Ornitología Neotropical (E-Journal)
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PRIMERA DESCRIPCIÓN DEL NIDO Y HUEVOS DEL SEMILLERO PARAMUNO (CATAMENIA HOMOCHROA)
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COMPOSICION DE LA DIETA POST‐REPRODUCTIVA DE LA GAVIOTA COCINERA (LARUS DOMINICANUS) EN EL LAGO NAHUEL HUAPI, PATAGONIA ARGENTINA
Get PDFResumen ∙ La Gaviota Cocinera (Larus dominicanus) es una especie generalista que ha expandido e incrementado sus poblaciones en Patagonia. Su capacidad para explotar el consumo de fuentes de alimento de origen antrópico, es uno de los factores que ha permitido esta expansión, tanto en ambientes marinos como dulceacuícolas. La colonización de nuevos ambientes puede afectar directa o indirectamente a otras especies, ya sea por predación, competencia o cleptoparasitismo. Por esto último, resulta necesario conocer la composición de la dieta de las poblaciones de Gaviota Cocinera asentadas recientemente en ambientes continentales de agua dulce. El presente estudio brinda información de la dieta post‐reproductiva de la especie en un ambiente dulce‐acuícola patagónico. Se recolectaron 75 pellets regurgitados de la especie en el complejo Islas de La Guardia en el lago Nahuel Huapi, Provincia del Neuquén, Argentina, en la etapa post‐reproductiva de 2010 (21 de enero–27 de febrero 2011). Los desechos orgánicos de origen antrópico fueron los más frecuentes por pellet (58,6%), seguido por insectos (33,3%) y crustáceos (17,3%). En cuanto a la abundancia, los insectos (48,9%) y los desechos orgánicos (24,7%) fueron los ítems más importantes. Para constatar el origen de los pellets y analizar las proporciones etarias fueron censados adultos, subadultos y juveniles en el área antes de cada recolección de pellets regurgitados. El promedio de adultos fue 77,1 (ES = 40,6, rango = 43–155), el de sub‐adultos 6,3 (ES = 3,6, rango = 3–15) y el de juveniles fue de 3 individuos (ES = 2,8, rango = 1–9). La utilización de desechos orgánicos antrópicos por los adultos de Gaviota Cocinera en este ambiente, demostró ser igualmente importante en los períodos post‐reproductivo y reproductivo, y la escasez de juveniles en los censos sugiere la utilización diferencial de recursos. Este es el primer estudio sobre la dieta post‐reproductiva de la Gaviota Cocinera en un ambiente dulce‐acuícola. Abstract ∙ Diet of post‐breeding Kelp Gulls (Larus dominicanus) in Nahuel Huapi Lake, Patagonia Argentina The Kelp Gull (Larus dominicanus) is a generalist species undergoing a process of range expansion and population increase in Patagonia. The ability of utilizing anthropogenic waste is one of the factors that might have enabled this expansion into freshwater environments. Colonization of new environments could affect directly or indirectly other species, throughout predation, competence or kleptoparasitism. In this sense, it is necessary to understand the diet of the recent populations settled in continental freshwater environments. The current study provides information about the post‐breeding diet in a freshwater environment in Patagonia. We collected 75 regurgitated pellets in De La Guardia Islands during the post‐breeding period between January and February 2010 in Nahuel Huapi Lake, Neuquén province, Argentina. Organic human refuse was the most frequent item (58.6%), followed by insects (33.3%) and crustaceans (17.3%). Insects (48.9%) and human refuse (24.7%) were the most important prey items in terms of abundance. Pellets were mainly cast by adults (mean number of adults = 77.1 per visit, SD = 40.6, range = 43–155), which were much more abundant than sub‐adults (mean = 6.3 per visit, SD = 3.6, range = 3–15) or juveniles (mean = 3, SD = 2.8, range = 1–9). Human refuse importance in the diet of the Kelp Gull was as important during post‐breeding as during breeding season. This is the first report of the post‐breeding diet composition of the Kelp Gull in a continental freshwater environment
WHITE‐CROWNED MANAKIN (DIXIPHIA PIPRA) USE OF SPACE IN THE ECUADORIAN AMAZON
