E X P E R I E N C E S ON T H E R E P A T R I A T I O N OF A R T I F I C I A L L Y R E A R E D G R E A T B U S T A R D S (OTIS T . T A R D A L . 1758) IN Dr. T. Fodor-F.
HUNGARY Pálnik
-Dr.
I. Sterbetz
Introduction Artificial rearing of the great bustard is a hard zootechnical task solved by long-continued experimentation. The question has plentiful literature and its traditions seem to be the oldest in Hungary (Chernél, 1904). The experiments initially conducted for amusement as traced back to the last Century have been developed in the Budapest Zoo in the period from 1907 to 1920 to a zoo practice having proved correct in its theses up to the present, and since 1958 the classical methodics have been continuously updated by Fodor. Since 1920, experiments have been conducted with success in a num ber of other European zoological gardens. A comprehensive review thereof is to be found in summarizing works by Heinroth (1928), Moody (1932), Gewalt (1966), Luckschanderl (1968), Radu (1969), Fodor-Nagy-Sterbetz (1971) and König (1979). As long as the experimentation only served zoo purposes, merely problems of hatching, rearing, feeding and hygiene have been studied. Since, however, the great bustard issue has become a problem of international nature conser vation, it is the repatriation to nature of birds reared in captivity, andthereby strengthening of the wild living populations that have become the targets.
Repatriation experiments abroad Threads of the repatriation of the great bustard precede by far the tradi tions of artificial rearing. Already at about 1628 to 1630, such experiments have been carried out when Wallenstein attempted to settle in Mecklenburg great bustards originating from Bohemia captured wild (Niethammer, 1963). In 1900 and 1901 birds imported from Spain, Roumania and Hungary were released in England unsuccessfully (Vadász L a p , 1901; Zoológiai Lapok, 1902). The first casual success was achieved by Rainer (1942). In Dobrudsha (Roumania) he had four great bustards hatched in 1919 by a turkey. These birds were living free for two years in a barn-yard. They began straying at their third year of age in a circle of ever larger radius and flew off in the sum mer of the third year. One of the males returned in December. This bird spent the winter in the safe environment of the barn-yard, then, in spring left for good and all. At present, repatriation of saved great bustards is carried out on farms in the German Democratic Republic. In the last ten years, young birds have been regularly placed out in the first autumn of their life (Prill, 1969; Dorn busch, 1976). In spite of the high rate of mortality in the first year the results 5 Aquila 1981.
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are considered satisfactory and the methodics based on drastic repatria tion entailing sacrifice but leading to quick results has been rendered systematic. Experiments in Poland are based on the so-called "microevolution" principle. The method consists in closed space management with several variations. It is aimed to develop a population transformed in its etiological and ecological characteristics suitably adapting itself to the conditions of changed habitats. The experiments are conducted by the Institute for Applied Zoology of the Academy of Agriculture of Poznan on the great bustard rear ing farm at Siemianicze founded in 1974 (Graczyh, 1975, 1976; Graczyk— Bereszynszki — Michocki, 1979). No repatriation result has been achieved as yet with the birds reared here. In England, experiments are carried out to study the closed space man agement and reproduction of great bustards originating from the Ibérián penin sula (verbal information by N. Collar). To the authors' knowledge, in future, strengthening of the Otis t. tarda population is envisaged in Czechoslovakia, Bulgária, Spain and Kazahstan using repatriation.
Experiences oí repatriation in Hungary In Hungary it is firstly intended to improve by the repatriation programme the structure and genetic state of wild great bustard populations deteriorated in their qualitative conditions. The problem was partly due to the hunting damage of earlier decades. Initially, it has impaired the populations in quantity, later on, due to one-sided cock shooting it led to an extreme worsening of the sex ratio. At present, the hunting of great bustards being prohibited it is the damage due to cultural practices that has driven the success of reproduction to a minimum levél, and thus the populations have grown old. Therefore, the replacement should be artificially promoted, too. The first phase of work, hatching and rearing have been solved and have traditions by now. A t the same time, the possibilities of the final aim, continuous repatriation, are scarcely known as yet. Turning the artificially reared great bustards wild again is highly circumstantial for two reasons. One of the difficulties is the well-known connection evolving between great bustard chicks and their tenders that develops very soon and is almost insolvable, the other is the stress effect arising on the occasion of return to the free environment. Earlier experiments performed with birds reared under zoo conditions offered pessimistic experiences. On the other hand, the authors' investigation launched in the spacious environ ment of their great bustard experiment Station operated since two years seem promising. Repatriation can be attempted using three kinds of Solution: drastic repatriation of young birds possibly reared at the cost of little human relations; with birds maintained on a spacious living-space having no intercourse with man beyond what is strictly necessary, waiting that sooner or later they voluntarily leave their enclosed habitat; - by the continued breeding of birds kept in captivity and having grown 66
tarne, whose progeny is being reared exempt from man. Thissecondgeneration is going to be released. Authors' experiences relating to these three kinds of methods ai*e as fol lows. Drastic repatriation experiments In 1943 Sterbetz had great bustards hatched using turkeys at Nagyszénás in county Békés. He attempted to release three chicks at ten weeks of age on the habitat of wild great bustards. He repeated the attempt on three occasions in two-day intervals each but in all three instances the birds were flying back immediately to their rearing place to be found next to a group of agricultural buildings. Finally, these birds had to be transported to the zoo. From 1958 on, the Bird Section of the Budapest Zoo organized the saving of endangered great bustard nests. This work was mainly based by Fodor on hunting associations. The Hunting Association of Dévaványa in Eastern Hungary was the most interested in it since a great bustard population of some 300 to 350 birds were living onits area. Latter is an ideal environment for the great bustard. Pheasant (Phasianus colchicus) eggs were hatched by brood-hens on the pheasant rearing farm of the Hunting Association, great bustard eggs mown out were treated the same way. In 1965, 14 great bustard chicks hatched out here, of these eleven were raised. On August 28, attempts were made to forcefully repatriate birds at 90 days of age. The first attempt was made in the afternoon hours. The great bustards driven out in front of the p h e a s a n t farm were unwilling to leave. They sat down and emitted their characteristic piping-crying voice. Next day, they were joined to an extensively managed flock of turkeys. The great bustards made timid approaches keeping safe distance to the turkeys of similar age who received the foreign birds. Early in September five of the eleven great bustards perished due to a disease ("black head") contracted from the turkeys. A t the same time, this infection did not kill the turkeys. Evidently, a lower-rate infection stress took place that the non-resistant great bustards could not withstand anymore. The six great bustards having survived were taken back to the pheasant farm. After two weeks of care and maintenance the ringed birds were trans ported in a cart to 10 km distance where a number of wild great bustards were regularly staying. On the flat steppe area the animals were released, then the tenders quickly left. The great bustards left behind observed the departing persons while standing on the spot. The cart returned to the pheas ant farm after one hour and a half. B y that time, three of the released birds were W a l k i n g n e a r the fencing. The C a r r i o n of one of the other three was found on September 30 in about one week's state, at 4 km distance from the site of release. Another bird joined a foreign person who captured it. Merely one single bird disappeared without leaving a trace whose successful repatriation may be presumed. The birds having returned to the pheasant farm had to be taken to the zoo.
