New at-sea records of pelagic seabirds in the South Atlantic Ocean and Antarctica

During ship-based seabird surveys in the south Atlantic and Antarctica in the austral summers of 1994/95, 2009, 2010, 2011 and 2012, we documented at-sea distributions of Buller's albatross (Thalassarche bulleri), Atlantic petrel (Pterodroma incerta), soft-plumaged petrel (Pterodroma mollis), Kerguelen petrel (Lugensa brevirostris) and great-winged petrel (Pterodroma macroptera). In some cases, sightings were considered as extralimital, but for other species updating their distributions in the literature seems warranted. Atlantic petrel, for example, has been regularly observed in the Drake Passage and north of the Antarctic Peninsula for about 30 years, but the distribution of this species has not been updated in the literature. The observations reported here will contribute to update the at-sea distributions of these species and to changes in their distributions

Assessing the conservation value of nature reserves: terrestrial birds in Isla de los Estados (Staten Island) Provincial Reserve, Tierra del Fuego, Argentina

Abstract Existing networks of nature reserves contain a biased sample of biodiversity. In Patagonia Argentina, most nature reserves focus their protection objectives on a particular ecosystem, geoform or scenic value, and usually are located in inaccessible areas. However, unique species or assemblages could inhabit less protected ecosystems, areas or habitats, which could be threatened depending of management. In this study, we assessed the conservation value of different ecosystem types and areas (fjords) in Isla de los Estados Provincial Reserve (RPIE, Argentina), using birds as study case. We chose three fjords (east, central and west) and five ecosystems types (forests at low and high elevation, open-lands at low and high elevation, and sea coasts). Bird's assemblage richness, density, biomass, trophic level, migratory status, and use of strata per ecosystems and fjords were characterized in 75 points (3 fjords × 5 ecosystems × 5 replicates) and evaluated using ANOVA and multivariate methods. Also, Shannon (H') and Pielou (J) indices were estimated for fjords and ecosystems. Passerine was the most abundant group, being mainly residents, omnivorous and carnivorous-scavenger, and they were observed mainly flying or in the canopy. Assemblage structure and function varied with ecosystem types, with higher richness and biomass in coasts and open-lands than in other ecosystems, but with greater density in forests. Multivariate analyses showed conspicuous groups for forests and coast sampling units, with significant differences among all ecosystem types except between low and high forests. Also, east fjord significantly differed in density and biomass from the others, but west fjord also differed in structure, function and bird assemblage. We conclude that greater conservation value must be assigned to ecosystem types or areas inhabited by threatened species (as open-lands at high elevation) and highest richness and variety of use of strata (as sea coasts). However, bird assemblage patterns have particularities in less valuable ecosystems and areas, which also justify their importance for conservation, or at least, prescriptions of low impact uses and activities in the management planning. Nature reserves are opportunities to preserve endemic species, habitats or areas of special interest, as low latitude or unique isolated landscape communities, and ecosystems underrepresented in the network of local, regional or world protected areas

Influence of life history traits on trophic niche overlap between two similar sympatric Tupinambis lizards

Segregation of habitat resources is an important mechanism that allows the coexistence of species. The diet is an important and dynamic component that can generate interactions among co-existing species. Differences in food resource use between related sympatric species have been associated frequently with divergence in multiple phenotypic traits; hence, it is interesting to explore how phenotypic differences allow sympatric species to minimize niche overlap. We aimed to evaluate trophic niche segregation between Tupinambis merianae and T. rufescensin relation to life history traits in a sympatric zone. We compared the volume of the stomach food items between species considering sexual dimorphism, body size classes, sexual maturity and reproductive activity. The obtained Morisita?s index indicated trophic niche overlap between T. merianaeand T. rufescens; however, considering particular food items, we observed differences in diet composition. Moreover, our results indicate that body size, sexual maturity and reproductive activity are relevant factors influencing the diet of these species. Life history traits of these two species of Tupinambisare important because they shape diet composition, contributing to interspecific segregation of the trophic niche and, therefore, allowing species coexistence.La segregación de los recursos del hábitat es un importante mecanismo que permite la coexistencia de especies. La dieta es un componente importante y dinámico, que puede generar interacciones entre especies co-existentes. Las diferencias en la dieta entre especies relacionadas en simpatría han sido frecuentemente asociadas a la divergencia en múltiples caracteres fenotípicos, por lo tanto es interesante explorar cómo las diferencias fenotípicas permiten que las especies simpátricas minimicen la superposición del nicho. Nuestro objetivo fue evaluar la segregación del nicho trófico entre Tupinambis merianae y T. rufescens en una zona de simpatría y entender de qué manera los caracteres de historia de vida podrían influenciar la ecología trófica de estos lagartos. Analizamos el contenido estomacal comparando el volumen de presas consumidas entre especies, considerando además el dimorfismo sexual, las clases de tamaño corporal, la madurez sexual y la actividad reproductiva. El índice de Morisita obtenido indica superposición del nicho trófico entre T. merianae y T. rufescens, pero considerando algunas presas en particular, observamos que las especies muestran diferencias en la composición de la dieta. Por otro lado, nuestros resultados indican que el tamaño corporal, la madurez sexual y la actividad reproductiva son factores relevantes que influyen en la dieta de las especies. Los caracteres de historia de vida de estas dos especies de Tupinambis son importantes porque determinan la composición de la dieta, contribuyendo a la segregación interespecifica del nicho trófico y en consecuencia a la coexistencia de las especies.Fil: López Juri, Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Naretto, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Mateos, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Chiaraviglio, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Cardozo, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Food Habits of the Harpy Eagle, a Top Predator from the Amazonian Rainforest Canopy

The Harpy Eagle (Harpia harpyja), the heaviest and the most powerful bird of prey in the canopy of the Neotropical rainforests, is critically endangered in some parts of its range, mainly due to hunting pressure and habitat loss by deforestation. In this study, we found that the diet of five breeding pairs of Harpy Eagles in the central Amazonian rainforest over three years was dominated by two species of sloths (Bradypus variegatus and Choloepus didactylus) in terms of number of individuals and biomass consumed. Twelve other species, including primates, rodents, carnivores, and birds, also contributed to the Harpy Eagle diet in central Amazonia; there was no evidence of Harpy Eagle predation on livestock or domestic animals. Throughout the Harpy Eagle's entire range, 69 prey species have been documented, indicating that it can use a wide range of food resources. However, in our study, there was an evident diet specialization, resulting in a niche breadth which was relatively low (Bsta = 0.171). Conservation of Harpy Eagles should include protection of nesting trees, territories, and prey species to maintain the variability and availability of resources and its ecological functions throughout its geographic range. © The Raptor Research Foundation, Inc