BEHAVIOUR OF HAND REARED AND WILD RED-LEGGED PARTRIDGE (Alectoris rufa) USED IN REPOPULATIONS PÉREZ, J.A.; ALONSO, M.E.; GAUDIOSO, V.; DÍEZ, C.; BARTOLOMÉ, D. Dpto. Producción Animal II, Facultad de Veterinaria de León España. E.mail: XXXVIII International Congress of the ISAE (HELSINKI, INTRODUCTION. Release of animals from game farms is commonly used to increase the scarce production of wild populations of red-legged partridges trying to brake the progressive restriction of the distribution area of the species in Spain. Production systems and handling carried out in game farms are highly technical and intensified producing changes in behaviour patterns characteristic of wild animals rebounding in their reproductive cycle (GAUDIOSO et als., 2002). All of this, together with the taming processes the birds suffer, originate some long term physiologic and ethologic modifications that, consequently, develop serious adaptation and integration in the wild problems (LUCIO, 1992). OBJETIVES. We aims to evaluate the behaviour of game farm birds when they are released in natural environment, comparing their behaviour with wild red-legged partridges one. We studied some eco-ethological interesting parameters for the repopulation: dispersion from the release point, home range and their covey integration capacity. MATERIAL AND METHODS. STUDY AREA: The study was carried out in a property of 308 hectares located in Valladolid county, in the Autonomous Community of Castilla and León (Spain), with a stable population of wild red-legged partridge (Alectoris rufa) and an appropriate habitat for the survival of the species. ANIMALS: Thirty six 2-3 months old chickens of red-legged partridges coming from a commercial game farm and twelve wild animals of the same age captured in the study area at the beginning of the experimental protocol were used. All partridges were equipped with Biotrack  radio transmitter necklaces, with a weight of 9.8 grams and minimum autonomy of 11 months. In the right leg were placed a metallic numbered ring (Photo 1). RELEASE METHOD: Acclimatization cages of 4 m2 (2 m long x 2 m wide x 1 m high) placed directly on the land, with growth of vegetation characteristic of the environment, with a drinking trough of constant level and dispersed seeds of cereals on the floor. The release consisted on the opening of the cages door in the dawn, so that the animals could left to the sun rise, avoiding any manipulation that forced the exit. The animals were introduced in each cage, in groups of 2 birds, 2 days before their release (Photo 2). PARTRIDGES LOCALIZATION: Once released it was carried out individual daily birds localization, five days per week during the first two weeks and two days per week after this moment, using a receiving unit Yaesu  with directional antenna (GORTÁZAR et al., 1997) (Photo 3). DATA ANALYISIS: The computer program Ranges V© was used to calculate animals dispersion after release (KENWARD et al., 1996). To carry out the statistical study the computer program statistical SPSs© (version 10.0) for WINDOWS© was used. Photo 1: Radiotracking necklaces and metallic numbered rings. Photo 3: Radiotracking of the released partridges. Photo 2: Acclimatization cages. RESULTS. When analysing dispersion data of the birds regarding to the release point we obtained a mean value of m for the hand reared partridges and for the wild ones. The maximum dispersion data defined as the maximum distance travelled by each one of the individuals from the release point, were of m for the first method and m for the second. Minimum dispersion was of m for the hand reared and for the wild partridges (Graphic 1). When we study the home range or the habitat surface that each animal needs to carry out vital activities and defined by the minimum convex polygon that includes 95% of the localizations of each animal (excluding the release point), we obtained a mean value of 7.81 hectares for the hand reared partridges and for the wild ones, with a maximum home range of hectares for the first group and for the second group (Graphic 2). Released farm chickens never got integration in the wild partridges coveys. In some occasions these chickens were seen in the proximities of a wild covey, but it could never be proven his integration because never were seen with the covey again in later localizations. However, all the wild chickens got integration in wild coveys, normally 1-2 days after release. Graphic 1: Dispersion results.Graphic 2: Home Range results. DICUSSION. Ours results show low dispersions rates registered for the hand reared red-legged partridges studied, in comparison with wild ones. We consider that the main reason for this low dispersion is the incapacity of game farm partridges to join autochthonous wild coveys, so after some days of small erratic movements, they settled down in an area that covered their nutritious necessities, being all their later localizations practically superimposed. So we consider the integration in coveys by wild released chickens like the esential factor for the dispersion and home range registered for this group. These animals presented long dispersions specially first days after release, probably looking for coveys, and subsequent dispersions reflected the wild coveys movements. Home range of these partridges reflected too wild coveys home range in the study area. Therefore, everything seems to take us to the conclusion that the production systems and handling practices of commercial game farms have modified in a remarkable way the ethological patterns characteristic of the species, originating adaptation and integration in the wild problems and impeding them to survive enough time to complete their reproductive cycle once released to the field. BIBLIOGRAPHY. GAUDIOSO, V.R.; ALONSO, M.E.; ROBLES, R.; GARRIDO, J.A.; OLMEDO, J.A. (2002). Effects of housing and breeding system on the reproductive capacity of the Red- Legged Partridge (Alectoris rufa). Poultry Science 81: GORTÁZAR, C.; MARCO, J.; FERNÁNDEZ DE LUCO, D. (1997). Repoblaciones con perdiz roja. Su efectividad en la práctica. Trofeo 326: KENWARD, R.E.; HODDER, K.H. (1996). Ranges V. An analysis system for biological location data. Institute of Terrestrial Ecology. Furzebrook Research Station. Wareham, Dorset. U.K. LUCIO, A. (1992). Gestión de las poblaciones de perdiz roja. En: La Perdiz Roja. Gestión del hábitat. Fundación La Caixa. Ed. Aedos