Female-female competition is influenced by forehead patch expression in pied flycatcher females

There is increasing evidence that sexual selection operates in females and not only in males. However, the function of female signals in intrasexual competition has been little studied in species with conventional sex roles. In the Iberian populations of the pied flycatcher (Ficedula hypoleuca), some females express a white forehead patch, a trait that in other European populations, only males exhibit and has become a classical example in studies of sexual selection. Here, we investigated whether the expression of this trait plays a role in female-female competition during early breeding stages. To test this hypothesis, we simulated territorial intrusions by challenging resident females with stuffed female decoys expressing or not a forehead patch. We found that resident females directed more attacks per trial and maintained closer distances to non-patched decoys than to patched ones. Also, patched females were more likely to attack the decoy than non-patched females. Interestingly, females were more aggressive against the decoys when their mate was absent. This may indicate that females relax territory vigilance in the presence of their mate or that males interfere in the interaction between competing females. The behavior of resident males was also observed, although it was not affected by decoy's patch expression. Our findings suggest that the forehead patch plays a role in female intrasexual competition. If the forehead patch signals fighting ability, as it does in males, we may interpret that non-patched females probably avoided repeating costly agonistic encounters with the most dominant rivals.Fil: Morales, J.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; EspañaFil: Gordo, O.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; España. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; EspañaFil: Lobato, E.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; España. Cibio - Centro de Investigação Em Biodiversidade E Recursos Genéticos; PortugalFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Departamento de Zoología. Cátedra de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Martínez de la Puente, J.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; España. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; EspañaFil: Tomás, G.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; EspañaFil: Merino, S.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; EspañaFil: Moreno, J.. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; Españ

The Subantarctic Rayadito (Aphrastura subantarctica), a new bird species on the southernmost islands of the Americas

We describe a new taxon of terrestrial bird of the genus Aphrastura (rayaditos) inhabiting the Diego Ramírez Archipelago, the southernmost point of the American continent. This archipelago is geographically isolated and lacks terrestrial mammalian predators as well as woody plants, providing a contrasted habitat to the forests inhabited by the other two Aphrastura spp. Individuals of Diego Ramírez differ morphologically from Aphrastura spinicauda, the taxonomic group they were originally attributed to, by their larger beaks, longer tarsi, shorter tails, and larger body mass. These birds move at shorter distances from ground level, and instead of nesting in cavities in trees, they breed in cavities in the ground, reflecting different life-histories. Both taxa are genetically differentiated based on mitochondrial and autosomal markers, with no evidence of current gene flow. Although further research is required to define how far divergence has proceeded along the speciation continuum, we propose A. subantarctica as a new taxonomic unit, given its unique morphological, genetic, and behavioral attributes in a non-forested habitat. The discovery of this endemic passerine highlights the need to monitor and conserve this still-pristine archipelago devoid of exotic species, which is now protected by the recently created Diego Ramírez Islands-Drake Passage Marine Park.Fil: Rozzi, Ricardo. Universidad de Magallanes; Chile. University of North Texas; Estados UnidosFil: Quilodrán, Claudio S.. Universidad de Magallanes; Chile. Universite de Fribourg;Fil: Botero Delgadillo, Esteban. Max Plank Institute for Ornithology; Alemania. Universidad de Chile; ChileFil: Napolitano, Constanza. Universidad de Magallanes; Chile. Universidad de Los Lagos; Chile. Instituto de Ecología y Biodiversidad; ChileFil: Torres Mura, Juan C.. Universidad de Magallanes; Chile. Union de Ornitologos de Chile; ChileFil: Barroso, Omar. Universidad de Magallanes; ChileFil: Crego, Ramiro D.. Conservation Ecology Center; Estados UnidosFil: Bravo, Camila. Universidad de Chile; ChileFil: Ippi, Silvina Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Quirici, Verónica. Universidad Andrés Bello; ChileFil: Mackenzie, Roy. Universidad de Magallanes; ChileFil: Suazo, Cristián G.. Universidad de Magallanes; Chile. Justus Liebig Universitat Giessen; AlemaniaFil: Rivero de Aguilar, Juan. Universidad de Magallanes; ChileFil: Goffinet, Bernard. Universidad de Magallanes; Chile. University of Connecticut; Estados UnidosFil: Kempenaers, Bart. Max Plank Institute for Ornithology; SuizaFil: Poulin, Elie. Universidad de Magallanes; Chile. Universidad de Chile; ChileFil: Vásquez, Rodrigo A.. Universidad de Magallanes; Chile. Universidad de Chile; Chil

