Szept Aug. 19. Szept Aug. 23. Szept júl.3. Okt Jún. 4. Aug Apr. 11. Okt Júl.4. Okt Jún. 19. Okt Jún.28. Nov jún. 3. Szept jún. 7. Okt Jún. 25. Dec Jan.l. Okt Márc. 19. Okt Ápr. 6. Nov

4 tering can be explained by a very dry vole-infestated summer followed by a mild winter poor in precipitation which offered abundant rodent food for the buzzard (Kovács, 1989). Thus, winter occurence can be considered as an exceptional case. Month Hónap Table 2. Monthly distiibution of the records on the Long-legged Buzzard ( ) 2. táblázat. A pusztai ölyv-adatok ( ) havi megoszlása No. of occurrence A megfigyelések száma Jan. - Január 2 Feb. - Február 2 March - Március 4 April-Április 3 May - Május 2 June Június 14 July-Július 42 August - Augusztus 65 Sept. - Szeptember 56 Oct. - Október 39 Nov. - November 2 Dec. December 1 Total: Összesen: 232 Habitat In the Hortobágy the Long-legged Buzzard mainlv visits the dry habitats within these the order of preference of the habitat types is as follows: - loess bucks, barrows - sodic puszta-grass, sodic benches Heids: stubble, ploughed stubble, alfalfa cultüre environment: abandoned building, ruins, wells in the puszta, flood-gates, lightning rods, seratching posts, nature protection boards etc. For comparison the Bihar records (Konyár, Esztár, Nagykereki, Hosszúpályi, Biharkeresztes, Derecske) also originate from grassy puszta areas, arable land and barrows (Kovács, 1986; Fintha and Kovács, 1988). According to the observations of István Fintha (Pers. comm.) the Long-legged Buzzard also frequently occurs in the region of Szatmár and Bereg, a forested environment. Contrary to this, it can occassionally be seen in the bigger forests of the Hortobágy most by on the edges of the forests (Ohat, Margita, Ágota). The bird is absent from the ílood area forests. It is rather infrequent in aquatic habitats. I observed the species on some occasions but 44

5 only by fish-ponds and in rice-fields (Kovács, 1988). Lines of trees marginating rivers, canals and woodspots in the puszta are preferrend habitats. The specimens staying here for a longer period use permanent sleeping places (wells, trees) even when leaving the grassy areas for feeding in arable land, stubble and alfalfa Fields. Some very characteristics sleeping places used over years are e.g., the Vadálló well at Angyalháza, the Ancsán well at Szelencés, the big poplar tree of Redemtpus in the Kunmadaras puszta and the ruined sheep-fold of the Elek farm at Cserepes. Feeding data In the Hortobágy in the loess-buck grass and around the burrows the ground squirrel (Citellus citellus) occurs frequently providing the main prey not only for thejust spreading Saker (Falco cherrug) and the Imperial Eagle (Aquila heliaca) appearing here more and more regularly, but for the Long-legged Buzzard, as well. At the resting places used regularly by the buzzards I found plenty of casts containing mainly squirrel fragments (Kalotás, 1986.). Hamsters (Cricetus cricetus) and Common voles (Microtus arvalis) are also frequent items indicating the field activity of the Long-legged Buzzards. Kalotás (1992) has found fragments of locusts, grasshoppers and other insects in the pellets collected under the sitting-tree of an oversummering specimen. I couldn't observe this frequently as the buzzard was preying on these items while Walking. In 1985 watched a Long-legged Buzzard specimen preying on ayoung guineafowl in the Nagyiván puszta, on an other occasion it preyed on hens of 1-2 months old and ate them on the top of a hayrick. I have never seen it preying on Carrions. Behaviour The Long-legged Buzzard appears for the most part singly even if its species-mates are present in the area within eyeshot. It is seldom that the same sleeping tree is used by two specimens or that the specimens can approximate or tolerate one another within a distance of m. Only specimens circling in the air may form a loose-group of 3-4 birds. It may occur in the Company of other avian species, again while circling, accidentally. It is difficult to discover any regularity in such cases thus, I attempt only to give the order of frequency of the various species: Buzzard (Buteo buteo) Short-toed Eagle (Circaétus gallicus) Montagu's Harrier (Circus py gargus) Hen Harrier (Circus cyaneus) Marsh Harrier (Circus aeruginosus) Rough-legged Buzzard (Buteo lagopus) 45

