Área de vida de Cistothorus platensis (Aves: Troglodytidae) no Cerrado brasileiro

The Sedge Wren Cistothorus platensis (Latham, 1790) is a widely distributed bird species, occurring in natural grasslands through the American continent. Most knowledge on its biology has been obtained in temperate regions, and no information on its home range in tropical grasslands is available. The goal of this study was to examine the home ranges of Sedge Wrens at the Parque Nacional da Chapada dos Veadeiros, central Cerrado, Brazil. Fourteen banded males were studied in a patch of shrubby grassland (campo sujo) between February and December 2008. The mean size of home ranges of five males monitored during the whole period was 6.10 ± 2.09 ha (Minimum Convex Polygon) and 4.57 ± 1.92 ha (Kernel 95%). Home ranges were larger in the dry season (non-breeding period) than in the rainy season (that encompassed both the breeding and non-breeding periods). The overlap between home ranges of neighboring males was small. Sedge Wrens did not establish home ranges on recently burned grasslands. Five banded males were recorded during the entire study period, suggesting the existence of resident individuals. Nine of the 14 males did not persist in the same site throughout the year. There was no evidence of polygyny, as only lone birds or pairs were detected. Our study indicates that Sedge Wrens inhabiting grasslands of the Cerrado are monogamous and have larger home ranges than in temperate regions.(AU)

A corruíra-do-campo Cistothorus platensis (Latham, 1790) apresenta ampla distribuição geográfica, ocorrendo ao longo de todo o continente americano. Informações sobre sua biologia têm sido obtidas principalmente em regiões temperadas, e o conhecimento sobre suas áreas de vida em campos tropicais é inexistente. O objetivo deste trabalho foi estudar as áreas de vida de C. platensis no Parque Nacional da Chapada dos Veadeiros, Cerrado do Brasil central. Quatorze machos foram anilhados em um campo sujo e cinco deles puderam ser acompanhados continuamente entre fevereiro e dezembro de 2008. O tamanho médio das áreas de vida (n = 5) foi de 6,10 ± 2,09 ha (Mínimo Polígono Convexo) e 4,57 ± 1,92 ha (Kernel 95%) e variaram significativamente entre as estações estudadas. As áreas de vida foram maiores na estação seca (período não-reprodutivo) do que na estação chuvosa (que abrangeu os períodos reprodutivo e não-reprodutivo). Houve baixa sobreposição entre áreas de machos vizinhos. As aves estudadas não estabeleceram áreas de vida em trechos de campo recentemente queimados. Alguns indivíduos foram registrados durante todo o período do estudo, sendo assim considerados residentes. Entretanto, nove dos 14 machos não persistiram no local. Não houve evidência de poliginia, uma vez que somente casais ou aves solitárias foram registradas. Este estudo indica que C. platensis habitando campos naturais no Cerrado são monogâmicos e têm áreas de vida maiores do que em regiões temperadas.(AU)

Área de vida de Cistothorus platensis (Aves: Troglodytidae) no Cerrado brasileiro

The Sedge Wren Cistothorus platensis (Latham, 1790) is a widely distributed bird species, occurring in natural grasslands through the American continent. Most knowledge on its biology has been obtained in temperate regions, and no information on its home range in tropical grasslands is available. The goal of this study was to examine the home ranges of Sedge Wrens at the Parque Nacional da Chapada dos Veadeiros, central Cerrado, Brazil. Fourteen banded males were studied in a patch of shrubby grassland (campo sujo) between February and December 2008. The mean size of home ranges of five males monitored during the whole period was 6.10 ± 2.09 ha (Minimum Convex Polygon) and 4.57 ± 1.92 ha (Kernel 95%). Home ranges were larger in the dry season (non-breeding period) than in the rainy season (that encompassed both the breeding and non-breeding periods). The overlap between home ranges of neighboring males was small. Sedge Wrens did not establish home ranges on recently burned grasslands. Five banded males were recorded during the entire study period, suggesting the existence of resident individuals. Nine of the 14 males did not persist in the same site throughout the year. There was no evidence of polygyny, as only lone birds or pairs were detected. Our study indicates that Sedge Wrens inhabiting grasslands of the Cerrado are monogamous and have larger home ranges than in temperate regions.