Latitude does not influence cavity entrance orientation of South American avian excavators

In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e., farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e., colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15°S ? 55°S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model selection procedure was used to simultaneously examine multiple orientation hypotheses in each ecoregion, to explore underlying cavity-orientation patterns. Contrary to predictions, and patterns from the Northern Hemisphere, birds did not orient their cavities more toward the equator with increasing latitude, suggesting that latitude may not be an important underlying selective force shaping excavation behavior in South America. Moreover, unimodal cavity-entrance orientations were not frequent among the ecoregions analyzed (infour ecoregions), whereas bimodal (in five ecoregions) or uniform (in three ecoregions) werealso common, although many of these patterns were not very sharp. Our results highlight the need to include data from under-studied biotas and regions to improve inferences at macroecology scales. Furthermore, we suggest a re-analysis of Northern Hemisphere cavity orientation patterns using a multimodel approach, and a more comprehensive assessment of the role of environmental factors as drivers of cavity orientation at different spatial scales in both hemispheres.Fil: Ojeda, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Schaaf, Alejandro Alberto. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Altamirano, Tatiana Edith. University of British Columbia; CanadáFil: Bonaparte, Eugenia Bianca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Bragagnolo, Laura Araceli. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Chazarreta, L.. Secretaría de Ambiente y Desarrallo Sustentable de la Nación; ArgentinaFil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Dias, R.. Universidade do Brasília; BrasilFil: Di Sallo, Facundo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Ibarra, T.. Pontificia Universidad Católica de Chile; ChileFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jauregui, Adrian. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Área Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jimenez, Jaime E.. Universidad de Magallanes; ChileFil: Lammertink, J. Martjan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Lopez, F.. Universidad Nacional de La Pampa; ArgentinaFil: Nuñez Montellano, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: de la Peña, Martín. No especifíca;Fil: Rivera, Luis Osvaldo. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Vivanco, Constanza Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Santillán, Miguel. Museo de Historia Natural de La Pampa; ArgentinaFil: Soto, G.. Cornell University; Estados UnidosFil: Vergara, P.. Universidad de Santiago de Chile; ChileFil: Politi, Natalia. University of North Texas; Estados Unido

Anti-predator responses in the Chilean Swallow Tachycineta leucopyga breeding in northwest Patagonia

Capsule: Breeding Chilean Swallows Tachycineta leucopyga in Argentina use visual and acoustic signals in response to potential threats from a predator, but these did not vary with brood age. Aims: To study anti-predator behavioural responses in breeding Chilean Swallows from North Patagonia, Argentina, by using a nest-box experiment. Methods: At days eight and 14 after the first nestlings hatched, Chilean Swallow breeding adults were exposed to a stuffed decoys of either a natural local predator, the Austral Pygmy-Owl Glaucidium nana, or a neutral decoy, a stuffed Rufous-Collared Sparrow Zonotrichia capensis. Results: Anti-predator behavioural responses consisted of displaying dives, circling flights and group mobbing around the predator decoy, together with the emission of several vocalizations, among which a mobbing alarm call was the most frequent. We did not find significant differences in the intensity of parental nest defence behaviours at different nestling ages (8 and 14 days old). Conclusion: Anti-predator behaviour of breeding Chilean Swallows consists of visual and acoustic signals, involving swallows other than the nest owners, and without variation during the nestling period. Our exploratory assessment on the anti-predator behaviour of Chilean Swallows is the first description of the southernmost Neotropical swallow defence behaviour and will therefore help delineate future research.Fil: Barrionuevo, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ojeda, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Dudinszky, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Departamento de Zoología. Cátedra de Vertebrados; Argentin