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Experiences of voluntary repatriation I n 1940, nine great b u s t a r d chicks h a t c h e d b y a brood-hen a n d reared at the house were kept b y Sterbetz on a n enclosed area o f 3 h a extension s o w n t o lucerne at K o n d o r o s (county Békés, H u n g a r y ) . F r o m t h e i r 28 days o f age on, the birds were d r i v e n out b y their tender t o the neighbouring fields a n d pastures. F r o m this t i m e onwards, t h e y were r e - a d m i t t e d t o the enclosed rearing space o n l y for night. F r o m t h e i r nine weeks o f age o n , the birds left the sleeping-place a n d were s t r a y i n g b y themselves u n t i l evening. T h e y spent the w i n t e r on the enclosed area b u t c o n t i n u e d s t r a y i n g d u r i n g the w i n t e r , too. N e x t year i n M a r c h t h e y f i n a l l y left i n flocks. T h i s h a l f - w i l d great bus t a r d flock c o u l d be r e g u l a r l y observed t h a t y e a r i n s p r i n g a n d early s u m m e r , at about 7 to 8 k m distance f r o m t h e i r enclosed place o f management. T h e y were a w a i t i n g m a n to 50 to 60 m , horse-drawn vehicle still closer. L a t e r o n , their Observation was hindered b y the r u n - u p s u m m e r vegetation. A t the t i m e the a u t u m n great b u s t a r d flocks were förmed, the w i l d l i v i n g birds a n d those set out whose r i n g i n g was not possible as yet at t h a t t i m e , c o u l d not be d i s t i n g u i s h e d a n y m o r e . There were no news o f perished or c a p t u r e d great bustards, thus p r e s u m a b l y the r e p a t r i a t i o n ended w i t h success. I t s h o u l d be stressed t h a t this e x p e r i m e n t has been carried out at the h a b i t a t of a w i l d p o p u l a t i o n o f some 500 birds where even at the t i m e the c a p t i v i t y b i r d s were s t r a y i n g there was regulär occasion for connections w i t h the w i l d birds. I n 1975, the L a n d s c a p e C o n s e r v a t i o n D i s t r i c t at Dévaványa i n E a s t e r n H u n g a r y has been established i n v i e w o f experiments on the open-air protec t i o n o f the great b u s t a r d . T h e preserve is o f 3433 h a extension, to 5 3 % w i t h a b i o t o p of steppe character (Sterbetz 1977). I n 1980, the preserve is o w n e d b y the N a t i o n a l E n v i r o n m e n t a n d N a t u r e C o n s e r v a t i o n Office, a n d f r o m 1981 on, management w i l l be i n compliance w i t h the aspeets o f great b u s t a r d protection. O n the area there are fields o f poor q u a l i t y suitable o n l y for exten sive management. A great b u s t a r d p r o t e c t i o n Station has been b u i l t i n the steppe zone in 1978 where the authors i n t e n d t o have the great b u s t a r d eggs s a v e d f r o m damages due to c u l t u r a l practices, hatched. O n the basis o f earlier experience, y e a r l y some 100 eggs are r e c k o n e d w i t h here. T h e Station s t a r t e d f u n c t i o n i n g i n a u t u m n 1978. T h e technological e q u i p m e n t , tenders a n d researchers w i l l be a c c o m o d a t e d i n its three b u i l d i n g s . T r e a t m e n t w i l l be p r o v i d e d b y three animál tenders under guidance o f a t e c h n i c i a n . Scien t i f i c w o r k w i l l be managed b y the O r n i t h o l o g i e a l Institute. L a t e i n s u m m e r the great b u s t a r d chicks reared on the f a r m w i l l be set out t o a 200 X 300 m (6 ha) enclosed area of forest steppe character. I n N o v e m b e r 1978, 15 one-to three-year-old great bustards, o r i g i n a t i n g f r o m a zoo, w i t h a m p u t a t e d wings have been settled here. I n A u g u s t 1979, 55 birds, 90 days o l d , hatched a n d reared already at the f a r m have been placed w i t h t h e m . These birds h a d o n l y their w i n g feathers cut off a n d on the occasion o f their first m o u l t i n g regained their f l y i n g a b i l i t y . W i t h the new feathers developed these birds were f l y i n g about more a n d more frequently. A t first, the f l y i n g trials occurred o n l y inside the fencing then successive a r b i t r a r y l e a v i n g was observed. Observations of the resettling: — on the 15th J a n u a r y 1980, one b i r d has left; 68
Figure
13. Great Bustard Experiment Station at Dévaványa. 13. ábra. A dévaványai túzokkísérleti állomás
(Fotó: Dr. Sterbetz I.)