A corruíra-do-campo Cistothorus platensis (Latham, 1790) apresenta ampla distribuição geográfica, ocorrendo ao longo de todo o continente americano. Informações sobre sua biologia têm sido obtidas principalmente em regiões temperadas, e o conhecimento sobre suas áreas de vida em campos tropicais é inexistente. O objetivo deste trabalho foi estudar as áreas de vida de C. platensis no Parque Nacional da Chapada dos Veadeiros, Cerrado do Brasil central. Quatorze machos foram anilhados em um campo sujo e cinco deles puderam ser acompanhados continuamente entre fevereiro e dezembro de 2008. O tamanho médio das áreas de vida (n = 5) foi de 6,10 ± 2,09 ha (Mínimo Polígono Convexo) e 4,57 ± 1,92 ha (Kernel 95%) e variaram significativamente entre as estações estudadas. As áreas de vida foram maiores na estação seca (período não-reprodutivo) do que na estação chuvosa (que abrangeu os períodos reprodutivo e não-reprodutivo). Houve baixa sobreposição entre áreas de machos vizinhos. As aves estudadas não estabeleceram áreas de vida em trechos de campo recentemente queimados. Alguns indivíduos foram registrados durante todo o período do estudo, sendo assim considerados residentes. Entretanto, nove dos 14 machos não persistiram no local. Não houve evidência de poliginia, uma vez que somente casais ou aves solitárias foram registradas. Este estudo indica que C. platensis habitando campos naturais no Cerrado são monogâmicos e têm áreas de vida maiores do que em regiões temperadas.

Isospora machadoae sp. nov. (Protozoa: Apicomplexa: Eimeriidae), a new coccidian species from white-necked thrushes Turdus albicolis (Passeriformes: Turdidae) of South America

A new coccidian species parasitizing white-necked thrushes Turdus albicollis Vieillot, 1818 is described from the Parque Nacional do Itatiaia, in Southeastern Brazil. Isospora machadoae sp. nov. has oocysts that are sub-spherical, 22.2 × 21.2 µm, with bilayered wall, ~1.3 m thick. Outer layer is rough with micropyle and micropyle cap. Oocyst residuum is absent, but one or two polar granules are present. Sporocysts are ellipsoidal, 13.3 × 9.7 µm. The Stieda body is flattened to half-moon-shaped and substieda body rounded. Sporocyst residuum is present, composed of scattered spherules of different sizes. Sporozoites are vermiform with a refractile body and a nucleus. These parasitized thrushes had no apparent clinical signs of coccidiosis or high densities of oocysts in feces. This condition may be associated with a specific low pathogenicity of I. machadoae sp. nov. and/or with the conserved habitat of these birds, which ensures the ecological niches and thus the immunocompetence to wildlife.

The breeding biology and nest success of the Short-tailed Antthrush Chamaeza campanisona (Aves: Formicariidae) in the Atlantic rainforest of northeastern Brazil

We present the results of a 26-year study on the breeding biology of the Short-tailed Antthrush, Chamaeza campanisona (Lichtenstein, 1823) in an Atlantic rainforest remnant of northeastern Brazil (Alagoas/Pernambuco). We followed the fate of 38 nests, of which 19 failed, 11 succeeded and 8 had an unknown fate. The presence of most nests coincided with the beginning of the rainy season in March/April but nests with eggs and/or chicks were found throughout the year, with no records only in January. Nests were placed inside natural tree cavities that result from broken branches and trunks. Both parents were engaged in feeding the chicks, their diet consisted mainly of insects, spiders, and some unidentified berries. All nests had a clutch size of two eggs. Incubation took 19 days and the mean nestling period was 20.75 days. Mayfield (1975) showed a survival rate of 31.87% and MARK 24.09%. Hotellings T2 revealed no differences in nest characteristics between successful and failed nests (p-value > 0.05). Linear models showed that the size of the entrance of the cavity and its height from ground are the main nest characteristics influencing the nesting success of C. campanisona.

