884 resultados para INSECTIVOROUS BIRDS


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Biologia Animal - IBILCE

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Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.

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Dietary data from a large sample of woodcreepers (16 spp., n?=?139), revealed that six species of dendrocolaptids occasionally feed upon lizards and frogs. These birds, which are mainly insectivorous, encounter and feed on lizards while perching on tree trunks, probably in association with army-ant swarm feeding behaviour. Frog intake may be related to declines in the abundance of invertebrate prey. The bones recovered were identified as one small species of gecko, Gonatodes humeralis, and at least one anuran. We estimate that in the entire sample, about eight lizards and two frogs were ingested. The partially digested gecko material allows determination of which bones are more resistant to digestion, although it is possible that these elements were differentially retained in the stomach. These elements correspond to the more frequently preserved bones in the fossil record of geckos, indicating that the same portions of the skeleton persist under the processes of both digestion and fossilization.

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Avian ecosystem services such as the suppression of pests are considered being of high ecological and economic importance in a range of ecosystems, especially in tropical agroforestry. But how bird predation success is related to the diversity and composition of the bird community, as well as local and landscape factors, is poorly understood. The author quantified arthropod predation in relation to the identity and diversity of insectivorous birds, using experimental exposure of artificial, caterpillar-like prey on smallholder cacao agroforestry systems, differing in local shade management and distance to primary forest. The bird community was assessed using both mist netting (targeting on active understory insectivores) and point count (higher completeness of species inventories) sampling. The study was conducted in a land use dominated area in Central Sulawesi, Indonesia, adjacent to the Lore Lindu National Park. We selected 15 smallholder cacao plantations as sites for bird and bat exclosure experiments in March 2010. Until July 2011, we recorded several data in this study area, including the bird community data, cacao tree data and bird predation experiments that are presented here. We found that avian predation success can be driven by single and abundant insectivorous species, rather than by overall bird species richness. Forest proximity was important for enhancing the density of this key species, but did also promote bird species richness. The availability of local shade trees had no effects on the local bird community or avian predation success. Our findings are both of economical as well as ecological interest because the conservation of nearby forest remnants will likely benefit human needs and biodiversity conservation alike.

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Swiftlets are small insectivorous birds, many of which nest in caves and are known to echolocate. Due to a lack of distinguishing morphological characters, the taxonomy of swiftlets is primarily based on the presence or absence of echolocating ability, together with nest characters. To test the reliability of these behavioral characters, we constructed an independent phylogeny using cytochrome b mitochondrial DNA sequences from swiftlets and their relatives. This phylogeny is broadly consistent with the higher classification of swifts but does not support the monophyly of swiftlets. Echolocating swiftlets (Aerodramus) and the nonecholocating "giant swiftlet" (Hydrochous gigas) group together, but the remaining nonecholocating swiftlets belonging to Collocalia are not sister taxa to these swiftlets. While echolocation may be a synapomorphy of Aerodramus (perhaps secondarily lost in Hydrochous), no character of Aerodramus nests showed a statistically significant fit to the molecular phylogeny, indicating that nest characters are not phylogenetically reliable in this group.

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The diet study of birds has contributed historically as a model for use to understanding ecological patterns and strategies used by several other groups of vertebrates, which are observed in season patterns and temporal availability of resources, and other. This study has as objective generate information concerning the diet of insectivorous birds during rainy season and dry season, as well as analyze Index food importance, niche overlap, niche breadth, electivity, and seasonal availability of prey. The study was conducted in a fragment of about 270 ha (center coordinates and 5 º 53'S 35 ° 23'W). The sampling of birds occurred between March 2008 and December 2009 in three pre-established trails. Catches of birds were performed using 10 mist nets placed in line, where each trails was sampled once a month. Samples of pellets were obtained by means of tartar emetic. Sampling of availability of prey occurred between February 2009 to December 2009. We used two methods of sampling (pitfall traps and Shake cloths). We captured 269 individuals of 21 species of insectivorous birds. We collected 4116 invertebrates of which 3259 in the rainy season and 857 in the dry season. We obtained 174 samples stomach, where 10 species were exclusively insectivorous diet, nine fed on insect/plant material, an insect/plant material/vertebrate and one for insect/vertebrate. During the rainy season was observing difference between the consumption of items with higher food importance. The Coleoptera was item with higher food importance (73%), followed by Formicidae (7%) and Araneae (6%). During the dry season, no difference was found difference between the consumption of items with higher food importance. The Coleoptera was item with higher food importance (34%), followed by seeds (29%) and Formicidae (18%). The highest levels of niche overlap occurred during the rainy season, while the dry season was characterized by high levels of niche 11 segregation. This indicates that the local insectivorous birds community was structured differently between periods. No was found correlation between the values of niche breadth to the mean weight of the body size. We observed seasonal patterns in prey availability, with the peak availability of invertebrates observed seasonal patterns in rainy season. The insectivorous birds selected the same species richness during both periods, showing a specialized diet. Thamnophilus pelzelni was the only species that had their diet influenced by seasonality. Regarding the overall diet of insectivorous birds, observed a high consumption of prey, whose food availability caused the birds could invest and increase their food resources

