1,720,977 research outputs found
Nesting biology of the Small-billed Elaenia (Elaenia parvirostris) in a forest with high conservation value in east-central Argentina
No full textHabitat loss and fragmentation significantly affect avian breeding success. East-central Argentina’s few native forests have become increasingly degraded by humans over time. Understanding the relationship between forest health and nesting success is critical since this information will be valuable as a point of comparison with future research if management actions are not taken. The study had two objectives: 1) describe the nesting biology of the Small-billed Elaenia (Elaenia parvirostris) and 2) assess whether a set of habitat features and time-specific variables had an effect on nest survival. We monitored 99 nests during three breeding seasons (2015–2018). Of all nests, 39% were successful, with predation causing the majority of nest failures (59%). We did not find important effects of habitat features on daily nest survival rate (DNSR). There was a cubic effect of nest age on the DNSR. Estimates of the cumulative probability to survive the entire nesting cycle was 41.2% (55.5% for egg laying, 16.1% for incubation, and 52% for nestling period). Our results add to the scientific understanding of life history strategies for south temperate birds while highlighting the need for additional research on native forest disturbances.Fil: Gonzalez, Exequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Jauregui, Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Segura, Luciano Noel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin
Leptodactylus bufonius (Boulenger, 1894) (Anura, Leptodactylidae). Ampliación del rango de distribución para la provincia de San Juan (República Argentina)
Full text linkAmpliación de la distribución de Leptodactylus bufonius.Fil: Sanabria, Eduardo Alfredo. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vergara Alvarez, Silvia Cristina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wetten, Paula. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aragon y Traverso, Juan Héctor. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Gonzalez, Exequiel. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Inusual apropiación de nido y pichones por parte de la Paloma Torcaza (Zenaida auriculata)
Full text linkReportamos un caso de apropiación interespecífica de nido en donde una Torcaza (Zenaida auriculata) usurpa el nido de un Zorzal Chalchalero (Turdus amaurochalinus). Ambos pichones, incluido un pichón parásito de cría, resultaron muertos tras la usurpación, a pesar de los enérgicos esfuerzos de los zorzales por recuperar el nido y de los repetidos intentos de la paloma para alimentar los pichones. Creemos que la Torcaza perdió sus propios pichones cerca del nido de zorzal y esto motivó la usurpación. Atribuimos el falso reconocimiento de los pichones a un subproducto hormonal causado por la pérdida de sus propios pichones, similar a lo observado en el Pingüino Emperador (Aptenodytes fosteri).We report a case of interspecific nest appropriation by the Eared Dove (Zenaida auriculata) on a nest of the Creamy‐bellied Thrush (Turdus amaurochalinus). The usurpation attempt resulted in the death of both nestlings, including a parasitic cowbird, despite forceful attempts by the thrushes to retake their nest and repeated attempts by the dove to feed the nestlings. We believe that the loss of the dove offspring from a nest in a neighboring tree could have triggered this behavior, which may be a hormonal byproduct caused by the recent loss of their own offspring, similar to what has been observed in Emperor Penguins (Aptenodytes fosteri).Fil: Segura, Luciano Noel. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez, Exequiel. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jauregui, Adrian. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
A completely leucistic Rufous-bellied Thrush (Turdus rufiventris) breeding successfully in central-east Argentina
Full text linkLeucism is a color aberration characterized by the absence of pigmentation which can either be partial or complete. Abnormally colored birds have reduced chances of survival and mating success compared to normally colored individuals. We present a documented record of a complete leucistic adult Rufous-bellied Thrush (Turdus rufiventris) breeding successfully in Cariló, centraleast Argentina. In the winter of 2016 we observed a completely white thrush. In the subsequent spring we observed it collecting food and delivering it to two fledglings, which were normally colored. The adult thrush survived its own post-fledging period despite its increased predation risk due to conspicuousness, managed to get a breeding pair and breed successfully. Since reports of abnormally colored birds breeding in wild populations are rare, we emphasize the importance of making this information available.Fil: Colombo, Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Gonzalez, Exequiel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Jauregui, Adrian. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Segura, Luciano Noel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
Colección de nidos de aves de Argentina: una fuente inexplorada de investigación
Full text linkLos estudios basados en colecciones de nidos de aves tienen varias ventajas para los investigadores; por ejemplo, establecer comparaciones directas evitando tener que ubicar los nidos en el campo o preservar en el tiempo el material del nido. No obstante, el acceso a las colecciones de nidos suele ser un problema para los investigadores, debido a la falta de información de sus contenidos. En este trabajo se presentan los contenidos de la colección de nidos de aves del Museo de La Plata, con el objetivo de incentivar un mayor uso de este valioso recurso. La colección cuenta con 435 nidos correspondientes a 101 especies de 30 familias. Se destacan nidos de especies con muy poca información de su biología reproductiva como el Bailarín Castaño (Piprites pileata), la Viudita Plomiza (Knipolegus cabanisi), el Burrito Negruzco (Porzana spiloptera), el Flautín (Schiffornis virescens) y la Mosqueta Cara Canela (Phylloscartes sylviolus). En la colección están bien representadas las especies de la ecorregión Pampeana (242 nidos), así como también el Bosque Patagónico (58 nidos), las Yungas (30 nidos) y la Selva Paranaense (27 nidos).Studies based on avian nest collections had several advantages for researchers, such us to establish direct comparisons avoiding locating the nests in the field or the preservation over time of the nest material. Nonetheless, access to nest collections usually becomes an issue for researchers, due to the lack of information of their contents. This study present the contents of the La Plata Museum nest collection in order to encourage a greater use of this valuable resource. The collection holds 435 nests built by 101 species in 30 families. Some nests stand out due to the lack of knowledge about the breeding biology of the species, like the Black-capped Piprites (Piprites pileata), the Plumbeous Black-Tyrant (Knipolegus cabanisi), the Dot-winged Crake (Porzana spiloptera), the Greenish Schiffornis (Schiffornis virescens) and the Bay-ringed Tyrannulet (Phylloscartes sylviolus). In the collection are well represented the species of Pampas ecoregion (242 nests), as well as Patagonian forests (58 nests), Yungas (30 nests) and Paranaense forests (27 nests).Fil: Quintela, Facundo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Gonzalez, Exequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Segura, Luciano Noel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentin
High levels of natal philopatry and no difference in reproductive success between philopatric and non-philopatric songbirds breeding in a native forests of east-central Argentina
No full textPhilopatric birds have a number of advantages when breeding in familiar habitats, such as learning the locations of food, efficient movement throughout the breeding area, or effective escape from predators. However, few investigators have examined the possible effect of site familiarity on reproductive success, even less for Neotropical songbirds. We studied a breeding population of Masked Gnatcatchers (Polioptila dumicola) and Vermilion Flycatchers (Pyrocephalus rubinus), two south temperate songbirds, and examined the possible reproductive benefits of natal philopatry. In our population, 13.9% and 6.9% of breeding adults, respectively, for Masked Gnatcatchers and Vermilion Flycatchers, were philopatric. We found no difference in the breeding success between philopatric and non-philopatric individuals. Our results showed higher levels of philopatry for both species than previously reported for other songbirds. Because the remnants of native forests in our study area were located within a matrix of highly disturbed habitats, these intermediate-to-high values of natal philopatry could be linked to the structural characteristics of the forest that may force birds to use the few suitable forest patches available in the area.Fil: Rozas Sia, Mauro Gabriel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Gonzalez, Exequiel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Segura, Luciano Noel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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