Isospora machadoae sp. nov. (Protozoa: Apicomplexa: Eimeriidae), a new coccidian species from white-necked thrushes Turdus albicolis (Passeriformes: Turdidae) of South America

A new coccidian species parasitizing white-necked thrushes Turdus albicollis Vieillot, 1818 is described from the Parque Nacional do Itatiaia, in Southeastern Brazil. Isospora machadoae sp. nov. has oocysts that are sub-spherical, 22.2 × 21.2 µm, with bilayered wall, ~1.3 m thick. Outer layer is rough with micropyle and micropyle cap. Oocyst residuum is absent, but one or two polar granules are present. Sporocysts are ellipsoidal, 13.3 × 9.7 µm. The Stieda body is flattened to half-moon-shaped and substieda body rounded. Sporocyst residuum is present, composed of scattered spherules of different sizes. Sporozoites are vermiform with a refractile body and a nucleus. These parasitized thrushes had no apparent clinical signs of coccidiosis or high densities of oocysts in feces. This condition may be associated with a specific low pathogenicity of I. machadoae sp. nov. and/or with the conserved habitat of these birds, which ensures the ecological niches and thus the immunocompetence to wildlife.(AU)

The breeding biology and nest success of the Short-tailed Antthrush Chamaeza campanisona (Aves: Formicariidae) in the Atlantic rainforest of northeastern Brazil

We present the results of a 26-year study on the breeding biology of the Short-tailed Antthrush, Chamaeza campanisona (Lichtenstein, 1823) in an Atlantic rainforest remnant of northeastern Brazil (Alagoas/Pernambuco). We followed the fate of 38 nests, of which 19 failed, 11 succeeded and 8 had an unknown fate. The presence of most nests coincided with the beginning of the rainy season in March/April but nests with eggs and/or chicks were found throughout the year, with no records only in January. Nests were placed inside natural tree cavities that result from broken branches and trunks. Both parents were engaged in feeding the chicks, their diet consisted mainly of insects, spiders, and some unidentified berries. All nests had a clutch size of two eggs. Incubation took 19 days and the mean nestling period was 20.75 days. Mayfield (1975) showed a survival rate of 31.87% and MARK 24.09%. Hotellings T2 revealed no differences in nest characteristics between successful and failed nests (p-value > 0.05). Linear models showed that the size of the entrance of the cavity and its height from ground are the main nest characteristics influencing the nesting success of C. campanisona.(AU)

Reproductive aspects of the Purple-throated Euphonia, Euphonia chlorotica (Aves: Fringillidae) in southeastern Brazil, and first record of the species nesting inside a vespiary

Despite the fact that E. chlorotica (Linnaeus, 1766) is common and widely distributed in South America, the reproductive aspects of the species are poorly documented. Here we present data on 18 active nests found from August to February, between 2007 and 2012. Nests were globular with a lateral entrance, and measured 97.9 ± 14.4 mm in outside height, 110.6 ± 11.6 mm in outside diameter, and were 4.88 ± 2.09 m above ground. They were often supported from bellow and were composed mainly of tiny dry leafs and leaflets, fine petioles, and plumed seeds, all compacted with spider web silk. Eggs were laid on consecutive days or with one day interval, and clutch size varied from 1-3 eggs (2.1 ± 0.6, n = 9 nests). Only females incubated the eggs, but both sexes were involved in nest construction and nestling attendance at similar rates. Incubation and nestling periods were 14 and 21 days, respectively, and overall nest survival probability was 5%. A vespiary used for nesting was not occupied by wasps and nest material was deposited only to form the incubatory chamber. Although nesting near wasps or bees is a widespread strategy among birds in general, nesting inside the nests of social insects is a poorly documented behavior.