Distribution extension of a rare Phymaturus lizard (Squamata: Liolaemidae) reaching Nahuel Huapi National Park (Argentina)

The Phymaturus lizards from arid South America are Vulnerable because of restricted distributions of most species (not overlapping protected areas), life history attributes (e.g., viviparity), and taxonomic redefinitions that obstruct conservation assessments. Among the new species is P. tenebrosus, endemic to a small area in northwestern Argentine Patagonia where a century of sheep farming intensified the natural fragmentation of its habitat: rocky outcrops. We recorded P. tenebrosus in the ecotone between Andean forests and arid steppe, west of previous documented sites. Our sightings were on both sides of the Limay River, hence, within the Nahuel Huapi National Park. Although the Park is under conservation measures, the area where P. tenebrosus was found is heavily impacted by livestock. Therefore, we encourage studies on these reptiles east and west of the Limay River (for population divergences are expectable due to such a natural barrier), and long-term monitoring within the national park.Fil: Kubisch, Erika Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ippi, Silvina Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Karlanian, Juan. Administración de Parques Nacionales. Delegación Regional Patagonia; ArgentinaFil: Ojeda, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Shared territorial defence in the suboscine Aphrastura spinicauda

Territorial behaviour is an active and typically aggressive behaviour used to defend resources. Here, we investigated the presence of shared territorial defence behaviour during conspecific intrusions in the Thorn-tailed Rayadito (Aphrastura spinicauda), a suboscine species that generally does not maintain long-term pair bonds. We found that, compared to females, males displayed more alarm calling during their response, approached closer and were also more physically aggressive towards conspecific intruders. Despite these differences, the defence behaviour ofmales and females was highly correlated during territorial responses to simulated intruders. To our knowledge, this is the first report of coordinated or joint territorial defence in a South American suboscine that generally only maintains short-term pair bonds.Fil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Instituto de Ecología y Biodiversidad; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Dongen, Walter van. Victoria University; Australia. Instituto de Ecología y Biodiversidad; ChileFil: Lazzoni, I.. Universidad de Chile; ChileFil: Vasquez, Rodrigo A.. Universidad de Chile; Chil

Tree size and crown structure explain the presence of cavities required by wildlife in cool-temperate forests of South America

Maintenance of tree cavity supply is a global conservation priority for forest wildlife, which requires understanding the ecology and population dynamics of cavity-bearing trees. Explaining the occurrence of cavities in trees is particularly important in ecosystems where most secondary cavity-users (SCUs) are critically dependent on the slow formation of cavities by wood-decay processes. Our main objectives were (1) to explain the distribution of decay cavities in trees according to their individual attributes and, (2) to quantify the relative importance of each individual tree attribute to determine the presence of decay cavities. We focused on medium and large decay cavities (smallest entrance dimension ≥ 5 cm), which can limit populations of management-sensitive SCUs. We measured forest attributes and inspected cavities in trees (n = 860) and snags (n = 93) in six 0.5 ha plots from old- and second-growth Nothofagus dombeyi forest stands. We used generalised linear mixed-effects models (GLMM) to analyse the distribution of decay cavities in trees using data on their presence/absence, based on several tree individual attributes, across different sites. We applied an information-theoretical and multi-model inference approach to quantify the strength of alternative sets of hypotheses/models. We used model averaging, which allows estimating coefficients and making inferences that account for model and parameter uncertainty. Diameter at breast height (DBH), crown damage and decay, crown ratio (crown length • trunk length−1) and woodpecker foraging signs were important to explain the presence/absence of decay cavities in trees. Diameter at breast height, woodpecker foraging signs and a moderate-high crown damage and decay were positively related with decay cavity presence. The presence of medium and large decay cavities was also positively related with DBH, but trees with low crown ratios had relatively low probabilities of presenting these cavities, even with DBHs > 150 cm. Trees with DBHs smaller than 50 cm had very low probabilities (<0.25–0.30) to present decay cavities, while the probability of trees presenting decay cavities of medium and large sizes was very low for trees with diameters < 100 cm, even for trees with high crown ratios. Our results point out that conservation of large diameter trees with high crown ratios is important to maintain the supply of decay cavities required by management-sensitive SCUs in these forests. As these keystone structures are globally threatened by climate change induced disturbances (e.g. fires, droughts), they should be maintained/restored through forest management (e.g. retention of keystone structures) to achieve cavity-using wildlife habitat conservation in the long-term.Fil: Dudinszky, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Kitzberger, Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Cerón, Geardo Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ojeda, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Mobbing behaviour in non-breeding flocks of a passerine bird in northern Patagonia