Get PDFAbstract ∙ Animal patterns of space use have fundamental consequences for ecological processes such as animal‐ mediated seed dispersal. This study examines the use of space of an understory frugivore: the White‐crowned Manakin (Dixiphia pipra) during the non‐breeding season at Tiputini Biodiversity Station in Ecuador. We radio‐tracked seven individuals of different sexes and ages. We found that White‐crowned Manakins have relatively small home ranges varying from 1.19 to 5.73 ha. The home ranges of male juveniles (2.25 ± 0.62 SE) were larger than that of the adult males (1.20 ± 0.01 SE), but smaller than those of females (4.27 ± 0.77 SE). Females and second‐year males were found to perform more long distance flights outside their core home range than hatch‐year or adult males. These movement differences suggest that they disperse seeds longer distances and more evenly across their home range. Adult and hatch‐year males appear to perform more short distance seed dispersal events. We argue that these contributions are complementary, and that White‐crowned Manakins are key dispersal agents that have a significantly influence in the structure and composition of understory plant communities in the Amazon rainforest.Resumen ∙ Uso de espacio del Saltarín Coroniblanco (Dixiphia pipra) en la Amazonía Ecuatoriana Los patrones de uso espacial utilizados por animales tienen consecuencias fundamentales en procesos ecológicos, tales como la dispersión de semillas. Este estudio examina el uso espacial de una especie frugívora de sotobosque: el Saltarín Coroniblanco (Dixiphia pipra) durante el ciclo no‐reproductivo en la Estación de Biodiversidad de Tiputini en Ecuador. Seguimos por radio telemetría a siete individuos de diferentes sexos y edades. Encontramos que el Saltarín Coroniblanco tiene un rango de hogar relativamente pequeño, variando entre 1,19 a 5,73 ha. El rango de hogar de los machos juveniles (2,25 ± 0,62 EE) es más grande que el de los machos adultos (1,20 ± 0,01 EE), pero más pequeño que el de las hembras (4,27 ± 0,77 EE). El estudio encontró que las hembras y los machos de segundo año realizaron vuelos más largos fuera del núcleo de su rango de hogar, comparado con machos juveniles del año o machos adultos. Estas diferencias sugieren que podrían dispersar semillas a mayores distancias y de manera más homogénea a lo largo de su rango de hogar. Los machos adultos y los juveniles del año parecen llevar a cabo eventos de dispersión de semillas a distancias más cortas. Nosotros argumentamos que estas contribuciones son complementarias y que los Saltarines Coroniblancos son agentes de dispersión claves, influenciando considerablemente la estructura y la composición de las comunidades de plantas del sotobosque en el bosque tropical lluvioso de la Amazonía Ecuatoriana.
CARACTERIZACIÓN AMBIENTAL Y ESTACIONAL DEL ENSAMBLE DE AVES ACUÁTICAS DE LA MESETA DEL LAGO STROBEL, PATAGONIA, ARGENTINA
Get PDFRESUMEN ∙ Los humedales se encuentran entre los ecosistemas más relevantes debido a su papel como reservorios de biodiversidad y su rol ecológico es particularmente importante en las regiones áridas. Este estudio analiza la estructura de los ensambles de aves acuáticas de la Meseta del Lago Strobel, un sitio importante para la conservación de las aves en Patagonia. Se analizó la composición de especies, abundancia, riqueza y diversidad específica considerando variaciones estacionales y el uso de ambientes particulares. Durante cinco años se realizaron 243 conteos en 102 lagunas, en las estaciones primavera, verano y otoño. Se analizó el uso de ambientes en base a una clasificación previa que definió cuatro tipos de lagunas: grandes no vegetadas (GNV), grandes vegetadas (GV), pequeñas vegetadas (PV) y turbias (TB). Se registraron 18 especies de aves acuáticas, pertenecientes a 5 familias y 12 géneros. La mayor abundancia de aves se observó en primavera y en lagunas GV, y el máximo de diversidad se registró en verano en las lagunas TB. La familia Anatidae dominó los ensambles en todos los tipos de lagunas y estaciones del año analizadas, tanto en términos de abundancia como en frecuencia de ocurrencia. Dos especies amenazadas incluidas en este estudio (Macá Tobiano, Podiceps gallardoi y Flamenco Austral, Phoenicopterus chilensis) y un migrante Neártico (Falaropo Común, Phalaropus tricolor) formaron