Reproductive aspects of the Purple-throated Euphonia, Euphonia chlorotica (Aves: Fringillidae) in southeastern Brazil, and first record of the species nesting inside a vespiary

Despite the fact that E. chlorotica (Linnaeus, 1766) is common and widely distributed in South America, the reproductive aspects of the species are poorly documented. Here we present data on 18 active nests found from August to February, between 2007 and 2012. Nests were globular with a lateral entrance, and measured 97.9 ± 14.4 mm in outside height, 110.6 ± 11.6 mm in outside diameter, and were 4.88 ± 2.09 m above ground. They were often supported from bellow and were composed mainly of tiny dry leafs and leaflets, fine petioles, and plumed seeds, all compacted with spider web silk. Eggs were laid on consecutive days or with one day interval, and clutch size varied from 1-3 eggs (2.1 ± 0.6, n = 9 nests). Only females incubated the eggs, but both sexes were involved in nest construction and nestling attendance at similar rates. Incubation and nestling periods were 14 and 21 days, respectively, and overall nest survival probability was 5%. A vespiary used for nesting was not occupied by wasps and nest material was deposited only to form the incubatory chamber. Although nesting near wasps or bees is a widespread strategy among birds in general, nesting inside the nests of social insects is a poorly documented behavior.(AU)

Histopathological Diagnosis Of Eyelid Tumor In Moustached Wren (Pheugopedius Genibarbis Swainson, 1838) (Passeriforme, Troglodytidae). A Case Report

The aim of this work was to describe an eyelid neoplasm in wild birds, since the veterinary literature has little information concerning the aspects of the oncologic clinic in wild species. In the clinical exam, it was observed a single mass in the upper right eyelid of the Pheugopedius genibarbis a, with rough surface, cauliflower aspect, of dark-red coloration . For the histopathological diagnosis, an incisional biopsy of the lesion was done , with the fragment fixed in 10% buffered neutral formalin, processed by the method of inclusion in paraffin , cut to 4µm sections and stained with H&E . The histopathological findings revealed elongated dermal papillae covered by acanthotic epidermis, as well as thickness of the stratum spinosum . In the stratum spinosum, it was observed the presence of cells with vacuolated cytoplasm and nucleus slightly dislocated to the center of the cell, which increases in proportion when closer to the granular layer, an indication of hydropic degeneration , there were In the basal layer it is possible to notice the presence of the normal mitotic figures.. Based on the macro and microscopic characteristics, that neoplasm was diagnosed as an eyelid papilloma.

Extraintestinal isosporoid coccidian causing atoxoplasmosis in captive green-winged saltators: clinical and hematological features / Coccidiose extraintestinal causando atoxoplasmose em trinca-ferros de cativeiro: aspectos clínicos e hematológicos

Populations of green-winged saltators, Saltator similis, are decreasing especially because of illegal trade and infectious diseases. We describe natural cases of an extraintestinal isosporoid coccidian in caged S. similis, and suggest the need of preventive measures in handling these birds. Nonspecific clinical signs were seen in all of them, however, intracytoplasmic Atoxoplasma sp. was found in peripheral blood, reinforcing the idea of systemic isosporosis. Leukocytosis with high number of heterophils and monocytes suggested that atoxoplasmosis in green-winged saltators can progress as an acute disease. The birds showed clinical improvement after treatment. Handling recommendations were proposed to upgrade hygienic conditions of the facilities. We concluded that nonspecific symptoms and an acute inflammatory process can be associated with atoxoplasmosis in young S. similis. We emphasize the importance of blood smear to detect merozoites.(AU)

As populações de trinca-ferro, Saltator similis, estão declinando especialmente em função do comércio illegal e das doenças infecciosas. Descrevem-se casos naturais de coccidiose extraintestinal em S. similis de cativeiro, sugerindo a necessidade de medidas preventivas no manejo desses animais. Sinais clínicos inespecíficos foram observados em todos os animais, contudo, formas intracitoplasmáticas de Atoxoplasma sp. foram vistas no sangue periférico, reforçando a ideia de isosporose sistêmica. Leucocitose com aumento de heterófilos e monócitos sugeriram que a atoxoplasmose em trinca-ferro pode progredir como uma doença aguda. As aves apresentaram melhora clínica após tratamento. Recomendações de manejo foram propostas a fim de melhorar as condições higiênicas das instalações das aves. Concluiu-se que sinais inespecíficos e processo inflamatório agudo podem ser associados com a atoxoplasmose em S. similis jovens. Enfatizamos a importância da avaliação do esfregaço sanguíneo para detector os merozoítos.(AU)

