| complex communication signals: the case of the blue-black grassquit volatinia jacarina (aves, emberizidae) song. part i--a structural analysis. | the song of the blue-black grassquit volatinia jacarina is different for every individual and the structural differences between individuals are quite complex. samples of songs from different brazilian localities, as well as from venezuela and mexico, were studied through a comparative analysis of their sonograms. from the structural point of view, the results show a song composed of a single note that is compacted in a "window" between 2 and 13 khz and rarely occupying more than half of a secon ... | 2004 | 15258646 |
| reproduction of blue-black grassquits in central brazil. | during the reproductive season blue-black grassquit (volatinia jacarina) males are found in clusters, wherein they exhibit a distinctive display that consists of repeated, vertical leaps while simultaneously producing a brief vocalization. the main objective of this study was to describe details of the species' reproductive behavior in a "cerrado" area of central brazil and compare these data with some studies carried out in other areas. the data obtained concerning different aspects of nesting, ... | 2007 | 17876437 |
| new host records of haemaphysalis leporispalustris (acari: ixodidae) on birds in brazil. | birds are an important component of the life histories and bioecology of a number of tick species and of some tick associated pathogens. an examination of the data concerning bird/tick associations in the neotropics, showed that the tick haemaphysalis leporispalustrisis (packard, 1869) was rarely recorded infesting birds. the current study reports parasitism by h. leporispalustris in wild birds collected from atlantic rain forest environments in the states of rio de janeiro (4ll) and minas gerai ... | 2016 | 26965425 |
| two new and two redescribed species of anonchotaenia (cestoda: paruterinidae) from south american birds. | morphological examination of novel specimens of paruterinid cestodes from passerine birds from brazil and chile and of museum specimens from paraguay revealed two new species: anonchotaenia prolixa sp. n. from elaenia albiceps chilensis hellmayr from chile, and anonchotaenia vaslata sp. n. from tyrannus melancholicus (vieillot) (type host) and myiodynastes maculatus (statius muller) from paraguay. the generic diagnosis of anonchotaenia conn, 1900 is amended, prompted by the presence of the armed ... | 2014 | 25549500 |
| vocal output predicts territory quality in a neotropical songbird. | females who choose highly ornamented mates may gain resources that improve offspring production and survival. studies have focused on the relationship between male quality and the complexity of sexual ornaments; however, less is known of the communicative content of courtship displays, and whether they indicate the quality of resources males can provide to mates. here, we used blue-black grassquits (volatinia jacarina) to test the relationship between male display attributes and territory qualit ... | 2014 | 25043568 |
| immune-related effects from predation risk in neotropical blue-black grassquits (volatinia jacarina). | predation is a major force shaping natural history traits of birds because of their vulnerability during nesting and higher visibility during diurnal activities. for most birds in the neotropics, predation is the major cause of nest failure due to the region's high diversity and abundance of predators. the blue-black grassquit (volatinia jacarina), similarly to other small passerines in the savanna region of central brazil, suffers extremely high rates of nest predation. additionally, males may ... | 2014 | 25038547 |
| the importance of novelty: male-female interactions among blue-black grassquits in captivity. | mate choice is a primary mechanism driving the evolution of sexually selected traits such as elaborate displays and ornaments. in a majority of taxa studied to date, females are seen to actively sample and evaluate multiple males, presumably to optimize mating opportunities. during this process females may encounter males both familiar and novel, a distinction that might influence how mate choice proceeds. using a socially monogamous passerine, the blue-black grassquit (volatinia jacarina), we s ... | 2014 | 24406508 |
| social environment affects acquisition and color of structural nuptial plumage in a sexually dimorphic tropical passerine. | structural colors result from the physical interaction of light with organic materials of differing refractive indexes organized at nanoscale dimensions to produce significant interference effects. because color properties emerge from these finely organized nanostructures, the production of structural coloration could respond to environmental factors and be developmentally more plastic than expected, functioning as an indicator of individual quality. however, there are many unknown factors conce ... | 2012 | 23082172 |
| nanostructural self-assembly of iridescent feather barbules through depletion attraction of melanosomes during keratinization. | avian plumage colours are model traits in understanding the evolution of sexually selected ornamental traits. paradoxically, iridescent structural colours, probably the most dazzling of these traits, remain the most poorly understood. though some data suggest that expression of bright iridescent plumage colours produced by highly ordered arrays of melanosomes and keratin is condition-dependent, almost nothing is known of their ontogeny and thus of any developmental mechanisms that may be suscept ... | 2012 | 21865251 |
| new record of aberrant plumage in blue-black grassquit (volatinia jacarina linnaeus, 1766, aves: emberizidae). | | 2011 | 21755180 |
| social environment affects testosterone level in captive male blue-black grassquits. | the challenge hypothesis proposes that testosterone (t) elevation above what is needed for breeding is associated with social factors, and males possibly modulate their hormonal response to variations in population density and sex ratio. we investigated the role of social environment in altering testosterone levels and aggression in a tropical, seasonally breeding grassquit (volatinia jacarina). we exposed males to three social conditions during 1 year: all-males treatment (six males), mixed tre ... | 2011 | 20950617 |
| iridescent structural colour production in male blue-black grassquit feather barbules: the role of keratin and melanin. | iridescent coloration plays an important role in the visual communication system of many animal taxa. it is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. however, the role of these materials in the production of structural iridescent coloration is still poorly documented. despite the great interspecific variation in the organization of such structures in bird plumage, melanin lay ... | 2009 | 19141431 |
| brazil road-kill: a data set of wildlife terrestrial vertebrate road-kills. | mortality from collision with vehicles is the most visible impact of road traffic on wildlife. mortality due to roads (hereafter road-kill) can affect the dynamic of populations of many species and can, therefore, increase the risk of local decline or extinction. this is especially true in brazil, where plans for road network upgrading and expansion overlaps biodiversity hotspot areas, which are of high importance for global conservation. researchers, conservationists and road planners face the ... | 2018 | 30229895 |
| higher infection probability of haemosporidian parasites in blue-black grassquits (volatinia jacarina) inhabiting native vegetation across brazil. | human induced changes on landscape can alter the biotic and abiotic factors that influence the transmission of vector-borne parasites. to examine how infection rates of vector-transmitted parasites respond to changes on natural landscapes, we captured 330 blue-black grassquits (volatinia jacarina) in brazilian biomes and assessed the prevalence and diversity of avian haemosporidian parasites (plasmodium and haemoproteus) across avian host populations inhabiting environment under different distur ... | 2020 | 33045411 |
| biomonitoring birds: the use of a micronuclei test as a tool to assess environmental pollutants on coffee farms in southeast brazil. | birds have often played an important role as environmental bioindicators, and different species can be useful due to their bioaccumulating capacity. the micronuclei test is a cytologic technique used for accessing dna and is a biomarker for damage to dna. this study analysed the cerrado avian community, especially the efficiency of the blue-black grassquit (volatinia jacarina) in responding to pesticide contamination in situ on different-sized coffee farms in southeast brazil. the micronuclei te ... | 2018 | 29948684 |