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Weak short-term survival of radio-tagged Pin-tailed Sangrouse (Pterocles alchata) in France raises questions about capture and attached transmitters. Radio-telemetry is widely used by conservation biologists for collecting data on habitat use by animal species, a central topic in population ecology. For this purpose, the capture of individuals and attachment of transmitters on animals are necessary. Those actions might have a harmful effect on birds but when species are difficult to detect it remains the only method available. We report results of a radio-telemetry study on Pin-tailed Sandgrouse (Pterocles alchata) in France. Although the capture and attachment of transmitters are possible, short-term mortality is very high. Collected data do not explain such a rate. We compare those results to a recent study on the same species in Spain and to a meta-analysis on birds., Un des outils à la disposition des biologistes de la conservation pour étudier comment les espèces utilisent les habitats, thème central en écologie des populations, est la radio-télémétrie. Cette technique impose la capture et la pose d’émetteurs radio. Ces actions peuvent avoir un effet préjudiciable sur les oiseaux mais dans le cadre d’espèces difficiles à détecter, la méthode reste la seule pour acquérir des informations précises. Nous examinons ici le bilan d’un test de suivi radio-télémétrique sur le Ganga cata (Pterocles alchata) en France. Il en ressort que le taux de mortalité à court terme est très élevé. Aucune des informations collectées ne permet de l’expliquer clairement. Ces résultats sont comparés et discutés avec ceux obtenus en Espagne sur cette espèce., Tatin Laurent,Wolff Axel,Paulus Guillaume,Vincent-Martin Nicolas. Suivi radio-télémétrique du Ganga cata (Pterocles alchata) en France. La faible survie observée questionne les effets de la capture et des émetteurs. In: Revue d'Écologie (La Terre et La Vie), tome 71, n°3, 2016. pp. 298-304.

International audience; Survival typically contributes most to population trends in long-lived birds and itsaccurate estimation is therefore vital for population management and conservation. Weevaluated the effects of age, territoriality and reproduction on survival in Bonelli’s EagleAquila fasciata through multistate capture-mark-recapture analyses on a long-termdataset. Monitoring was carried out in southeast France (1990–2008) and involved thesurveying of territorial Eagles, the marking of fledged chicks, and the recording of resightingsand recoveries of marked non-territorial and territorial birds. Survival improvedwith age, but territoriality was not retained in the best model; yearly survival was estimatedat 0.479 for fledglings (to 1 year of age), 0.570 for 1- and 2-year-olds, and 0.870for 3-year-old and older individuals. The second best model supported a furtherincrease in survival from 3-year-olds (0.821) to older individuals (0.880). In the thirdbest supported model, territoriality enhanced survival, but only in 2-year-olds (0.632vs. 0.562 for non-territorial). We found no correlation between the previous breedingstage and future survival, consistent with the long lifespan of the study species. Nevertheless,4-year-old and older successful breeders were more likely to breed the followingyear than failed adult breeders (0.869 vs. 0.582), suggesting that the cost of reproductionis small in comparison with the variation in quality among individuals or theirterritories.

12 páginas, 6 figuras, 3 tablas. [EN]Recruitment is an essential component of the life history and population dynamics of bird species. We provide comprehensive information on the determinants of territorial recruitment in populations of the endangered Bonelli’s Eagle (Aquila fasciata). Field work was based on a long-term study of two populations located in the northwest of this species’ range, one in Catalonia (northeastern Spain) and the other in Provence and Languedoc-Roussillon (southeastern France). Nestlings were banded (n = 451 marked birds) and known territories were intensively monitored during the period 1980–2007. First, a global return rate of 9.97% (45 recruits)was calculated, with no significant differences between the two populations. Second, results showed that both the birth year and the breeding success of the birth territory had significant effects on recruitment probability: nestlings from territories with better breeding success were more likely to recruit. Third, seniority analyses based on capture–resighting techniques were used to estimate the agespecific probabilities that a territorial bird in a given year was inexperienced. The parameter estimates for this probability ranged from 0.985 to 0.999 for 2-year-olds and from 0.763 to 0.808 for 3-year-olds and then fell drastically to 0.066–0.272 for 4-year-olds and older. Fourth, females were found to disperse farther than males. Additionally, there was a significant interaction between sex and area of birth, in that females from Catalonia dispersed farther than females from France. Finally, previously occupied territories located in the highest-quality areas with the highest territorial density were found to be the most attractive to inexperienced individuals. [ES]El reclutamiento es un componente esencial de la historia de vida y de la dinámica poblacional en las aves. En el presente estudio se proporciona información detallada sobre los factores que determinan el reclutamiento territorial en una especie amenazada: Aquila fasciata. Se estudiaron dos poblaciones localizadas en el extremo noroccidental de la distribución de la especie, una en Cataluña (NE de España) y la otra en Provence y Languedoc-Roussillon (SE de Francia). La metodología de campo se basó en un estudio a largo plazo que incluyó marcaje de volantones (n = 451 pollos) y seguimiento de territorios en ambas poblaciones durante el período comprendido entre 1980 y 2007. En primer lugar, se estimó una tasa de retorno global del 9.97 % (45 reclutas), que no difirió significativamente entre las poblaciones estudiadas. En segundo lugar, se detectaron efectos significativos del año de nacimiento y del éxito reproductor del territorio de origen sobre la probabilidad de que un volantón fuera posteriormente reclutado: aquellos pollos de territorios con mayor éxito mostraron mayor probabilidad de reclutamiento. En tercer lugar, se utilizaron técnicas de captura-reavistamiento para estimar la probabilidad de que un individuo territorial de una determinada edad fuera un recluta. Este parámetro mostró valores entre 0.985 y 0.999 para individuos de dos años, entre 0.763 y 0.808 para individuos de tres años, y se redujo drásticamente para individuos de cuatro años o mayores, mostrando valores de ente 0.066 y 0.272. En cuarto lugar, las hembras se dispersaron a mayor distancia que los machos. Además, las hembras de Cataluña se dispersaron a mayor distancia que las hembras de Francia. En último lugar, aquellos territorios previamente ocupados, situados en áreas con elevada densidad y situados en áreas de mayor calidad se mostraron más atractivos para individuos sin experiencia territorial previa. Este estudio fue apoyado por el Ministerio de España de Educación y Ciencia a través del proyecto CGL2007-64805/BOS y la concesión SAB-2006-0014 a Roger Pradel, por la Fundación Miquel Torres (Bodegas Miquel Torres), y la Oficina Tècnica de Planificació i Anàlisi Territorial (Diputación de Barcelona).