Animal cooperation occurs in both genetically related and unrelated groups of individuals, involving costs and benefits that have not been fully elucidated. For example, risky behaviour such as mobbing a predator would be selected if participants are genetic relatives because they share a fraction of their gene pool (i.e., kin selection or indirect benefits). However, in the absence of genetic relatedness, benefits can be achieved by direct benefits such as reciprocity or mutualism, among others. In this study we analyzed the cooperative mobbing behaviour in winter flocks of an endemic passerine of the austral temperate forests, the Thorn-tailed rayadito (Aphrastura spinicauda). We first tested whether the probability of and the latency to mobbing response differed depending on the acoustic stimulus perceived by the flock (i.e., conspecific mobbing calls vs. predator calls), and whether the intensity of the mobbing was related to the number of individuals and species participating. We found that flocks were more likely to approach the predator when the acoustic signal was a conspecific mobbing call than when it was the predator's call, and that the intensity of mobbing increased with the number of participants. Secondly, we explored if the level of kinship within the group potentially played a role in the development of the mobbing behaviour. The proportion of close-relatives found in these flocks was low, and the within- and among-flock degree of kinship did not differ. This suggests that kin selection might not be related with the expression of mobbing behaviour in winter flocks.Fil: Ippi, Silvina Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Bravo, Camila. Universidad de Chile; ChileFil: Botero Delgadillo, Esteban. Universidad de Chile; ChileFil: Poulin, Elie. Universidad de Chile; ChileFil: Vásquez, Rodrigo A.. Universidad de Chile; Chil

Relationships among territory size, body size, and food availability in a specialist river duck

Models of territorial behaviour predict a reduction in territory size when food availability and competitive pressure increase. Moreover, body size can play an important role in territorial defence. The Torrent Duck (Merganetta armata) is a river specialist that exhibits year-round territorial behaviour and long-term pair bonds. Food availability measured as biomass of invertebrates per unit area, territory and body size of Torrent Ducks were studied in the Andes in Argentina to test predictions of territoriality models. The availability of aquatic invertebrates decreased with latitude, while territory size increased. As expected, territory size of Torrent Ducks showed a negative relationship with the availability of aquatic invertebrates, a major food source for Torrent Ducks. Larger males and females paired together and occupied territories with greater food availability. Body size may be important for both males and females for the successful acquisition and defence of territories, especially during the non-breeding season when the contest winner acquires or maintains the territory and the mate. Our results suggest that Torrent Duck specialisation on fast-flowing mountain rivers leads to year-round territoriality in both sexes, a positive correlation between territorial defence and body size, and territory size proportional to food availability and population density.Fil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Cerón, Gerardo. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; ArgentinaFil: Alvarez Guerrero, Leandro Manuel. Asociación para la Conservación y el Estudio de la Naturaleza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Aráoz, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; ArgentinaFil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Artrópodos en la dieta del ensamble de aves que habitan el paisaje rural del norte de la Isla de Chiloé, Chile