parte de las especies importantes del ensamble. Este estudio muestra la relevancia de las características particulares de los ambientes en la conformación y dinámica temporal de los ensambles de aves acuáticas de la meseta de lago Strobel. Las lagunas de la meseta constituyen un mosaico dinámico con importantes variaciones interanuales en la abundancia de lagunas y sus características limnológicas. En este contexto las aves dependerían de la red de lagunas más que de cuerpos de agua individuales. Las acciones de manejo dirigidas a la conservación deberían contemplar al sistema completo de lagunas, considerando además su variación temporal.ABSTRACT ∙ Spatial and seasonal characterization of the waterbird assemblage of The Strobel Plateau, Patagonia, Argentina Wetlands are key ecosystems due to their role as biodiversity reservoirs, and are particularly important in arid environments. We studied the waterbird assemblage structure of the Strobel Plateau, an important bird conservation area in southern Patagonia. The effects of spatial and seasonal variation on species composition, abundance, richness, and diversity were analyzed based on 243 counts in 102 shallow lakes during spring, summer, and autumn. Habitat utilization was assessed based on a previous classification which defined 4 different types of lakes: large non‐vegetated (GNV), large vegetated (GV), small vegetated (PV), and turbid (TB). We recorded 18 waterbird species comprising five families and 12 genera. Maximum waterbird abundance was observed in spring in the GV lakes, while highest diversity appeared in summer at the TB lakes. Ducks and swans (family Anatidae) dominated the assemblages in all kind of lakes and during all evaluated seasons, both in abundance and frequency of occurrence. The threatened species (Hooded Grebe, Podiceps gallardoi; Chilean Flamingo, Phoenicopterus chilensis) and the only Neartic migrant (Wilsons’s Phalarope, Phalaropus tricolor) recorded were an important part of the assemblage. This study shows the importance of habitat characteristics in determining the structure of waterbird assemblages and their temporal dynamics in Lake Strobel Plateau. The plateau lakes are a dynamic mosaic showing marked seasonal variation in number and limnological characteristics. In this context, aquatic birds may depend more on the network of lakes than on individual lakes. Thus, conservation management actions need to take into account the lake system as a whole and its temporal patterns of variation
PARÁSITOS SANGUÍNEOS DE MALARIA Y GÉNEROS RELACIONADOS (ORDEN: HAEMOSPORIDA) EN AVES DE MÉXICO: RECOMENDACIONES METODOLÓGICAS PARA CAMPO Y LABORATORIO
Get PDFMalaria parasites and related genera (order: Haemosporida) in birds from Mexico: methodological recommendations for the field and laboratory. – Parasites from the order Haemosporida (phylum: Apicomplexa) are transmitted by blood-sucking insects (order Diptera) and infect a wide array of amphibians, reptiles, birds, and mammals. Four genera of these parasites have been reported in birds: Plasmodium, Haemoproteus, Fallisia, and Leucocytozoon. Most studies on this group of parasites have been conducted in North America and Europe. In the Neotropical region studies are still scarce but have recently increased. In Mexico, our literature survey reveals the existence of 17 published studies. However, in many of these studies we detected shortcomings in the correct preparation of blood smears, such as lack of fixing in methanol and inadequate staining, which makes parasite identification difficult and renders blood smears useless as material for museum collections. Furthermore, we find similar mistakes in more recent unpublished studies (conference presentations, theses). Here we make methodological recommendations for the correct preparation and processing of blood smears both in the field and the laboratory. Our aim is to provide practical help to ornithologists and parasitologists interested in working with this group of parasites, in order to obtain high quality material that can subsequently be deposited at museum collections
THE DIET OF UPLAND SANDPIPERS (BARTRAMIA LONGICAUDA) IN MANAGED FARMLAND IN THEIR NEOTROPICAL NON-BREEDING GROUNDS
