Ornitología Neotropical (E-Journal)
Not a member yet
359 research outputs found
Sort by
VARIACIÓN DE LA ESTRUCTURA DEL CANTO DEL GORRIÓN DE COLLAR RUFO (ZONOTRICHIA CAPENSIS) A LO LARGO DE UN GRADIENTE URBANO EN EL SUROESTE DEL PERÚ
Get PDFEl canto cumple un importante rol en la ecología y comportamiento de las aves. Entender los procesos que alteran la producción y transmisión del canto es fundamental para dilucidar su respuesta a cambios en el ambiente. En este contexto, los ambientes urbanos representan sistemas de estudio útiles para entender esta adaptación. Examinamos la estructura del canto del Gorrión de Collar Rufo (Zonotrichia capensis) a lo largo de un gradiente urbano en la ciudad de Arequipa, en el suroeste del Perú. Obtuvimos 240 cantos en total de 80 individuos distribuidos en áreas urbanas, suburbanas, rurales y silvestres, y analizamos la frecuencia máxima, frecuencia mínima y duración de la introducción y del trino. Encontramos diferencias significativas en la estructura espectral (frecuencia mínima), a lo largo del gradiente urbano. Las frecuencias mínimas de la introducción y trino fueron más altas en áreas más urbanizadas. Mientras que las frecuencias máximas y duraciones de ambas partes del canto no variaron. Efectos del ruido antropogénico o de las estructuras verticales de concreto de áreas muy urbanizadas, podrían explicar la variación en el canto de esta especie común de la ciudad de Arequipa. Así mismo, este estudio muestra que la frecuencia mínima en esta especie es el parámetro más susceptible de presentar variación en ambientes con distintos grados de urbanización
DOES THE FOREST OR THE ANTHROPOGENIC BUILDING DISTANCE INFLUENCE GREAT KISKADEE (PITANGUS SULPHURATUS) NESTING SITE SELECTION?
No full textHuman settlements expansion has generated significant changes in natural ecosystems. The consequences in the avifauna are varied, among them, changes in the availability of natural and artificial sites to build nests. Some species can nest on perches built by humans; however the characteristics of the perch that are selected are unknown. Our objective with this work is to determine if the presence of nests of the Great Kiskadee (Pitangus sulphuratus) on electricity posts, depends on the proximity of the post to a building inhabited by humans or whether it depends on the proximity to a forest patch. We counted and described all the posts present in 30 km of gravel and asphalt roads. We classified each post according to the number of plates, electrical transformers and lights. We also checked if each post had or not a nest of under study species. Using a GPS, We measured the distance between en the post and the forest and between en the post and the nearest building. The presence of nests was more frequent in posts far from a forest and near from a building. In addition, the characteristics of the post influence the presence of Great Kiskadee nests in posts
MINIATURE GPS DATA LOGGERS REVEAL HABITAT AFFILIATIONS AND MOVEMENT OF VEERY (CATHARUS FUSCESCENS) DURING THEIR FIRST NON-TRANSIENT PERIOD IN SOUTH AMERICA
No full textThe ecology of Nearctic-Neotropical migrant songbirds in South America is largely unexplored. We used miniature global positioning system (GPS) data loggers to determine the broad habitat associations of nine Veeries (Catharus fuscescens) during their first non-transient period in South America. Because Veeries undertake an intratropical migration between two separate non-transient periods, the habitat used by settled birds in South America cannot not be determined from field observation or the capture of single unmarked individuals. Using satellite images, we examined coarse habitat characteristics at GPS positions from the tagged birds during their first non-transient period (December – February). We also examined habitat descriptions from existing records (e.g., published literature, museum records) of multiple birds from single sites that we consider settled individuals. All records we accepted as birds settled during their first non-transient period, including birds we tagged, were associated with stunted forest on nutrient poor soils primarily on elevated cerrado and white sand enclaves (~200 – 750 m) on the Brazilian Shield in southern Amazonia (cerrado, cerradão, savana metalófita – canga, campinarana, sartenejal). Notably, these uncommon forest communities are geographically limited and severely threatened due to anthropogenic conversion. Therefore, because of restricted habitat availability and the species’ recent population decline, we believe the Veery’s current global conservation status should be reconsidered. Following Nearctic-Neotropical migration, tagged individuals exhibited three behaviors prior to intratropical migration: (1) a prolonged stationary period at a single site, (2) shorter stationary periods with relocation events, (3) apparent continual movement. Our results have significant importance in terms of understanding the ecology and conservation needs of this declining species and demonstrate the utility of GPS loggers in tracking songbirds through dense tropical vegetation in remote and inaccessible regions of South America