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Conceived to combat widescale biodiversity erosion in farmland, agri-environment schemes have largely failed to deliver their promises despite massive financial support. While several common species have shown to react positively to existing measures, rare species have continued to decline in most European countries. Of particular concern is the status of insectivorous farmland birds that forage on the ground. We modelled the foraging habitat preferences of four declining insectivorous bird species (hoopoe, wryneck, woodlark, common redstart) inhabiting fruit tree plantations, orchards and vineyards. All species preferred foraging in habitat mosaics consisting of patches of grass and bare ground, with an optimal, species-specific bare ground coverage of 30–70% at the foraging patch scale. In the study areas, birds thrived in intensively cultivated farmland where such ground vegetation mosaics existed. Not promoted by conventional agri-environment schemes until now, patches of bare ground should be implemented throughout grassland in order to prevent further decline of insectivorous farmland birds.

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The evolution and population dynamics of avian coronaviruses (AvCoVs) remain underexplored. In the present study, in-depth phylogenetic and Bayesian phylogeographic studies were conducted to investigate the evolutionary dynamics of AvCoVs detected in wild and synanthropic birds. A total of 500 samples, including tracheal and cloacal swabs collected from 312 wild birds belonging to 42 species, were analysed using molecular assays. A total of 65 samples (13%) from 22 bird species were positive for AvCoV. Molecular evolution analyses revealed that the sequences from samples collected in Brazil did not cluster with any of the AvCoV S1 gene sequences deposited in the GenBank database. Bayesian framework analysis estimated an AvCoV strain from Sweden (1999) as the most recent common ancestor of the AvCoVs detected in this study. Furthermore, the analysis inferred an increase in the AvCoV dynamic demographic population in different wild and synanthropic bird species, suggesting that birds may be potential new hosts responsible for spreading this virus.

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The Cerrado region still receives relatively little ornithological attention, although it is regarded as the only tropical savanna in the world considered to be a biodiversity hotspot. Cerradão is one of the least known and most deforested Cerrado physiognomies and few recent bird surveys have been conducted in these forests. In order to rescue bird records and complement the few existing inventories of this under-studied forest type in the state of São Paulo, we looked for published papers on birds of cerradão. Additionally we surveyed birds at a 314-ha cerradão remnant located in central São Paulo, Brazil, from September 2005-December 2006 using unlimited distance transect counts. Out of 95 investigations involving cerradão bird studies, only 17 (18%) investigations teased apart bird species recorded inside cerradão from those recorded in other physiognomies of Cerrado. Except for one study, no research found more than 64 species in this type of forest, a result shared within many regions from Brazil and Bolivia. Differences in species richness do not seem be related with levels of disturbance of landscape or fragment size. Considering all species recorded in cerradão in Brazil and Bolivia, a compilation of data accumulated 250 species in 36 families and 15 orders. In recent surveys at central São Paulo, we recorded 48 species in 20 families, including the Pale-bellied Tyrant-Manakin Neopelma pallescens, threatened in São Paulo, and the Helmeted Manakin Antilophia galeata, near threatened in the state and endemic to the Cerrado region. Among the most abundant species inside this fragment, none was considered to be neither threatened nor endemic.

