ABSTRACT Agricultural ecosystems host a large variety of organisms that can contribute to weed control through seed consumption. However, seed consumption rates in the agroecosystems of southern Chile are virtually unknown. We experimentally evaluate oat seed consumption by birds, rodents and invertebrates, in hedgerows dominated by trees, shrubs and grasses. Seed biomass consumed was not affected by the dominant vegetation present in the hedgerows, but did vary according to the seed consuming animal group. The principal seed consumers were rodents, followed by invertebrates and birds, the latter only appearing to be significant in shrub-dominated habitats. In addition, we observed the exotic slug Deroceras reticulatum consuming seeds in 62% of the experimental stations. Additional studies addressing the spatial-temporal dynamics of interactions between granivores and weed seeds are required to confirm the potential controlling and regulating function of rodents on weeds in the agricultural ecosystems of southern Chile.

RESUMEN Los ecosistemas agrícolas albergan gran variedad de organismos que pueden contribuir al control de malezas a través del consumo de semillas. Sin embargo, la tasa de consumo de semillas en agroecosistemas del sur de Chile es desconocido. Evaluamos experimentalmente el consumo de semillas de avena por aves, roedores e invertebrados en cercos vivos dominados por árboles, arbustos y pastos. La biomasa de semillas consumida no fue afectada por la vegetación dominante presente en los cercos vivos, pero varió de acuerdo al grupo de animales consumidores de semillas. Los principales consumidores de semillas fueron los roedores, seguidos por las babosas y por las aves; estas últimas solo parecen ser significativas en habitats dominados por arbustos. Además, observamos la presencia de la babosa exotica Deroceras reticulatum consumiendo semillas en el 62% de las estaciones experimentales. Se requieren estudios adicionales sobre la dinámica espacio-temporal de las interacciones entre los granívoros y las semillas de malezas para confirmar la potencial función controladora y reguladora de los roedores sobre las malezas presentes en los ecosistemas agrícolas del sur de Chile.

Dietary studies contribute to our understanding of bird ecology and are an important source of information for programs promoting the conservation of organisms. We contrasted fecal and stomach content methods of dietary analysis in the Black-faced Ibis and the Southern Lapwing, in order to evaluate the degree of sensitivity in distinguishing consumed prey. Diversity and abundance of prey detected were greater in stomach content samples than in fecal samples in both bird species. The Southern Lapwing did not show association in the number of prey, or a similarity in the taxonomic composition of preys between both methods, suggesting a lack of reliability in the fecal analysis that might lead to misunderstanding the trophic ecology of this bird species. The Black-faced Ibis, show a high association in the number of preys between both methods, and the taxonomic composition and abundance of prey in feces were concordant with that detected in the stomach contents, suggesting that the fecal analysis give reliable results which are coherent between both methods of dietary analysis; this method of analysis is, therefore, recommended, and must be complemented with molecular methods of stomach content analysis, such as the stable isotopes if the scopes of the research is to carry out long term studies.

Los estudios dietarios contribuyen a comprender la ecología de las aves y son relevantes en programas de conservación de los organismos. Contrastamos los métodos de análisis dietarios fecales y estomacales en la Bandurria y en el Queltehue, para evaluar su sensibilidad para discriminar las presas consumidas. La diversidad y la abundancia de presas detectadas fueron mayores en los estómagos que en las heces en ambas especies de aves. El Queltehue no mostró una asociación en el número de categorías tróficas, ni una similitud en la composición taxonómica de la dieta entre ambos métodos, lo que sugiere que los análisis fecales no son confiables y pueden conducir a interpretaciones erróneas de la ecología trófica de esta especie de ave. La Bandurria mostró una alta asociación en el número de presas entre ambos métodos y la composición taxonómica y abundancia de presas en las heces fue concordante con la detectada en los estómagos, sugiriendo que los análisis fecales entregan resultados confiables y coherentes entre ambos métodos de análisis dietario; se recomienda su uso complementado con métodos moleculares de análisis de contenido estomacal como los isótopos estables si el objetivo de la investigación es desarrollar estudios a largo plazo.

We report the capture of a female pampas cat in Quebrada Jerez, Toconao (23º 11´ S y 67º 59´O, 2475 m.s.n.m.), Atacama desert (Norte Grande of Chile). This capture and more records with camera traps confirm the presence of the subspecies Leopardus colocolo colocolo in the Antofagasta Region.We provide biometric and craniometric data on the specimen and confirm by a canine radiography the juvenile status of this felid.

Registramos en Quebrada Jerez, Toconao (23º 11´ S y 67º 59´O, 2475 m.s.n.m.), desierto de Atacama (Norte Grande de Chile), la captura de un gato colocolo hembra. Esta captura más nuevos registros con trampas cámaras confirman para la subespecie Leopardus colocolo colocolo su presencia en la Región de Antofagasta. Presentamos datos biométricos y craneométricos y confirmamos por una radiografía de su dentición el estatus juvenil de este felino.