Figure
14. One-year
old great bustard cock in free environment the Great Bustard Experiment
photographed on llth June 1980. The bird has voluntarily Station to the habitat of wild great bustards
repatriated
from
— on the 20th J a n u a r y , one more flew a w a y , its carcase t o r n up b y a fox ( Vulpes vulpes) was f o u n d n e x t d a y i n the n e i g h b o u r h o o d of the f a r m ; — i n the course of J a n u a r y i t occurred several times t h a t some birds flew out a n d were w a l k i n g about near the farm ; part o f t h e m returned v o l u n t a r i l y , some were d r i v e n back b y the tenders; — on the lOth F e b r u a r y one more b i r d left the f a r m for g o o d ; — on the 7th M a y one b i r d flew off; — on the lOth M a y , t e n great bustards flew off i n closed flock at once; of these, one returned the same d a y , three others only after a few days, the remaining s i x departed for good a n d a l l ; — on the 2 n d J u l y one b i r d t o o k cover on a pasture 2 k m a w a y from the f a r m ; from its nearing tender it took flight again a n d disappeared i n the direction o f a k n o w n r u t t i n g site. — on the 9th J u l y t w o birds left the f a r m . A t the same t i m e , the game warden M. Lánci n o t i c e d at 3 k m distance from the f a r m , on a short-grass alkaline pasture three r i n g e d great bustards (consequently coming from the farm) i n the Company of four w i l d great bustards! T h i s was the first occasion when the m i x i n g o f reared a n d w i l d birds has been verified at Dévaványa; — on the 1 I t h J u l y a p h o t o was t a k e n b y Sterbetz of a r i n g e d great b u s t a r d at 2 k m distance from the great b u s t a r d f a r m ; — as o f J u n e , there is a constant f l u c t u a t i o n i n the n u m b e r of i n t a c t p l u m aged, one-year-old birds. B i r d s reared h a l f - w i l d are leaving a n d coming each d a y . T h e n u m b e r o f birds considered t o have f inally departed comes t o 62 according to the state recorded on the I t h Sept. 1981. A l l of t h e m are one-year-old birds h a t c h e d i n s p r i n g 1979. A c c o r d i n g t o a n Information ob t a i n e d meanwhile, the several m o n t h s ' remains o f a r i n g e d great b u s t a r d o r i g i n a t i n g from the great b u s t a r d f a r m has been f o u n d at some 4 k m distance f r o m the f a r m . I n the p e r i o d f r o m September t o N o v e m b e r 1979, the great bustards reared on the 6 h a enclosed area were s h o w i n g h i g h l y restless behaviour. T h e y were searching for the p o s s i b i l i t y o f getting out t h a t was s t i l l impossible at t h a t t i m e due to the cut off w i n g feathers. Three birds suffered fractures of legs a n d wings d u r i n g this restless period. T w o o f t h e m were healed. T h i s state ceased w i t h the onset of winter. T h e flyings off were a l w a y s accompanied b y adverse weather periods. T h e great bustards were leaving at the t i m e of sunspot a c t i v i t y , strong w i n d , sudden change i n atmospheric pressure, "break t h r o u g h on the f r o n t " . T h e l a s t i n g restlessness observed i n a u t u m n is certainly i n correlation w i t h the f o r m a t i o n o f w i n t e r i n g flocks o f w i l d great bustards. I t cannot be disregarded either t h a t d u r i n g this p e r i o d w i l d great bustards l i v i n g i n the n e i g h b o u r h o o d frequently approached the f a r m , thus the birds i n c a p t i v i t y could regularly see t h e i r companions. T h i s is going to be g r a d u a l l y p r o m o t e d b y rape (Brassica napus) sown t o the v i c i n i t y o f the f a r m , this c r o p b e i n g a h i g h l y favoured w i n t e r feed for the great b u s t a r d . Repatriation of great bustards originating from the continued breeding of captivity birds I n experiments c o n d u c t e d so far neither hens older t h a n four years n o r five t o s i x years o l d cocks have been a v a i l a b l e t h a t w o u l d have m u l t i p l i e d i n a suitable spacious e n v i r o n m e n t . T h e conditions a n d ideal b i o t o p o f 71
the great bustard farm at Dévaványa render it probable that reproduction will be successful. In the zoos at Duisburg, Budapest and West-Berlin this zootechnical problem has been solved in considerably more adverse envi ronment (Fodor, in: Fodor — Nagy — Sterbetz, 1971).
Conclusions Considering the experiences obtained so far and the possibilities of the nature conservation area having become the property of the Nature Conser vation Office the repatriation plans of the future are determined in Hungary by the following aspeets: 1. Under the conditions at Dévaványa foreeful setting out is justified only in cases necessitated by over-population of the farm. Setting out is advisable only from the spring of next year on, with regard to the critical winter season. Initial days of the period of reproduction seem the safest when the winter flocks of great bustards disintegrate also in the free environment and the territorial activity is generally increased. 2. Success of the voluntary repatriation has been verified. In all probability, this method is promising the becoming independent of considerable part of the birds in half-wild management. Presumably, several birds will not take the opportunity and will remain tarne for good and all. A drawback of the method is that the experiences obtained from both man and tame great bustards present ethological drawbacks for the great bustards resettling that way. 3. Management without human agency and voluntary repatriation of birds reproduced in captivity is promising the most reUable results. It has the difficulty of solving the no-man treatment, and the drawback is the breeding material sexually immature up to four to six years of age. 4. With all three methods, restriction to the minimum of the contact between man and the great bustard is higly desirable. 5. Hygiene of the great bustard farm is of outstandingimportance. Systematic disinfection of the tender as well as sterile feed, require the most careful discipline. The great bustards should be possibly isolated from rodents and birds. 6. External conditions of repatriation are, on theonehand, optimum biotop, on the other, presence there of a wild great bustard population of consider able number. On areas, where these two basic require ments are not provided, repatriation is surely hopeless. Every attempt intending to place the great bustard into an environment from where this bird has completely perished or where it has never lived, consequently lacking the possibility of adjoining wild companions, is fully senseless. From the aspect of nature conservation such experimentation merits eriticism also ethically. Authors' Address: T. Fodor Budapest F r a n k e l L e ó u . 20. H-1027
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F . Pálnik Dévaványa Túzoktelep H-5510
I. Sterbetz Budapest Fivér u . 4/a H-1131
References — Irodalom Chernél, I. (1904): M a d a r a k i n : B r e h m ' s T i e r l o b e n . B u d a p e s t . V I . p . 1 9 9 - 2 0 7 . Dornbusch, K. (1976): S c h u t z u n d F ö r d e r u n g d e r G r o s s t r a p p e ( O t i s t a r d a L . 1758) i n D D R . I I . N e m z e t k ö z i T ú z o k v é d e l m i S z i m p ó z i u m előadásai. S a r k a d r e m e t e , 1976. s z e p t . 2 8 - 3 0 . p. 6 3 - 6 5 . Fodor T.—Nagy L. —Sterbetz I. (1971): A túzok. B u d a p e s t , Mezőgazdasági K i a d ó , p. 1 - 1 5 5 . Geivalt, W. (1966): Über die H a l t u n g u n d Z u c h t der Grosstrappe. Zoologische Garten. 32. p . 2 5 5 - 3 2 7 . Qraczyk, R. (1975): F o r s c h u n g s p r o g r a m m u n d A u f g a b e n d e r A u f s t a l t z u r T r a p p e n z u c h t ( O t i s t a r d a ) i n P o l e n . R o c z n i k i A R W P o z n a n i u . R . 8 6 . O r n i t . S t o s . 8(9)10. P o z n a n , p. 1-14. Qraczyk, R. (1976): R e s e a r c h m e t h o d s o f t h e b r e e d i n g c e n t r e o f b u s t a r d ( O t i s t a r d a L . ) i n P o l a n d . I I . N e m z e t k ö z i T ú z o k v é d e l m i S z i m p ó z i u m előadásai. S a r k a d r e m e t e , 1976. s z e p t . 28 - 3 0 . p . 53 - 54. Qraczyk, R. — Bereszynszki, A.—Michocki, J. (1979): A d a p t o w a n i e sie d z i k i c h d r o p i (Otis t a r d a L . ) do w a r n u k o v o d o e l a n c h . R o c z n i k i A R w P o z n a n i u . Ornithologia Stosow a n a . 11. Heinroth, 0. u. M. (1928): D i e V ö g e l M i t t e l e u r o p a s . B d . I I I . p . 1 1 6 - 1 3 1 . König, O. (1979): D i e Grosstrappe (Otis tarda L . ) Gegenwartsprobleme u n d R e t t u n g m ö g l i c h k e i t e n . F o r s c h u n g s g e m e i n s c h a f t W i l h e l m m i e n e n b e r g k i a d v . W i e n , p . 1 — 10. Luckschanderl, L. (1968): Über A u f z u c h t v o n Grosstrappenckücken- D i e Gefiederte Welt. p. 183-187. Moody, A (1932): W a t e r f o w l a n d G a m e B i r d s i n C a p t i i t y . L o n d o n . Niethammer, Q. (1963): D i e E i n b ü r g e r u n g v o n Säugetiere u n d V ö g e l i n E u r o p a . H a m b u r g - B e r l i n , p . 272. Prill, G. (1969): A u f z u c h t u n d P f l e g e j u n g e r G r o s s t r a p p e i n S e r r h a n . D e r F a l k e . 10. p. 3 5 0 - 3 5 3 . Radu, D. (1969): D i e Aufzucht v o n Grosstrappen i n Zoologischen Garten Bukarest. F r e u n d e d e s K ö l l n e r Z O O . H . 2. 12. J h g . p . 5 9 - 6 4 . Rainer, R.-né (1942): T ú z o k o k r ó l . N i m r ó d V a d á s z ú j s á g . I I I . ( X X X . ) február 1. p . 53 - 5 4 . Sterbetz, I. (1977): T h e e n v i r o n m e n t o f the G r e a t B u s t a r d (Otis t a r d a L . ) i n H u n g a r y . A q u i l a , 1976. 83. p . 5 3 - 6 8 . — (1901): T ú z o k m e g h o n o s í t á s a A n g l i á b a n . V a d á s z L a p . V I I . 5. p . 2 5 3 . — (1902): T ú z o k h o n o s í t á s A n g l i á b a n . Z o o l ó g i a i L a p o k . I V . p . 2 0 7 .