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The present study is a report on the presence of Mycobacterium avium in four birds of the psittaciform order kept as pets. Anatomopathological diagnosis showed lesions suggestive of the agent and presence of alcohol-acid resistant bacilli (AARB) shown by the Ziehl-Neelsen staining. The identification of Mycobacterium avium was performed by means of PRA (PCR Restriction Analysis). DNA was directly extracted from tissue of the lesions and blocked in paraffin. The role of this agent in pet bird infection is discussed, as well as its zoonotic potential.

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Lamington National Park in Queensland, Australia is noted for its rainforest and is part of Australia’s fourteen World Heritage listed properties but no systematic study has been done of the importance of birds to its visitors. This study rectifies this situation. It is based on data from survey forms handed to visitors at an important site in this park and completed by visitors following their visit. This yielded 622 useable replies. These enabled us to establish the comparative importance of birds as an attraction to this site. Furthermore, logit regression is used to analyze and to identify factors that increase the likelihood of a visitor saying that birds are an important attraction. In addition, the relative importance to visitors of various attributes of birds at this site is established. These attributes include hearing birds, diversity of birds, seeing lots of birds, presence of rare birds, presence of brightly colored birds and physical contact with birds. Logit regression analysis is used to isolate independent variables that increase or decrease the likelihood that visitors find diversity of birds, brightly colored birds or physical contact with birds at this site to be important. For example, factors such as the level of education of visitors, their gender, knowledge of birds and conservation attitudes are statistically significant influences.

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Lamington National Park in Queensland, Australia is noted for its rainforest and is part of the World Heritage listed property but prior to this work, no systematic study has been done of the importance of birds to its visitors. This study is based on data from survey forms handed to visitors at an important site in the park and completed by visitors following their visit. It yielded 622 useable responses. These enabled us to establish the comparative importance of birds as an attraction to this site for this sample of visitors. Furthermore, logit regression is used to target analysis and to identify factors that increase the likelihood of a visitor saying that birds are an important attraction. In addition, the relative importance to visitors of various attributes of birds at this site is established. These attributes include hearing birds, diversity of birds, seeing lots of birds, presence of rare birds, presence of brightly coloured birds and physical contact with birds. Logit regression analysis is used to isolate independent variables that increase or decrease the likelihood that visitors find diversity of birds, brightly coloured birds or physical contact with birds at this site to be important. For example, factors such as the level of education of visitors, their gender, knowledge of birds and conservation attitudes and statistically significant influences. As a result of the analysis potential conflicts between different types of park visitors in relation to human interaction with birds are identified. Some potential ecological implications of human interactions with birds are modelled and discussed, and their economic conservation and biodiversity consequences are considered

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This case study concentrates on the extent of knowledge of members of the Australian public of Australia’s tropical bird species and their willingness to pay for their conservation. In order to place this issue in context, it first provides background information on the status of Australian bird species, focusing attention on species that occur in tropical Australia. Then, using survey results, this study considers the hypothesis that the public’s relative support for the conservation of different bird species depends on its comparative knowledge of their existence and status. Based on experimental results from a sample of residents of Brisbane, Queensland (Australia), it is found that their knowledge of bird species that occur exclusively in the Australian tropics (including tropical Queensland) is very poor compared to those that also occur in the Brisbane area and are relatively common. Experimental results indicate that when respondents in the sample had an option to allocate $1,000 between ten bird species listed in the survey, it resulted in a greater allocation of funds to the better known and more common species than when they were provided with balanced information about all the selected species. With balanced information the average allocation to bird species confined mostly to the Australian tropics, particularly those threatened or endangered, increased. The general consequences of this for policies for the conservation of birds are discussed.

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Two species of Clinostomum previously described from Australia, C. hornum from Botaurus poiciloptilus (Australian bittern) and Nycticorax caledonicus (Nankeen night heros) and C. australiense from Pelecanus conspicillatus (Australian pelican), which have previously been synonymised with C. complanatum, are redescribed and recognised as valid species. In addition, C. complanatum is recorded from Egretta alba (large egret), E. garzetta (little egret), E. intermedia (plumed egret), N. caledonicus and Ardea novaehollandiae (white-faced heron). C. wilsoni n. sp. is described from E. intermedia from Queensland. C. wilsoni differs from the other three species in size and shape of the body and in the oral collar, oral sucker, intestinal caeca, caecal diverticula and position of testes. Taxonomic problems within the genus Clinostomum are discussed.