OCUPACIÓN DE LA COMUNIDAD DE BÚHOS EN UN BOSQUE TEMPLADO EN MEXICO
No full textLos bosques templados son de los ecosistemas más amenazados. Las alteraciones en los bosques modifican la estructura de la vegetación y provoca cambios en la distribución y abundancia de las especies. Los búhos son elementos importantes en los bosques y estudiar su ocupación permitirá entender su abundancia y las variables ambientales asociadas. Para estimar los índices de ocupación de cinco especies de búhos en el área, se recorrieron tres transectos lineales en 2012 y 2015 en el Área Natural Protegida Piedra Canteada, Tlaxcala México. Asimismo se establecieron parcelas para medir variables estructurales de la vegetación y fisiográficas. Tres especies presentaron mayores índices de ocupación en ambos años: Aegolius acadicus; Psiloscops flammeolus y Bubo virginianus. Mientras que Tyto alba y Megascops kennicottii presentaron menores índices de ocupación. Hubo variables asociadas a los índices de ocupación de B. virginianus como el número de troncos caídos y a la fuente de agua más cercana. Las variables de los modelos de ocupación se asociaron con el disturbio de la vegetación, las distancias a las fuentes de agua y a asentamientos humanos. Estos resultados proveen la primera aproximación a los patrones de ocupación y asociación a las variables de la vegetación de las especies de búhos en bosques templados en el noroeste de Tlaxcala, México
UNEXPECTED LACK OF EFFECT OF THE INVASIVE AMERICAN MINK ON NESTING SURVIVAL OF FOREST BIRDS
Get PDFNest predation by invasive mammalian predators can cause major impacts on native bird populations. The American mink (Neovison vison) was recently introduced on Navarino Island in southern Chile. The mink established as a new terrestrial mesopredator on the island with documented impacts on waterfowl breeding success. However, little is known about mink effects on forest bird’s reproduction. Here, we investigated nest-predation rate by native predators and the invasive mink on open-cup nesting forest birds by using artificial and natural nests. In six different plots, we deployed a grid (7 x 2) of 14 artificial nests spaced by 50 m and at random heights from the ground. We used camera traps in each nest to identify predators. At each plot, we estimated predator relative abundance using camera traps, Sherman traps, and bird point counts. We estimated nest survival probability as a function of nest age, concealment, distance to the river, and nest height. Additionally, we monitored 43 natural nests of five open-cup nesting bird species. Contrary to expected, mink was not a main predator of nests, depredating only one natural nest. The native raptor Chimango Caracara (Milvago chimango) was the main nest predator, preying on 39.8% artificial nests and 27.0% natural nests. We also found evidence that Chimango Caracara learned to associate the artificial nests with the egg reward. We argue that the lower abundance of mink in the forest and a mismatch between mink peak activity patterns and bird breeding phenology can result in low depredation. Mink impacts, however, may be more pervasive in summer months and on fledglings when mink activity peaks, and more research should be conducted to assess these questions. Our results are valuable to better understand mink impacts on biodiversity and to prioritize conservation actions on species more severely affected
LIVE FENCES HAVE GREATER DIVERSITY OF BIRD ASSEMBLAGES THAN GALLERY FORESTS IN HUMAN-MODIFIED ECOSYSTEMS
Get PDFAnthropogenic activities have led to changes in land use resulting in fragmented areas with a reduction of biodiversity and ecosystem services. Gallery forests and live fences are common elements in Neotropical agricultural landscapes that could contribute to the conservation of bird species and the services they provide. However, we need to better understand how different tree cover types influence bird assemblages in order to conserve biodiversity. I analysed the diversity of bird assemblages in space and time across two cover types in three agricultural-livestock farms in Guanacaste, Costa Rica. Bird assemblages were sampled during 2019 using transects, covering both the dry and rainy season. I estimated richness and relative abundance of bird assemblages at each tree cover type and site. To characterize vegetation structure, I calculated plant richness, diameter at breast height and tree height. Patterns in bird diversity changed at a spatial scale, whereas remained similar in time. Bird assemblages had consistently higher richness and abundance in live fence than in gallery forest in the three study sites. In addition, live fences resulted in a less structural complexity compared to gallery forest, as indicated by decreased plant richness and tree height. My results show that live fences play an important role for birds, allowing for more diverse avian assemblages in human-modified ecosystems. Although live fences are less structurally complex and may offer less suitable habitats for birds than gallery forests, they might provide complementary food resources and act as stepping-stones for both resident and migratory bird species. Thus, live fences may perform as corridors for birds increasing connectivity in rural landscapes, which make them an essential tool for bird conservation