La información sobre los distintos componentes de la dieta de aves resulta relevante para entender las variaciones poblacionales y la subsistencia de comunidades ante la modificación del paisaje. Sin embargo, a la fecha, falta infor‐ mación cuantitativa sobre la composición de la dieta a nivel comunitario en el Neotrópico. A pesar de que el consumo de frutas y semillas por aves ha sido bien documentado para los ecosistemas templados del sur, el consumo de artrópodos ha recibido menos atención a pesar de su relevancia en la dieta de las aves. En este trabajo describimos y evaluamos la diversidad de artrópodos en la dieta de miembros de distintos gremios tróficos de la comunidad de aves de los bosques templados del sur de Sudamérica en el norte de la Isla de Chiloé, Chile (42°S). Para cada especie de ave capturada, estimamos la composición y la diversidad trófica de artrópodos en la dieta en base al análisis de heces. Registramos el consumo de artrópodos en 17 de las 18 especies capturadas, sugiriendo que el consumo de artrópodos está ampliamente distribuido en la comunidad de aves analizada. La Golondrina chilena (Tachycineta leu‐ copyga), especie insectívora, tuvo el mayor número de artrópodos promedio por muestra y, a la vez, la menor diversi‐ dad de órdenes de artrópodos en su dieta. Por el contrario, el Chercán (Troglodytes aedon), especie insectívora, registró la mayor diversidad de artrópodos consumidos. Entre las especies omnívoras, tanto el Tordo (Curaeus curaeus) como el Fio‐fio (Elaenia albiceps), consumieron principalmente coleópteros. Finalmente, los órdenes de artrópodos registrados variaron entre aves pertenecientes al mismo gremio así como también entre distintos gremios tróficos.Knowledge of bird diets is important to understand population fluctuations and the persistence of bird communities in changing landscapes. However, there is a general lack of quantitative information about the composition of bird diets at the community level in the Neotropics. Although consumption of fruits and seeds by birds has beenwell documented for forest ecosystems in southern South America, consumption of arthropods has received less attention, despite their relevance in bird diets. Here we describe and evaluate the presence and diversity of arthropods consumed by members of different dietary guilds of the avian community from temperate forests and rural landscapes in northern Chiloé Island, Chile (42°S). We estimated the proportion of arthropods consumed by all bird species captured using mist nests in a mixed rural landscape, and identified arthropods at the order level, based on remainscontained in bird droppings. In addition, we estimated trophic diversity for those bird species with the highest number of samples. Arthropod remains were prevalent in dropping contents for nearly all sampled species (17 out of 18 captured species), indicating that arthropod consumption is broadly distributed in the avian assemblage. The insectivorous Chilean swallow (Tachycineta leucopyga) had the highest average number of arthropods per sample but the lowest arthropod diversity. On the contrary, the highest arthropod diversity in droppings corresponded to the insectivorousHouse Wren (Troglodytes aedon). The omnivorous species, Austral Blackbird (Curaeus curaeus) and Whitecrested Elaenia (Elaenia albiceps) consumed mainly Coleoptera. Finally, arthropod orders found in droppings varied among bird species from the same and between dietary guilds.Fil: Muñoz, César E.. Instituto de Ecología y Biodiversidad; Chile. Pontificia Universidad Católica de Chile; ChileFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Instituto de Ecología y Biodiversidad; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Celis Diez, Juan L.. Pontificia Universidad Católica de Valparaíso; ChileFil: Salinas, Daniel. Instituto de Ecología y Biodiversidad; ChileFil: Armesto, Juan J.. Instituto de Ecología y Biodiversidad; Chile. Pontificia Universidad Católica de Chile; Chil