ABSTRACT In forest ecosystems, numerous species of insectivorous birds use certain tree species as feeding and nesting substrates. Between 2009 and 2010, the use of different floristic components as feeding substrate by the Pygarrhichas albogularis King, 1831 was evaluated in a southern Chilean secondary native forest. From a total of 13 trees and bush species, six tree species were used by P. albogularis as a feeding substrate. Tree use was limited to intermediate heights (11-20 m) and, mainly, to the trunk (40% of observations) and secondary branches (26%). Pygarrhichas albogularis showed a disproportionated use of N. dombeyi and an important use of trees with a greater age structure (DBH 81-100 cm). Nothofagus dombeyi presented a significantly greater tree bark crevice depth than E. cordifolia. In turn, covariance between crevice depth and invertebrate supply in tree bark was positive and significant. We consider bark depth and invertebrate supply to be the proximate causes explaining P. albogularis disproportionated use of Nothofagus dombeyi.

RESUMEN En ecosistemas boscosos, numerosas especies de aves insectívoras usan ciertas especies de árboles como sustrato de alimentación y de nidificación. Evaluamos el uso de Pygarrhichas albogularis King, 1831 por componentes florísticos utilizados como sustrato de alimentación en un bosque nativo en el sur de Chile entre el 2009 y 2010. De 13 especies de árboles y arbustos P. albogularis utilizó seis especies de árboles como sustrato de alimentación. El uso de los árboles se limitó a alturas intermedias (11-20 m) y principalmente utilizó el tronco (40% observaciones) y las ramas secundarias (26%) de los árboles como sustrato de alimentación. Pygarrhichas albogularis mostró un uso desproporcionado por Nothofagus dombeyi y un uso importante por árboles con la mayor estructura etárea (DAP 81-100 cm). Por su parte, N. dombeyi presentó una profundidad de las grietas de la corteza significativamente mayor que E. cordifolia. A su vez, la profundidad de las grietas covarió positiva y significativamente con la oferta de invertebrados en la corteza de los árboles. Consideramos la profundidad de la corteza y la oferta de invertebrados como las causas próximas que podrían explicar el uso desproporcionado de P. albogularis por Nothofagus dombeyi.

BACKGROUND: Frugivorous birds are phenologically linked to the fruits that they eat. When there is less fruit in seasonal environments, frugivorous birds complement their diet by eating invertebrates. The depth of the phenological link between frugivorous birds and their dietary resources has not been studied until now. The objective was to determine the possible phenological synchrony between the Austral thrush (Turdus falcklandii) and its dietary resource, fruits and annelids, found in the fragmented forests in the South of Chile. RESULTS: The numbers of thrushes, annelids, and fruits in fragments of native forest and anthropogenic grassland in Chile's Lake District were estimated annually. Spatial variation (i.e., forest and grassland) and seasonal variation (i.e., the period of greatest fruit growth and least fruit growth) on thrushes, annelids, and fruits were analyzed with a nonparametric Scheirer-Ray-Hare extension for the Kruskal-Wallis test. The graphic representation of the seasonal variation of thrushes, annelids, and fruits was carried out using cubic spline routines. It was found that there are seasonal changes in the dietary resources of these birds. During the period of greatest fruit production, there was a trend towards a higher number of thrushes in the forest where there was a greater availability of ripe fruit in relation to the nearby grasslands. In the grasslands, the annelids demonstrated a trend towards greater quantities in comparison with the forest. There was a positive and significant correlation between the thrushes and the annelids and fruits, indicating phenological synchrony between this bird and its dietary resources. CONCLUSIONS: Therefore, we concluded that the thrush responded numerically and functionally to the variations in its resources. The result of our research underlines the importance of grasslands in maintaining thrush populations, with this bird acting as one of the most important seed dispersers in the temperate southern forests of Chile.

BACKGROUND: The geographical distribution of the Chilean flamingo (Phoenicopterus chilensis) includes the southern-central Neotropics. Despite its wide distribution, currently there is no dietary information on its southern distribution range. From June to September 2011, we quantified the diet and prey availability of the Chilean flamingo in the marine wetland of Caulín (41°48' S, 73°37' W), southern Chile. RESULTS: The prey availability related to both plankton and benthos were four species of copepods, four polychaetes, one foraminifera, and two amphipods. The diet of the Chilean flamingo was composed of foraminifera (Ammonia beccarii), copepods (Harpacticus sp.) and polychaetes. The most abundant prey items from feces of flamingos were Ammonia beccarii and Harpacticus sp. The diameter of A. beccarii consumed by flamingos ranged between 400 and 900 µm, while its width varied between 100 and 300 µm. The width of Harpacticus sp. consumed ranged between 160 and 260 µm. The similarity between flamingo diet and prey availability was 0.553. The diversity of prey organisms in the benthos was higher than that observed from plankton and feces of birds. A. beccarii was preferred over other prey consumed by flamingos. This preference is not related to the size of Harpacticus sp. but to their ability to swim and escape from flamingos. CONCLUSIONS: The dietary similarity of the Chilean flamingo versus the availability of prey in the environment (plankton and benthos) was 55%, indicating that the Chilean flamingo is a partially selective predator.