Histopathological Diagnosis Of Eyelid Tumor In Moustached Wren (Pheugopedius Genibarbis Swainson, 1838) (Passeriforme, Troglodytidae). A Case Report

The aim of this work was to describe an eyelid neoplasm in wild birds, since the veterinary literature has little information concerning the aspects of the oncologic clinic in wild species. In the clinical exam, it was observed a single mass in the upper right eyelid of the Pheugopedius genibarbis a, with rough surface, cauliflower aspect, of dark-red coloration . For the histopathological diagnosis, an incisional biopsy of the lesion was done , with the fragment fixed in 10% buffered neutral formalin, processed by the method of inclusion in paraffin , cut to 4µm sections and stained with H&E . The histopathological findings revealed elongated dermal papillae covered by acanthotic epidermis, as well as thickness of the stratum spinosum . In the stratum spinosum, it was observed the presence of cells with vacuolated cytoplasm and nucleus slightly dislocated to the center of the cell, which increases in proportion when closer to the granular layer, an indication of hydropic degeneration , there were In the basal layer it is possible to notice the presence of the normal mitotic figures.. Based on the macro and microscopic characteristics, that neoplasm was diagnosed as an eyelid papilloma.(AU)

Extraintestinal isosporoid coccidian causing atoxoplasmosis in captive green-winged saltators: clinical and hematological features / Coccidiose extraintestinal causando atoxoplasmose em trinca-ferros de cativeiro: aspectos clínicos e hematológicos

Populations of green-winged saltators, Saltator similis, are decreasing especially because of illegal trade and infectious diseases. We describe natural cases of an extraintestinal isosporoid coccidian in caged S. similis, and suggest the need of preventive measures in handling these birds. Nonspecific clinical signs were seen in all of them, however, intracytoplasmic Atoxoplasma sp. was found in peripheral blood, reinforcing the idea of systemic isosporosis. Leukocytosis with high number of heterophils and monocytes suggested that atoxoplasmosis in green-winged saltators can progress as an acute disease. The birds showed clinical improvement after treatment. Handling recommendations were proposed to upgrade hygienic conditions of the facilities. We concluded that nonspecific symptoms and an acute inflammatory process can be associated with atoxoplasmosis in young S. similis. We emphasize the importance of blood smear to detect merozoites.(AU)

As populações de trinca-ferro, Saltator similis, estão declinando especialmente em função do comércio illegal e das doenças infecciosas. Descrevem-se casos naturais de coccidiose extraintestinal em S. similis de cativeiro, sugerindo a necessidade de medidas preventivas no manejo desses animais. Sinais clínicos inespecíficos foram observados em todos os animais, contudo, formas intracitoplasmáticas de Atoxoplasma sp. foram vistas no sangue periférico, reforçando a ideia de isosporose sistêmica. Leucocitose com aumento de heterófilos e monócitos sugeriram que a atoxoplasmose em trinca-ferro pode progredir como uma doença aguda. As aves apresentaram melhora clínica após tratamento. Recomendações de manejo foram propostas a fim de melhorar as condições higiênicas das instalações das aves. Concluiu-se que sinais inespecíficos e processo inflamatório agudo podem ser associados com a atoxoplasmose em S. similis jovens. Enfatizamos a importância da avaliação do esfregaço sanguíneo para detector os merozoítos.(AU)

Extra-pair paternity in a Neotropical rainforest songbird, the White-necked Thrush Turdus albicollis (Aves: Turdidae)

Over the last two decades, several studies have shown that the mating systems of various birds are more complex than previously believed, and paternity tests performed with molecular techniques have proved, for instance, that the commonly observed social monogamy often presents important variations, such as extra-pair paternity. However, data are still largely biased towards temperate species. In our study, at an area of the Brazilian Atlantic Forest, we found broods containing at least one extra-pair young (EPY) in the socially monogamous White-necked Thrush Turdus albicollis (Vieillot, 1818). Paternity tests using six heterologous microsatellite loci revealed that four of 11 broods (36.4%) presented at least one extra-pair young (EPY). This rate of EPY is within the range found for other studies in the tropics. This is one of the few studies that present detailed paternity analyses of a Neotropical rainforest passerine. Our findings corroborate the early insights that breeding strategies involving cheating can also be widespread among Neotropical socially monogamous songbirds.