Magyarországi tapasztalatok mesterségesen felnevelt túzokok (Otis t. tarda L . 1758) repatriációjárói Dr. Fodor Tamás—Pálnik
Ferenc — Dr. Sterbetz
István
Bevezetés
A t ú z o k mesterséges felnevelése hosszú kísérletezéssel m e g o l d o t t , nehéz z o o t e c h n i k a i f e l a d a t . A kérdés i r o d a l m a g a z d a g , és lehetséges, h o g y e p r o b l é m á n a k M a g y a r o r s z á g o n l e g r é g i b b e k a h a g y o m á n y a i (Chernél, 1904). A m ú l t század ó t a n y o m o n k ö v e t h e t ő , k e z d e t b e n h o b b i c é l ú kísérleteket 1907 — 1920 i d ő k ö z é b e n a b u d a p e s t i Z O O - b a n fejlesztették téziseiben m a is helytálló állatkerti g y a k o r l a t t á , és 1958 ó t a Fodor f o l y a m a t o s a n m o d e r nizálja a „klasszikus m e t o d i k á t . 1920 ó t a s z á m o s m á s e u r ó p a i állatkert is s i k e r r e l kísér l e t e z e t t . Á t t e k i n t ő ismertetésük Heinroth (1928), Moody (1932), Gewalt (1966), Luckschan derl ( 1 9 6 8 ) , Radu (1969), Fodor - Nagy-Sterbetz (1971) és König (1979) összefoglaló munkáiban találhatók. A m í g a kísérletezés c s a k állatkerti c é l o k a t szolgált, a d d i g m i n d ö s s z e a keltetés, a n e v e lés, a t a k a r m á n y o z á s és a higiénia p r o b l é m á i t vizsgálták. A m i ó t a a z o n b a n a t ú z o k k é r d é s n e m z e t k ö z i t e r m é s z e t v é d e l m i p r o b l é m á v á vált, a f o g s á g b a n n e v e l t p é l d á n y o k n a k a s z a b a d t e r m é s z e t b e t ö r t é n ő visszajuttatása és e z z e l a v a d o n élő p o p u l á c i ó k erősítése a c é l .
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R e p a t r i á c i ó s kísérletek k ü l f ö l d ö n
A t ú z o k r e p a t r i á c i ó j á n a k szálai m e s s z e m e g e l ő z i k a mesterséges nevelés h a g y o m á n y a i t . M á r 1628 — 1630 táján t ö r t é n t e k i l y e n kísérletek, a m i k o r Wallenstein C s e h o r s z á g b ó l szár m a z ó , v a d o n f o g o t t t ú z o k o k a t M e c k l e n b u r g b a p r ó b á l t áttelepíteni (Niethammer, 1963). A n g l i á b a n 1 9 0 0 . és 1 9 0 1 . é v b e n S p a n y o l o r s z á g b ó l , R o m á n i á b ó l és M a g y a r o r s z á g b ó l h o z a t o t t állatokat engedtek s z a b a d o n eredménytelenül (Vadász L a p , 1901; Zoológiai L a p o k , 1902). A z első, véletlen a d t a e r e d m é n y fíainer-től (1942) s z á r m a z i k . A r o m á n i a i D o b r u d zsában 1 9 1 9 - b e n p u l y k á v a l k e l t e t e t t k i i t t a szerző n é g y t ú z o k o t . E z e k a m a d a r a k két é v i g s z a b a d o n éltek e g y b a r o m f i u d v a r b a n . H a r m a d é v e s k o r u k b a n k e z d t e k e g y r e n a g y o b b sugarú k ö r b e n k ó b o r o l n i , és a h a r m a d i k é v n y a r á n elrepültek. A z e g y i k 9 d e c e m b e r b e n visszatért. E z a p é l d á n y a b a r o m f i u d v a r b i z t o n s á g o s k ö r n y e z e t é b e n t ö l t ö t t e a t e l e t , m a j d tavasszal végleg távozott. J e l e n l e g a N é m e t D e m o k r a t i k u s Köztársaság üzemi s z i n t e n foglalkozik a m e n t e t t túzo k o k r e p a t r i á c i ó j á v a l . A z u t ó b b i tíz é v b e n m á r r e n d s z e r e s e n h e l y e z n e k k i életük első őszén f i a t a l p é l d á n y o k a t (Prill, 1 9 6 9 ; Dornbusch, 1976). A z e r e d m é n y e k e t a z első é v i m a g a s m o r t a l i t á s ellenére is k i e l é g í t ő n e k ítélik m e g , és rendszeresítették e z t a z e r ő s z a k o s v i s s z a I elépítésen a l a p u l ó , á l d o z a t o s , d e g y o r s e r e d m é n y e k r e v e z e t ő m e t o d i k á t . A l e n g y e l kísérletek a z ún. „ m i k r o e v o l ú c i ó s " e l v e n a l a p u l n a k . A m ó d s z e r z á r t téri t a r tás t ö b b f é l e v a r i á c i ó b a n . Célja e g y o l y a n e t o l ó g i a i és ö k o l ó g i a i t u l a j d o n s á g a i b a n átalakí t o t t p o p u l á c i ó kifejlesztése, a m e l y a m e g v á l t o z o t t é l ő h e l y e k a d o t t s á g a i h o z m e g f e l e l ő e n a l k a l m a z k o d i k . A kísérletet a P o z n a n i M e z ő g a z d a s á g i A k a d é m i a A l k a l m a z o t t Á l l a t t a n i I n t é z e t e v é g z i a z 1 9 7 4 - b e n a l a p í t o t t , S i e m i a n i c z e i T ú z o k n e v e l ő T e l e p e n (Graczyk, 1975, 1976; Graczyk — Bereszynszki — Michocki, 1979). E z e k k e l a z i t t n e v e l t állatokkal r e p a t r i ációs eredmény m é g n e m a d ó d o t t . A n g l i á b a n a z Ibériai-félszigetről s z á r m a z ó t ú z o k o k z á r t téri t a r t á s a és t o v á b b s z a p o r í t á s a é r d e k é b e n t ö r t é n i k kísérletezés (Gollar, N. s z ó b e l i t á j é k o z t a t á s a ) . T u d o m á s u n k s z e r i n t a j ö v ő b e n C s e h s z l o v á k i á b a n , B u l g á r i á b a n , S p a n y o l o r s z á g b a n és K a z a h s z t á n b a n t e r v e z i k a z O t i s t. t a r d a p o p u l á c i ó i n a k repatriációs ú t o n t ö r t é n ő m e g erősítését.