FREQUENCY OF AVIAN HAEMOSPORIDIAN PARASITES IN BIRDS FROM MARGARITA AND COCHE ISLANDS, VENEZUELA
Get PDFBy amplifying and sequencing a mitochondrial DNA barcode (cytb), we screened the frequency of haemosporidian parasites (Haemoproteus, Plasmodium, Leucocytozoon) in 366 birds (23 species) from Margarita and Coche islands, Venezuela. In Coche (N = 24), none of the birds were infected, while in Margarita (N = 342) 13 individuals were (3.8%). The frequency of these parasites in endemic bird subspecies was more than double than in non-endemic forms (endemics = 7.3% vs non-endemic = 3.1%, N = 342), but it was not statistically significant. We found eight parasite lineages, four of which are novel (COLPAS09, COLSQU03, COLSQU04, HYPRUF01). COLSQU03, recorded in a dove (Columbina squammata), falls within the Haemoproteus (Parahaemoproteus) subgenus. This was unexpected because a strong signal of co-speciation has been found between Columbidae and the Haemoproteus (Haemoproteus) subgenus, suggesting a host-switching event
MORPHOLOGICAL VARIATION IN THE TIT-LIKE DACNIS (XENODACNIS PARINA): A CALL TO REVISE THE TAXONOMIC STATUS OF ECUADOR’S POPULATION
Get PDFXenodacnis is a specialized high Andean bird genus of which males are larger and show different feather coloration from females. However, sexual dimorphism has not been analyzed in detail yet. Distributed in Ecuador and Peru, Xenodacnis have long been considered as a single species genus, with three subspecies. Discovered in the 1980`s, the population in Ecuador has not been given a taxonomic identity so far. Thus, this study gathers morphological data from Xenodacnis throughout its distribution, and confirmed the morphological differences between sexes: males are significantly larger and heavier than females; but without consistent differences in bill size. Between populations, the research shows smaller individuals in the south, with size increasing towards the northernmost Ecuadorian populations. These results suggest that the taxonomy of the genus Xenodacnis should be revised and the population from Ecuador should have a proper taxonomic identity different from all previously described members of the genu
CONSERVATION OF THE ORINOCO GOOSE (NEOCHEN JUBATA) IN THE MIDDLE ARAGUAIA RIVER, TOCANTINS, BRAZIL.
Get PDFThe Orinoco goose, (Neochen jubata) is a grazing herbivore of open habitats that was once widely distributed in tropical South America. Centuries of overhunting and habitat loss have reduced it to widely scattered remnant populations; it is categorized as Near Threatened globally. Within the Cerrado biome, the Middle Araguaia River houses the largest remnant population. In August 2017, a study was started to assess the situation of the Orinoco Goose in the regions of Araguaia National Park, Cantão State Park, and adjacent rice fields. We conducted counts from an aerial census (a 700 km transect), monthly boat censuses (40 km) and land censuses in rice plantations. The aircraft census counted 367 individuals in August 2017, while monthly monitoring of a stretch of the lower Javaés River over more than two years showed a seasonal population variation associated with the flood regime, with the species virtually disappearing during the flood period between January and April when river beaches are submerged. During this period, large flocks of about 1,000 Orinoco Geese were discovered not far away, concentrated in small stretches of rice plantation agro-systems in the region. This behavioral seasonal concentration makes the species susceptible to poisoning and epizootic diseases. The findings suggest the need to re-categorize the Orinoco Goose population of the Middle Araguaia River as “Threatened” for the State of Tocantins due to the decline observed in the last 10 years, the maximum estimated population size, and the significant seasonal concentrations in a restricted area. At the same time, it is necessary to develop an action plan for its conservation in the surroundings of Ilha do Bananal, and throughout Brazil, where its threat status must be reviewed
NOTES ON THE DISPLAYS AND POSSIBLE LEK BEHAVIOR OF THE FIERY TOPAZ (TOPAZA PYRA) (APODIFORMES: TROCHILIDAE)
Get PDFThe genus Topaza comprises two species of large hummingbirds with allopatric distributions in Amazonia. Lek behavior has already been described in almost 30 species of hummingbirds, including Crimson Topaz Topaza pella, but not for Fiery Topaz T. pyra. We describe male displays by T. pyra and how these might be possibly correlated to lek behavior, based on observations at different locations in Ecuador, Colombia, and Brazil. These behaviors are compared to the previously described behavior of T. pella and other hummingbirds, but we also describe an extremely unusual upside-down hanging behavior during male to male interactions. Furthermore, some of our observations evidence an apparent tendency for more than one male to converge on a specific perch, perhaps to compete for dominance within a group of otherwise more dispersed, probably linear song territories.