Extra-pair paternity in a Neotropical rainforest songbird, the White-necked Thrush Turdus albicollis (Aves: Turdidae)

Over the last two decades, several studies have shown that the mating systems of various birds are more complex than previously believed, and paternity tests performed with molecular techniques have proved, for instance, that the commonly observed social monogamy often presents important variations, such as extra-pair paternity. However, data are still largely biased towards temperate species. In our study, at an area of the Brazilian Atlantic Forest, we found broods containing at least one extra-pair young (EPY) in the socially monogamous White-necked Thrush Turdus albicollis (Vieillot, 1818). Paternity tests using six heterologous microsatellite loci revealed that four of 11 broods (36.4%) presented at least one extra-pair young (EPY). This rate of EPY is within the range found for other studies in the tropics. This is one of the few studies that present detailed paternity analyses of a Neotropical rainforest passerine. Our findings corroborate the early insights that breeding strategies involving cheating can also be widespread among Neotropical socially monogamous songbirds.(AU)

Hemangiosarcoma in a free-living Rufous-bellied Thrush (Turdus rufiventris)

Background: Hemangiosarcoma is a malignant endothelial cell-derived neoplasm characterized by an intense cellular proliferation organized in a solid or cavernous pattern. Is characterized by intense cell proliferation, and organized in vascular slits, filled with blood, with fast grow and there is a high recurrence rate. This paper reports a case of multiple hemangiosarcoma in a Rufous-bellied Thrush (Turdus rufiventris). Case: A free-living Rufous-bellied Thrush (Turdus rufiventris), was attended at the veterinary hospital of the Federal University of Mato Grosso (UFMT) - Cuiabá, presenting prostration and three masses located in the following regions: left periorbital area, left lateral insertion of the beak and distal portion of the left tibia. The masses were blackened colored with an irregular aspect, and the cut surface was multiple cavity, filled with a blackened gelatinous material. The animal died during the surgical procedure and was sent to necropsy. Additionally, special immunohistochemistry staining was used in the tumors sections, with primary anti-S-100, anti-Von Willebrand Factor, anti-desmin, anti-actin, anti-cytokeratin and anti-vimentin. The three masses have rounded shape, multilobuled surface, deep red to blackened color, with skin adhered base, and, when cut, blackened color with multiple cavities filled with red to blackened gelatinous material and [...]

Hemangiosarcoma in a free-living Rufous-bellied Thrush (Turdus rufiventris)

Background: Hemangiosarcoma is a malignant endothelial cell-derived neoplasm characterized by an intense cellular proliferation organized in a solid or cavernous pattern. Is characterized by intense cell proliferation, and organized in vascular slits, filled with blood, with fast grow and there is a high recurrence rate. This paper reports a case of multiple hemangiosarcoma in a Rufous-bellied Thrush (Turdus rufiventris). Case: A free-living Rufous-bellied Thrush (Turdus rufiventris), was attended at the veterinary hospital of the Federal University of Mato Grosso (UFMT) - Cuiabá, presenting prostration and three masses located in the following regions: left periorbital area, left lateral insertion of the beak and distal portion of the left tibia. The masses were blackened colored with an irregular aspect, and the cut surface was multiple cavity, filled with a blackened gelatinous material. The animal died during the surgical procedure and was sent to necropsy. Additionally, special immunohistochemistry staining was used in the tumors sections, with primary anti-S-100, anti-Von Willebrand Factor, anti-desmin, anti-actin, anti-cytokeratin and anti-vimentin. The three masses have rounded shape, multilobuled surface, deep red to blackened color, with skin adhered base, and, when cut, blackened color with multiple cavities filled with red to blackened gelatinous material and [...](AU)