6 White Storke (Ciconia ciconia) Lesser Spotted Eagle (Aquila pomarina) Impearial Eagle (Aquila heliaca) Black Stork (Ciconia nigra) Saker (Falco cherrug) I have frequently noticed that the Long-legged Buzzards sitting in stubbles (also in corn-stubble), alfalfa fields have been surrounded by rook folks, (occasionally) feeding at a distance of m. The wild geese visiting sowings, and corn-stubble in big masses are more watchful and often frightened of the predator flying there. During field observations the Long-legged Buzzards have appeared distrustful and watchful on nearly every occasion. Fortunately, I met some very tarne specimens approachable to m, contrary to the usual m. Young specimens, colour variations, moult Based on feathers, approximately % of Long-legged Buzzards appearing on the Hortobágy are old and even senile. In certain years no young birds were seen whilst, in other years 3 4 young specimens occured. The specimens belonging to the red-colour variety occur with a frequency of 15-20%, compared to the more frequent light-coloured variety with the occasional presence of gull coloured senile specimens with white-tails. Moulting of birds staying here takes place by the end of summer. Plenty of different feathers were collected from their resting palces (wells, barrows, ruins) and under the sleeping trees, e. g., tail feathers suitable for aging. Series of datas accumulated during 16 years The data collecting sites included not only the territory of the Hortobágy National Park, but unprotected parts of the Puszta and surroundings of the nearby Settlements (Karcag, Püspökladány, Nádudvar, Tiszafüred, Egyek, Tiszaörs, Balmazújvárso), as well. Instead of listing, the Observation data is tabulated indicating the total records, the earliest and latest dates as well as the maximum daily number of specimens and the estimated stock of the Hortobágy according to year (Table 1). Table 2 represents the monthly distribution of the data. Acknowledgement I want to express my thanks to István Fintha head of nature protection department (HNP) for his kind consent to publish his records obtained in the Hortobágy, Hajdúbagos and the Szatmár-Bereg region. The kind assistance Sándor Konyhás offered during the field visits in the Southern-East puszta areas of the Hortobágy is also acknowledged. 46

7 REFERENCES - IRODALOM Fintha, I. (1976): Ritkább ragadozómadarak a Hortobágyon 1973-ban. Aquila, Fintha, I.-Kovács, G. (1988): Pusztai ölyv. In: Haraszthy L. (szerk.) Magyarország madárvendégei Horváth, L.-Szabó, L. V. (1981): The Ornis of the Hortobágy. In: The Fauna of the Hortobágy National Park Kalotás, Zs. (1986) Adatok ragadozómadaraink táplálkozásához. Mad. Táj okt.-dec Kalotás, Zs. (1992) Néhány adat a Hortobágyon vendégeskedő pusztai ölyvek (Buteo rufinus) táplálkozásához. Mad. Táj. jan.-jún. (in print.) Kovács, G. (1986): Madártani megfigyelések Hosszúpályi, Konyár és Esztár környékénekszikes tavain ( ). Bihari Múz. Évk. IV-V Berettyóújfalu. Kovács, G. (1988): A Hortobágy madárvilágának öko-faunisztikai vizsgálata, In: Tóth A. (szerk.): Tudományos kutatások a Hortobágyi Nemezti Parkban, Kovács, G. (1989): Pusztai ölyv (Buteo rufinus) áttelelése a Hortobágyon. Mad. Táj. 1989/ Lambrecht, K. (1913): Az 1911/1912. évi télen áttelelt fajok jegyzéke. In: A madárvonulás Magyarországon... Aquila, Lelovich, Gy. (1962): A Hortobágy ragadozó madarai. Aquila, Sóvágó, M. (1975): Hortobágyi madármegfigyeléseim. Hajd. Múz. Évk. II Hajdúböszörmény. Sterbetz, I. (i960): Der Adlerbussard (Buteo rufinus) in Ungarn. Ornith. Mitteil Sterbetz, 1. (1965): évi megfigyelések a Hortobágy madárvilágáról. Déri Múz. Évk Debrecen. Sterbetz, I. (1972): évi adatok a Hortobágy madárvilágáról. Déri Múz. Évk Debrecen. Szomjas, G. (1909): Jegyzetek a Hortobágyról. Aquila, Szomjas, G. (1911): Buteo ferox a Hortobágyon... Aquila, Szomjas, G. (1917): Madártani jegyzetek a Hortobágyról az és 1917-évekről. Aquila, Szomjas, G. (1919): Madártani hírek a Hortobágyról az évről. Aqula, Szomjas, L. (1924): Buteo ferox adatok. Aquila, Udvardy, M. (1941): A Hortobágy madárvilága. Tisia, pp. Ujvárosy, 1. (1928): Tavaszi vonulás In. Warga K.: Madárvonulási adatok Magyarországból. Aquila, Vasvári, M. (1928): A vörösnyakú lúd téli szállása állatföldrajzi megvilágításban. Aquila, Author's address: Dr. Gábor Kovács Nagyiván Bem apó u. 1. H

8 Adatok a pusztai ölyv (Buteo rufinus) közötti hortobágyi előfordulásához Dr. Kovács Gábor Hortobágyi Nemzeti Park A szerző 16 év 232 megfigyelési adata alapján foglalkozik tanulmányában a pusztai ölyvvel. Munkájában utal az és közötti hét évtized hortobágyi adataira, főként Szomjas G. és Sterbetz I. közleményei alapján. A tanulmányban ismerteti a faj évszakos mozgalmait (vonulás, átnyaralás, telelés), táplálkozásra, viselkedésre vonatkozó megfigyeléseit. Becslése szerint a Hortobágyon 1987-ig évi 10-12, 1988-tól viszont már évi példány tartózkodott, főként a nyár végi,kora őszi két hónapban. Viszonylag új jelenség a tavasztól őszig tartó huzamos időzésük, mely 1990-ben és 1991-ben fordultelő. A fiatal egyedek aránya a 10-20%-ot nem haladja meg. A két színváltozat közül (öreg madarak) a világos változat a gyakoribb (80-85%) a vörössel szemben. Adatait táblázatos összesítés formájában közli. A pusztai ölyv havi megoszlását külön is bemutatja. 48