1. IBERIAN GREY PARTRIDGE (Perdix perdix hispaniensis) HABITAT SELECTION ON THE CANTABRIAN MOUNTAINS. PÉREZ, J.A.; MARTÍNEZ, J.J.; DÍEZ, C.; PRIETO, R.; ALONSO, M.E.; GAUDIOSO, V. Dpto. Producción Animal II, Facultad de Veterinaria de León. 24071. España. E.mail: dp2jpg@unileon.es IV INTERNATIONAL SYMPOSIUM ON WILD FAUNA (TATRANSKA LOMNICA, ESLOVAQUIA)dp2jpg@unileon.es INTRODUCTION. Iberian grey partridge live in mountainous habitats from 1.300 to 2.500m above sea level. Actually the decline of the grey partridge populations is due primarily to agricultural the abandonment of agricultural and stockbreeding practices which allows the encroachment of dense shrublands. OBJETIVES. In an area of the Cantabrian Mountains with an stable population, “Mampodre Hunting National Reserve”, we studied the prefered habitat for the species to know what habitat management practices could be most recomended to increase partridge populations. MATERIAL AND METHODS. The study was based on 3 radio-tagged wild grey partridges (males) captured in the area from three different coveys, and location of sleeping places from five coveys. Animals radio-tagged were equipped with Biotrack  radio transmitter necklaces, with a weight of 9.8 grams and minimum autonomy of 11 months (Photo 1). Once released it was carried out individual birds localizations, two days per week, twice a day, morning and afternoon, through localization trips and using the radio-tracking system, a receiving Yaesu  with directional antenna (PÉREZ et al., 2004). Localization of sleeping places was made beating the area with three fixed routes on foot (1 km long each one) repited twice during march, june, september and december. We counted the number of sleeping places and estimated the number of partridges from each covey. To simplify the study of habitat selection we considered five useful environments for partridges: grazing land (1), young shrubland (2), old shrubland (3), artificially cleared land (4) and reforestation (5) (Photos 1-5). RESULTS. We obtained a positive selection for habitats 1 and 3 from diurnal activity of radio-tagged animals (Graphic 1), with the 77.47% of locations (39.44% and 38.03% respectively) (Graphic 2). Less selected habitat was 2 with only 4.23% of locations. We found some differences between the three animals (Graphics 3, 4, 5). BIBLIOGRAPHY PÉREZ, J.A. (1999). Utilización del radioseguimiento para la valoración del comportamiento de los animales empleados en repoblaciones de perdiz roja (Alectoris rufa). Tesina. Univ. de León. 131 pp. COLL, M. (1991). Repoblaciones de perdiz roja. Los cambios en el ecosistema para la reintroducción de la especie salvaje. En: La perdiz roja. Fundación La Caixa. Ed. Aedos 61-65. CAPELO, M.; CASTRO PEREIRA, D. (1996). Sobrevivencia e dispersao de perdizes (Alectoris rufa L.) largadas em duas operacoes de repovoamento cinegético. Revista Florestal 9 (1): 243-253. Graphic 1: Habitat selection for the radio- tagged partridges. DISCUSSION. Diurnal activity ofr grey partridges carried out principally in habitats with clear ground where they can find food easily (insects, fresh shoots and grass...) and where they can watch to avoid predators. To choose sleeping places they prefers clear grounds with vegetation coverage. In the last years, mountainous habitat of iberian grey partridge has been degradated because of the decrease of the human activities like extensive stockbreeding or take in firewood, which produce quickly growth of young shrubland, negative for the survival of grey partridges. Therefore, any attempt to increase the populations of iberian grey partridge must involve an important habitat management, as has been studied to with other species like red-legged partridge (COLL, 1998; CAPELO, 1996) Photo 1: Grazing land. Photo 2: Young shrubland. Photo 5: Reforestation.Photo 4: Artificially cleared land. Photo 3: Old shrubland. Graphic 2: Habitat selection for male 1 Graphic 3: Habitat selection for male 2 Graphic 4: Habitat selection for male 3 Sleeping places of coveys were located principally in habitats 3, 5 and 4 with the 88.99% of locations (37.80%, 30.42% and 20.77% respectively) (Graphic 5). Again less selected habitat was 2 with only 2.38% of locations. We found some variations in preferences along the year (Graphic 6). Graphic 5: Total localization of sleeping places.Graphic 6: Localization of sleeping places along the year