Repatriációs tapasztalatok Magyarországon
M a g y a r o r s z á g o n a repatriációs p r o g r a m m a l e l s ő s o r b a n a m i n ő s é g i a d o t t s á g a i b a n l e r o m l o t t , v a d t ú z o k p o p u l á c i ó k s t r u k t ú r á j á n és g e n e t i k a i á l l a p o t á n szeretnénk j a v í t a n i . A p r o b l é m á t egyrészt a k o r á b b i é v t i z e d e k v a d á s z a t i károsítása o k o z t a . E z k e z d e t b e n a p o p u l á c i ó k a t m e n n y i s é g é b e n k á r o s í t o t t a , k é s ő b b a z e g y o l d a l ú k a k a s l ö v é s m i a t t n a g y o n szélső séges i v a r a r a n y r o m l á s h o z v e z e t e t t . A j e l e n b e n , a m i k o r a t ú z o k v a d á s z a t a m á r t i l o s , a z a g r o t e c h n i k a i k á r o s í t á s a s z a p o r o d á s sikerét szorítja m i n i m á l i s s z i n t r e , és í g y f o l y a m a t o s a n e l ö r e g e d n e k a p o p u l á c i ó k . E z é r t szükséges a z u t á n p ó t l á s t mesterségesen is elősegíteni. A m u n k a első fázisa, a keltetés és a n e v e l é s m a m á r t r a d í c i ó k k a l r e n d e l k e z ő é n m e g o l d o t t . U g y a n a k k o r a l i g ismerjük m é g a v é g c é l , a f o l y a m a t o s r e p a t r i á c i ó lehetőségeit. A mesterségesen f e l n e v e l t t ú z o k o k v i s s z a v a d í t á s a k é t o k b ó l r e n d k í v ü l k ö r ü l m é n y e s . A z e g y i k k ö z i s m e r t nehézség a t ú z o k c s i b é k és g o n d o z ó i k k ö z ö t t n a g y o n h a m a r kialakuló, és m a j d n e m f e l o l d h a t a t l a n k a p c s o l a t , a m á s i k a s z a b a d k ö r n y e z e t b e t ö r t é n ő visszatérés a l k a l m á v a l b e k ö v e t k e z ő stresszhatás. K o r á b b a n a z állatkerti k ö r ü l m é n y e k k ö z ö t t n e v e l k e d e t t m a d a r a k k a l v é g z e t t kísérletek p e s s z i m i s t a t a p a s z t a l a t o k a t s z o l g á l t a t t a k . E z z e l s z e m b e n p e r s p e k t i v i k u s a b b n a k ígérkezik a k é t é v e ü z e m e l ő túzokkísérleti á l l o m á s u n k n a k tágas k ö r n y e z e t é b e n b e i n d í t o t t v i z s g á l a t u n k . A repatriációt háromféle megoldással lehet megkísérelni: — f i a t a l , lehetőleg k e v é s e m b e r i k a p c s o l a t árán f e l n e v e l t p é l d á n y o k e r ő s z a k o s v i s s z a telepítésével; — t á g a s élettérben t a r t o t t , e m b e r r e l c s a k a l e g s z ü k s é g e s e b b m é r t é k b e n érintkező pél d á n y o k k a l , a r r a v á r v a , h o g y e z e k e l ő b b - u t ó b b ö n k é n t h a g y j á k e l elkerített é l ő h e l y ü k e t ; — fogságban t a r t o t t , megszelídült p é l d á n y o k továbbtenyésztésével, a m e l y e k szaporu l a t a m á r e m b e r m e n t e s e n n e v e l k e d i k . E m á s o d i k g e n e r á c i ó kerül m a j d s z a b a d o n b o c s á tásra. E háromféle módszerrel k a p c s o l a t o s t a p a s z t a l a t a i n k a következők.