Get PDFThe Upland Sandpiper (Bartramia longicauda) is a migratory shorebird that inhabits grasslands at the breeding and non-breeding grounds. The trophic ecology of the species is poorly known, but it is thought to be insectivorous. In this study, we describe the diet of the Upland Sandpiper and its temporal variation in grasslands of northern Uruguay. From 2008 to 2012, we collected 67 feces at nine different sites in the Departments of Salto and Paysandú. The diet consisted mainly of insects (present in 98% of the feces) belonging to three orders: Coleoptera (in 80% of feces), Orthoptera (79%), and Hymenoptera (48%). Consumption of Orthoptera and Hymenoptera varied among years. Plant remains and stones were also recorded in feces. Vegetation may have been consumed secondarily while stones could be used in food processing in the gizzard. Our study demonstrates that Upland Sandpipers are diet generalists and probably forage opportunistically, depending on resource availability and focusing on the most abundant prey items
SEXUAL DIMORPHISM IN A COOPERATIVE BREEDING THRAUPID (WHITE‐BANDED TANAGER, NEOTHRAUPIS FASCIATA): THE RELEVANCEOF THE BLACK MASK
Get PDFABSTRACT ∙ Sexual dimorphism is common among birds, and is often caused by sexual selection. The detailed characterization of sexual dimorphism in a species is essential to propose and test hypotheses about the mechanisms responsible for its origin and maintenance. In this context, we examined the sexual size and plumage dimorphism in the White‐banded Tanager (Neothraupis fasciata) based on wild individuals sexed using DNA‐based techniques in seven different localities in the Brazilian savanna (Cerrado). Based on eight morphometric variables, we found that males were on average larger than females, and found statistically significant differences for some morphometric variables in three localities studied. Sexual dimorphism in plumage coloration was restricted to the size of the black mask, which extended to the lores in males and was limited to the auriculars in females. Thus, our results showed that the White‐banded Tanager exhibits dimorphism in size and plumage, indicating that sexual dimorphism in this species seems more intricate than it has been described in literature. We also emphasize that the extension of the black mask is the best trait for sexing this species, and it can also be applied to immatures. Finally, we point out some aspects that should be investigated to better understand the evolution and maintenance of the sexual dimorphism in the White-banded Tanager.RESUMO ∙ Dimorfismo sexual em um traupídeo com reprodução cooperativa (tiê‐do‐cerrado, Neothraupis fasciata): a relevância da máscara preta O dimorfismo sexual é comum entre as aves e é frequentemente causado pela seleção sexual. A caracterização do dimorfismo sexual de uma espécie é essencial para propor e testar hipóteses relacionadas aos mecanismos responsáveis pela sua origem e manutenção. Neste contexto, examinamos o dimorfismo sexual de tamanho e plumagem no tiê‐do‐cerrado (Neothraupis fasciata) em sete localidades diferentes distribuídas nas savanas brasileiras (Cerrado) com base em indivíduos sexados por técnica molecular. Considerando as oito variáveis morfométricas avaliadas, observamos que os machos foram em média maiores do que as fêmeas, e encontramos diferenças estatisticamente significativas para algumas variáveis morfométricas em três localidades amostadas. O dimorfismo sexual de plumagem nessa espécie está relacionado com o tamanho da máscara preta, que se estende até o loro nos machos e está limitada às auriculares nas fêmeas. Os resultados mostram que o tiê‐do‐cerrado apresenta tanto dimorfismo de tamanho quanto de plumagem, indicando que o dimorfismo sexual nessa espécie parece mais complexo do que tem sido descrito na literatura. Ressaltamos ainda que a extensão da máscara preta é a melhor característica para identificar o sexo dos indivíduos desta espécie, inclusive porque esta característica pode ser aplicada em imaturos. Finalmente, nós apontamos alguns aspectos que podem ser investigados para melhor entender a evolução e manutenção do dimorfismo sexual no tiê‐do‐cerrado