Numerous vertebrates, and in particular birds, ingest stones (geo-gastrolites) to favour the breakdown and digestion of food in the muscular stomachs. Between 1993 and 1994 we evaluated the quantity, relative abundance and quality of autochthonous (geo-gastrolites) and allochthonous (pieces of glass) components of the grit in gizzards of black-faced ibis (Theristicus melanopis) inhabiting the pastures of southern Chile. Grit elements were present in 32 out of 48 (66,7%) of all gizzard analysed. A total of 572 particles were recorded from which, 69.1% corresponded to autochthonous elements and 27.8% were allochthonous particles. Both components are similar in shape; however glass contributes considerably more in terms of mass. Gender differences reveal that females consume a significantly greater number of allochthonous elements than males. We postulate the hypothesis that, due to their high energy requirements, females ingest more pieces of glass to facilitate the breakdown and digestion of food with a limited nutritional value, thus increasing their reproductive success.

Numerosos vertebrados y en particular las aves, ingieren piedras (gastrolitos) para favorecer la maceración y la digestión del alimento en los estómagos musculares. Entre 1993 y 1994 evaluamos la cantidad, abundancia relativa y calidad de componentes autóctonos (piedras) y alóctonos (trozos de vidrios) de los gastrolitos presentes en las mollejas de bandurrias (Theristicus melanopis) en praderas agrícolas del sur de Chile. Los gastrolitos se presentaron en 32 de las 48 (66,7%) mollejas analizadas. Se registró un total de 572 partículas de las cuales 69,1% fueron elementos autóctonos y 27,8% partículas alóctonas. Ambos componentes no difirieren en la forma pero los vidrios aportaron significativamente mayor masa. Las hembras consumieron un número significativamente mayor de elementos alóctonos que los machos. Postulamos la hipótesis que las hembras, con alto requerimiento energético, ingieren más trozos de vidrio para incrementar la eficiencia de maceración y digestión de alimentos con reducido valor nutricional, lo que les permitiría incrementar su éxito reproductivo.

We evaluated the composition and seasonal variation in the diversity of an aquatic bird assemblage related to a mussel farm in southern Chile. Observations were carried out during spring 2008, and the summer, autumn and winter of 2009. Neotropic cormorant Phalacrocorax brasilianus, followed by kelp gull Larus dominicanus and imperial cormorant P. atriceps were the dominant species. We identified five dietary groups, of which piscivorous birds had the greatest representation. Finally, we discuss the need to evaluate the potential impacts generated by the intensive mussel farming on various components of the marine ecosystem in southern Chile.

The richness and composition of bird species in the Atacama desert located in the Far North of Chile, was studied between 1996 and 1998. Using lineal transects, the richness of bird species was evaluated in nine locations of the Atacama Desert, grouped into four ecological zones: Coastal Desert, Inland Desert, Marginal Tropical, and Altitude Tropical. Bird species richness totaled 80 species, belonging to 51 genera and 26 families. Total richness corresponded to 52% of historical descriptions of birdlife in the Chilean Far North desert. The ecological zones of the coastal and altitude tropical desert areas each have unique bird fauna elements. Insectivorous birds predominated over other trophic groups (40% of total species). The predominance of different trophic groups appears to depend on the type of feeding habitat used. Our results suggest that the variety of bird species in the Chilean Atacama Desert is determined by habitat heterogeneity and the immigration of species from zones, adjacent to the Atacama Desert.

Se evaluó la riqueza y composición de especies de aves en el desierto de Atacama, Norte Grande de Chile, entre 1996 y 1998. Mediante transectos lineales se estimó la riqueza de especies de aves en 9 localidades del desierto de Atacama agrupadas en cuatro zonas ecológicas: Desierto Litoral, Desierto Interior, Tropical Marginal y Tropical de Altura. La riqueza total de aves fue de 80 especies distribuidas en 51 géneros y 26 familias. La riqueza total observada corresponde al 52% de las aves históricamente descritas para el desierto del Norte Grande de Chile. Las zonas ecológicas del desierto litoral y tropical de altura poseen elementos avifaunísticos únicos para cada zona. Las aves insectívoras predominaron entre los demás gremios tróficos (40% del total de especies). La predominancia de los diferentes gremios tróficos parece estar determinada por el tipo de habitat utilizado para alimentarse. Nuestros resultados permitirían sugerir que la riqueza de especies de aves en el desierto de Atacama, Norte Grande de Chile, estaría d eterminada por la heterogeneidad del habitat e inmigración de especies provenientes de zonas adyacentes al desierto de Atacama.