74
Erőszakolt
visszatelepítési
kísérletek
1 9 4 3 - b a n Sterbetz a B é k é s m e g y e i N a g y s z é n á s o n p u l y k á v a l k e l t e t e t t t ú z o k o k a t . 3 d b c s i b é t p r ó b á l t 10 h e t e s k o r b a n v a d t ú z o k o k é l ő h e l y é n k i b o c s á t a n i . K é t - k é t n a p o s i d ő k ö z ö k b e n h á r o m s z o r kísérelte m e g e z t , d e a m a d a r a k m i n d h á r o m e s e t b e n a z o n n a l v i s s z a repültek e g y m e z ő g a z d a s á g i é p ü l e t c s o p o r t k ö z e l é b e n l e v ő n e v e l ő h e l y ü k r e . E z e k e t a z álla t o k a t v é g ü l állatkertbe k e l l e t t szállítani. 1958-tól a B u d a p e s t i Á l l a t k e r t M a d á r o s z t á l y a s z e r v e z t e a v e s z é l y e z t e t e t t t ú z o k f é s z k e k m e n t é s é t . E z t a m u n k á t Fodor elsősorban v a d á s z t á r s a s á g o k r a a l a p o z t a . A l e g é r d e k e l t e b b v o l t e b b e n a k e l e t - m a g y a r o r s z á g i D é v a v á n y a i Vadásztársaság, a m e l y n e k területén k b . 300 — 350 e g y e d e t s z á m l á l ó t ú z o k p o p u l á c i ó élt. A terület a t ú z o k e s z m é n y i k ö r n y e z e t e . A vadásztársaság fácán- (Phasianvs colchicus) n e v e l ő telepén k o t l ó s t y ú k k a l keltették a f á c á n t o j á s t , u g y a n í g y k e z e l t é k a kikaszált t ú z o k t o j á s o k a t i s . 1 9 6 5 - b e n i t t 14 t ú z o k c s i b e k e l t k i , és e z e k b ő l 11-et sikerült f e l n e v e l n i . A u g u s z t u s 28-án 90 n a p o s k o r b a n p r ó bálták a m a d a r a k a t erőszakosan repatriálni. A z első p r ó b á l k o z á s a délutáni ó r á k b a n tör tént. A f á c á n t e l e p elé k i t e r e l t t ú z o k o k n e m v o l t a k h a j l a n d ó k e l t á v o n z i . L e ü l t e k és j e l legzetes fütyülő-síró h a n g j u k a t h a l l a t t á k . M á s n a p e x t e n z í v tartású p u l y k a c s a p a t h o z c s a t l a k o z t a t t á k ő k e t . A t ú z o k o k félénken, b i z t o n s á g o s t á v o l s á g o t t a r t v a közelítettek a hasonló korú pulykákhoz, a m e l y e k befogadták az idegen m a d a r a k a t . S z e p t e m b e r elején a l l t ú z o k b ó l 5 p é l d á n y a p u l y k á k t ó l k a p o t t b e t e g s é g ( „ b l a c k h e a d " ) m i a t t e l p u s z t u l t . A p u l y k á k k ö z ö t t u g y a n a k k o r ez a fertőzés n e m p u s z t í t o t t . N y i l v á n v a l ó a n a l a c s o n y a b b fertőzési terhelés t ö r t é n t , a m e l y e t a r e z i s z t e n c i a - m e n t e s t ú z o k m á r n e m b í r t k i . A m e g m a r a d t 6 t ú z o k o t e k k o r v i s s z a v i t t é k a fácántelepre. K é t h e t e s tartás u t á n a m e g g y ű rűzött m a d a r a k a t szekérrel 10 k m t á v o l s á g r a szállították, a h o l s z á m o s v a d t ú z o k is r e n d s z e r e s e n t a r t ó z k o d o t t . A sík s z t y e p p t e r ü l e t e n a z állatokat k i e n g e d t é k , m a j d a s z e m é l y e k g y o r s a n eltávoztak. A v i s s z a h a g y o t t túzokok egy h e l y b e n állva figyelték a távozókat. A k o c s i másfél ó r a m ú l t á n érkezett v i s s z a a fácántelepre. E k k o r r a m á r a s z a b a d o n b o c s á t o t t m a d a r a k b ó l h á r o m a kerítés m e l l e t t sétált. A m á s i k h á r o m k ö z ü l a z e g y i k hulláját k b . e g y h e t e s á l l a p o t b a n s z e p t e m b e r 30-án m e g t a l á l t á k , a k i b o c s á t á s h e l y é t ő l 4 k m távol s á g b a n . E g y m á s i k p é l d á n y i d e g e n e m b e r h e z c s a t l a k o z o t t , a k i a z t e l f o g t a . E g y e t l e n pél d á n y t ű n t c s a k e l n y o m t a l a n u l , a m e l y n e k s i k e r e s repatriációja is feltételezhető. A fácánt e l e p r e visszatért m a d a r a k a t állatkertbe k e l l e t t szállítani. Tapasztalatok
az önkéntes
repatriációról
Sterbetz 1 9 4 0 - b e n a k e l e t - m a g y a r o r s z á g i K o n d o r o s o n ( B é k é s m . ) k i l e n c , k o t l ó s t y ú k k a l k i k e l t e t e t t és h á z n á l n e v e l t t ú z o k c s i b é t t a r t o t t 3 h a n a g y s á g ú , lucernával b e v e t e t t , e l k e rített területen. A m a d a r a k a t 28 n a p o s k o r u k t ó l k e z d v e g o n d o z ó j u k n a p o n t a k i t e r e l t e a s z o m s z é d o s s z á n t ó f ö l d e k r e és legelőkre. E t t ő l k e z d v e c s a k éjszakára e n g e d t é k v i s s z a ő k e t a z elkerített n e v e l ő t é r b e . K i l e n c h e t e s k o r u k t ó l k e z d v e a m a d a r a k m á r m a g u k t ó l h a g y t á k e l a z a l v ó h e l y e t , és e s t i g ö n á l l ó a n k ó b o r o l t a k . A t e l e t a z elkerített területen töl t ö t t é k , d e télen át is f o l y a m a t o s v o l t a k ó b o r l á s u k . A k ö v e t k e z ő é v m á r c i u s á b a n c s a p a t o s a n v é g l e g e l t á v o z t a k . E z t a félvad t ú z o k c s a p a t o t a z o n a t a v a s z o n és n y á r k e z d e t é n r e n d s z e r e s e n m e g l e h e t e t t f i g y e l n i , z á r t téri tartási h e l y ü k t ő l 7 — 8 k m t á v o l s á g b a n . A z e m b e r t 50 — 6 0 m - r e b e v á r t á k , a l o v a s k o c s i t m é g k ö z e l e b b . A f e l m a g a s o d ó , nyári n ö v é n y z e t k é s ő b b lehetetlenné t e t t e m e g f i g y e l é s ü k e t . A z őszi t ú z o k c s a p a t o k kialakulása idején már n e m l e h e t e t t k ü l ö n b s é g e t t e n n i a v a d o n élő és a kitelepült p é l d á n y o k k ö z ö t t , a m e l y e k m e g g y ű r ű z é s é r e s a j n o s a k k o r m é g n e m v o l t lehetőség. E l h u l l o t t v a g y e l f o g o t t t ú z o k r ó l n e m érkezett hír, í g y v a l ó s z í n ű , h o g y s i k e r e s e n v é g z ő d ö t t a r e p a t r i á c i ó . H a n g s ú l y o z n u n k k e l l , h o g y ez a kísérlet e g y k b . 500 e g y e d e t s z á m l á l ó , v a d p o p u l á c i ó é l ő h e l y é n t ö r t é n t , a h o l m é g a fogsági p é l d á n y o k k ó b o r l á s a idején is r e n d s z e r e s a l k a l o m nyílt a v a d p é l d á n y o k k a l történő k a p c s o l a t r a . 1 9 7 5 - b e n a t ú z o k s z a b a d t é r i v é d e l m é n e k kísérletei é r d e k é b e n létesült a D é v a v á n y a i T á j v é d e l m i K ö r z e t K e l e t - M a g y a r o r s z á g o n . A v é d e t t terület kiterjedése 3433 h a , 5 3 % - b a n s z t y e p p jellegű b i o t ó p p a l (Sterbetz, 1977). A r e z e r v á t u m 1980 ó t a a z O r s z á g o s K ö r n y e zet- és T e r m é s z e t v é d e l m i H i v a t a l t u l a j d o n a , és o t t 1981-től a g a z d á l k o d á s a t ú z o k v é d e l e m s z e m p o n t j a i n a k megfelelően történik. A rezervátumban levő szántóföldek minősége rossz, és o t t c s a k e x t e n z í v g a z d á l k o d á s f o l y t a t h a t ó . A s z t y e p p z ó n á b a n é p ü l t fel 1 9 7 8 - b a n a t ú z o k v é d e l m i á l l o m á s u n k , a h o l a z a g r o t e c h n i k a i k á r o k elől m e n t e t t t ú z o k t o j á s o k a t szán d é k o z u n k a j ö v ő b e n k i k e l t e t n i . A k o r á b b i t a p a s z t a l a t o k alapján évi 100 d b k ö r ü l alakuló t o j á s m e n n y i s é g r e s z á m í t u n k i t t . A z á l l o m á s 1978 őszén k e z d t e m e g m ű k ö d é s é t . H á r o m é p ü l e t e a t e c h n o l ó g i a i b e r e n d e z é s e k n e k , a k e z e l ő k n e k és a k u t a t ó k n a k elhelyezését b i z t o sítja. A kezelést e g y t e c h n i k u s irányításával h á r o m á l l a t g o n d o z ó látja e l . A t u d o m á n y o s m u n k á r ó l a M a d á r t a n i I n t é z e t g o n d o s k o d i k . A t e l e p e n felnevelkedő t ú z o k c s i b é k n y á r
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v é g é n e g y e r d ő s s z t y e p p jellegű, 200 X 300 m - e s (6 h a ) b e k e r í t e t t területre l e s z n e k k i h e l y e z v e . I d e 1978 n o v e m b e r b e n 15 d b állatkertből s z á r m a z ó , a m p u t á l t s z á r n y ú , 1—3 é v e s t ú z o k o t t e l e p í t e t t ü n k . 1 9 7 9 . a u g u s z t u s b a n 55 d b — m á r a t e l e p e n k e l t e t e t t és n e v e l t 90 n a p o s p é l d á n y t h e l y e z t ü n k k i h o z z á j u k . E z e k n e k a m a d a r a k n a k c s a k a s z á r n y t o l l a i v o l t a k l e v á g v a , és első v e d l é s ü k a l k a l m á v a l v i s s z a n y e r t é k r ö p k é p e s s é g ü k e t . Ú j t o l l a z a t ú k kifejlődésével e z e k a m a d a r a k e g y r e g y a k r a b b a n r e p k e d t e k . A repülési p r ó b á k e l ő s z ö r c s a k a kerítésen belül t ö r t é n t e k , m a j d e g y m á s t k ö v e t ő , ö n k é n y e s t á v o z á s r a került s o r . A kitelepülések észlelései: — 1980. j a n u á r 15-ón e g y p é l d á n y t á v o z o t t ; — j a n u á r 20-án i s m é t kirepült e g y , e n n e k r ó k a ( V u l p e s v u l p e s ) által s z é t t é p e t t t e t e m é t másnap megtalálták a telep közelében; — j a n u á r f o l y a m á n t ö b b s z ö r e l ő f o r d u l t , h o g y e g y e s p é l d á n y o k kirepültek, és a t e l e p k ö z e l é b e n s é t á l g a t t a k ; e z e k e g y része ö n k é n t tért h a z a , e g y e s e k e t a z á l l a t g o n d o z ó k t e r e l tek vissza; — február 10-én ú j a b b m a d á r h a g y t a e l v é g l e g a t e l e p e t ; — m á j u s 7-én e g y p é l d á n y repült e l ; — m á j u s 10-én zárt c s a p a t b a n tíz t ú z o k r e p ü l t k i e g y s z e r r e ; k ö z ü l ü k e g y m é g a z n a p , a m á s i k h á r o m c s a k n a p o k m ú l v a tért h a z a , a t ö b b i h a t v é g é r v é n y e s e n t á v o l m a r a d t ; — július 2-án e g y p é l d á n y a t e l e p t ő l 2 k m - r e szállt le e g y l e g e l ő r e ; k ö z e l í t ő g o n d o z ó j a elől ú j b ó l felrepült és e g y k ö z i s m e r t d ü r g ő h e l y i r á n y á b a n t ű n t s z e m e l ő l ; — július 9-én két p é l d á n y h a g y t a e l a t e l e p e t . U g y a n a k k o r Lánci Mihály v a d ő r a t e l e p t ő l 3 k m - r e e g y r ö v i d f ű v ű s z i k e s l e g e l ő n 3 d b g y ű r ű v e l j e l ö l t ( t e h á t a telepről s z á r m a z ó ) t ú z o k o t f i g y e l t m e g 4 d b v a d t ú z o k t á r s a s á g á b a n ! E z a z első a l k a l o m , h o g y f e l n e v e l t és v a d m a d a r a k k e v e r e d é s e b e b i z o n y o s o d o t t D é v a v á n y á n ; — júlus 11-én a t ú z o k t e l e p t ő l 2 k m t á v o l s á g b a n Sterbetz e g y g y ű r ű v e l m e g j e l ö l t pél dányt fényképezett; — j ú n i u s t ó l k e z d v e a z é p tollazatú, e g y é v e s p é l d á n y o k k ö z ö t t á l l a n d ó a l é t s z á m i n g a d o z á s . N a p o n t a t á v o z n a k és é r k e z n e k a f é l v a d o n n e v e l t m a d a r a k . A v é g l e g e s n e k t e k i n t e t t t á v o l m a r a d ó k s z á m a 1 9 8 1 . s z e p t e m b e r - i á l l a p o t s z e r i n t 62 d b . V a l a m e n n y i 1979 t a v a B z á n k e l t e t e t t e g y é v e s p é l d á n y . I d ő k ö z b e n érkezett a hír, h o g y e g y g y ű r ű v e l j e l ö l t , a tú zoktelepről származó túzok t ö b b hónapos maradványát a túzokteleptől m i n t e g y 4 k m távolságban megtalálták. 1979 s z e p t e m b e r é t ő l k e z d v e n o v e m b e r v é g é i g a 6 h a - o s b e k e r í t e t t területen t a r t o t t t ú z o k o k r e n d k í v ü l n y u g t a l a n u l v i s e l k e d t e k . B u j k á l v a keresték a kijutás l e h e t ő s é g é t , a m e l y a k k o r m é g l e v á g o t t s z á r n y t o l l a i k m i a t t n e m v o l t lehetséges. H á r o m p é l d á n y e n y u g t a l a n p e r i ó d u s b a n láb- és s z á r n y t ö r é s t s z e n v e d e t t . K ö z ü l ü k k e t t ő t sikerült m e g g y ó g y í t a n i . E z a z á l l a p o t a tél b e á l l t á v a l m e g s z ű n t . A kirepüléseket m i n d e n k o r k e l l e m e t l e n időjárási p e r i ó d u s o k kísérték. N a p f o l t t e v é k e n y s é g , e r ő s szél, h i r t e l e n l é g n y o m á s v á l t o z á s , „ f r o n t b e t ö r é s e k " idején t á v o z t a k a t ú z o k o k . A z ősszel észlelt, h u z a m o s n y u g t a l a n s á g b i z o n y á r a a v a d t ú z o k o k telelő c s a p a t a i n a k kialakulásával h o z h a t ó ö s s z e f ü g g é s b e . A z s e m h a g y h a t ó f i g y e l m e n k í v ü l , h o g y e b b e n a z i d ő s z a k b a n a k ö z e l b e n elő v a d t ú z o k o k is g y a k r a n m e g k ö z e l í t e t t é k a t e l e p e t , í g y a fogsági p é l d á n y o k r e n d s z e r e s e n l á t h a t t á k v a d társaikat. E z t a k ö r ü l m é n y t a j ö v ő b e n a t e l e p k ö z e l é b e n v e t e t t r e p c é v e l (Brassica napus) — a t ú z o k k e d v e l t téli t á p l á l é k n ö v é n y é v e l — f o k o z a t o s a n i g y e k s z ü n k m a j d e l ő s e g í t e n i . Fogsági
példányok
továbbtenyésztéséből
származó
egyedek
repatriációja
E d d i g i kísérleteink s o r á n m é g n e m r e n d e l k e z t ü n k o l y a n , n é g y é v n é l i d ő s e b b t y ú k o k k a l és 5 — 6 é v e s k a k a s o k k a l , a m e l y e k megfelelő tágas k ö r n y e z e t ü k b e n s z a p o r o d h a t t a k v o l n a . A d ó v a v á n y a i t ú z o k t e l e p t á g a s a d o t t s á g a i és e s z m é n y i b i o t ó p j a valószínűsítik, h o g y a szaporítás sikerülni f o g . A d u i s b u r g i , a b u d a p e s t i és a n y u g a t - b e r l i n i á l l a t k e r t e k b e n e z t a nehéz z o o t e c h n i k a i kérdést s o k k a l k e d v e z ő t l e n e b b k ö r n y e z e t b e n is sikerült m á r m e g o l d a n i (Fodor, i n : Fodor-Nagy-Sterbetz, 1971).
Következtetések
A z e d d i g i t a p a s z t a l a t o k és a t e r m é s z e t v é d e l m i t u l a j d o n b a k e r ü l t r e z e r v á t u m lehetősé geit mérlegelve a következő s z e m p o n t o k határozzák m e g a j ö v ő b e n i m a g y a r repatriációs terveket. 1. A d ó v a v á n y a i a d o t t s á g o k m e l l e t t a z e r ő s z a k o l t k i h e l y e z é s c s a k o l y a n e s e t b e n i n d o k o l t , h a a t e l e p túlnópesedettsége e z t k é n y s z e r b ő l m e g k í v á n j a . A kihelyezés a k r i t i k u s téli i d ő s z a k r a v a l ó t e k i n t e t t e l c s a k a k ö v e t k e z ő é v t a v a s z á t ó l célszerű. L e g b i z t o s a b b n a k
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látszik a s z a p o r o d á s i d ő s z a k á n a k k e z d e t i n a p j a i , a m i k o r a téli t ú z o k c s a p a t o k a s z a b a d k ö r n y e z e t b e n is f e l b o m l a n a k és a territoriális a k t i v i t á s általánosan f o k o z o t t . 2. A z ö n k é n t e s r e p a t r i á c i ó s i k e r e b e b i z o n y o s o d o t t . E z a m ó d s z e r a j ö v ő b e n m i n d e n b i z o n n y a l a f é l v a d o n t a r t o t t m a d a r a k j e l e n t ő s h á n y a d á n a k önállósulását ígéri m a j d . V a l ó s z í n ű , h o g y s z á m o s m a d á r m a g á t ó l n e m f o g élni e z z e l a lehetőséggel és v é g é r v é n y e s e n szelíd m a r a d . E m ó d s z e r h á t r á n y a m é g , h o g y a z e m b e r t ő l és a szelíd t ú z o k o k t ó l k a p o t t t a p a s z t a l a t o k e t o l ó g i a i h á t r á n y o k a t j e l e n t e n e k a z i l y m ó d o n kitelepülő t ú z o k o k s z á m á r a . 3. A f o g s á g b a n s z a p o r í t o t t e g y e d e k u t ó d a i n a k e m b e r m e n t e s tartása és ö n k é n y e s rep a t r i á c i ó j a ígéri a l e g b i z t o s a b b e r e d m é n y e k e t . E n n e k nehézsége a z e m b e r m e n t e s kezelés m e g o l d á s a , h á t r á n y a a 4 — 6 é v e s k o r i g ivaréretlen t e n y é s z a n y a g . 4. M i n d h á r o m m ó d s z e r n é l a z e m b e r és a t ú z o k k a p c s o l a t á n a k m i n i m u m r a szorítása h a n g súlyozottan kívánatos. 5. R e n d k í v ü l n a g y j e l e n t ő s é g e v a n a t ú z o k t e l e p higiéniájának. A g o n d o z ó k r e n d s z e r e s fertőtlenítése és a s t e r i l t á p l á l é k a l e g g o n d o s a b b f e g y e l m e t k í v á n j a m e g . R á g c s á l ó k és m a d a r a k elől a t ú z o k o k a t lehetőség s z e r i n t e l k e l l k ü l ö n í t e n i . 6. A r e p a t r i á c i ó külső feltételei e g y r é s z t a z o p t i m á l i s b i o t ó p , másrészt o t t e g y n a g y o b b l é t s z á m ú , v a d t ú z o k p o p u l á c i ó jelenléte. O l y a n területeken, a h o l ez a két a l a p k ö v e t e l m é n y n i n c s b i z t o s í t v a , a r e p a t r i á c i ó r e m é n y t e l e n . É r t e l m e t l e n m i n d e n o l y a n kísérletezés, a m e l y a t ú z o k o t o l y a n k ö r n y e z e t b e k í v á n j a h e l y e z n i , a h o n n a n ez a m a d á r m á r m a r a d é k t a l a n u l k i p u s z t u l t v a g y s o h a s e m élt, í g y n i n c s m e g a v a d t á r s a k h o z c s a t l a k o z á s l e h e t ő s é g e . T e r m é s z e t v é d e l m i s z e m p o n t b ó l a z i l y e n kísérletezés e t i k a i l a g is kritikát é r d e m e l .
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