Feeding resource partitioning between two understorey insectivorous birds in a fragment of Neotropical cloud forest / Partição de recursos alimentares entre duas espécies de aves insetívoras de sub-bosque em um fragmento de floresta nebular Neotropical

The food habits and niche overlap based on diet composition and prey size of two species of understorey insectivorous birds were investigated in an area of montane rain forest in the state of Minas Gerais, southeastern Brazil. A total of 43 birds were captured: 33 individuals of Conopophaga lineata (Conopophagidae) with 13 recaptures, and 10 individuals of Myiothlypis leucoblephara (Parulidae) with 12 recaptures, from which were obtained respectively 33 and 10 fecal samples. Fragments of 16 groups of arthropods, plus insect eggs, were identified in these samples. Conopophaga lineata predominantly consumed Formicidae (32%) and Isoptera (23.6%). However, the index of alimentary importance (AI) of Isoptera (3.53) was lower than other groups such as Formicidae (AI = 61.88), Coleoptera (AI = 16.17), insect larvae (AI = 6.95) and Araneae (AI = 6.6). Myiothlypis leucoblephara predominantly consumed Formicidae (28.2%) and Coleoptera (24.4%), although Coleoptera and Hymenoptera non-Formicidae had the highest values of AI (38.71 and 22.98 respectively). Differences in the proportions of the types of arthropods consumed by birds were not enough to reveal their separation into feeding niches (overlap = 0.618, p observed ≤ expected = 0.934), whereas differences in the use of resources was mainly due to the size of the prey (p<0.001), where C lineata, the species with the highest body mass (p<0.001) consumed larger prey. It is plausible that prey size is an axis of niche dimension that allows the coexistence of these species.(AU)

Os hábitos alimentares e a sobreposição de nicho em termos de composição da dieta e tamanho de presas de duas espécies de aves insetívoras de sub-bosque foram investigados em uma área de floresta ombrófila altomontana no estado de Minas Gerais, sudeste do Brasil. Foram capturados 33 indivíduos de Conopophaga lineata (Conopophagidae), com 13 recapturas, e 10 indivíduos de Myiothlypis leucoblephara (Parulidae), com 12 recapturas, dos quais foram obtidas, respectivamente, 33 e 10 amostras fecais, onde foram identificados fragmentos de 16 grupos de artrópodes, além de ovos de insetos. Conopophaga lineata consumiu predominantemente Formicidae (32%) e Isoptera (23,6%). Contudo, o índice de importância alimentar (IA) de Isoptera (3,53) esteve abaixo de outros grupos como Formicidae (IA = 61,88), Coleoptera (IA = 16,17), larva de inseto (IA = 6,95) e Araneae (IA = 6,6). Myiothlypis leucoblephara consumiu predominantemente Formicidae (28,2%) e Coleoptera (24,4%), embora em termos de IA o predomínio tenha sido de Coleoptera (IA = 38,71) e Hymenoptera não Formicidae (IA = 22,98). Diferenças nas proporções dos tipos de artrópodes consumidos pelas aves não foram suficientes para revelar separação em seus nichos alimentares (sobreposição = 0,618; p observado ≤ esperado = 0,934), ao passo que divergências no uso de recursos se deram principalmente em função dos tamanhos das presas (p<0,001), onde C. lineata, a espécie com maior massa corporal, (p<0,001) consumiu as maiores presas. É plausível que o tamanho das presas seja um eixo da dimensão do nicho que permite a coexistência dessas espécies.(AU)

Jaw musculature of Cyclarhis gujanensis (Aves: Vireonidae) / Musculatura das maxilas de Cyclarhis gujanensis(Aves: Vireonidae)

Cyclarhis gujanensis is a little bird which feeds on high number of large preys, such frogs, lizards, snakes, bats and birds. As there are few studies on the cranial anatomy of this species, we aimed to describe the cranial myology to contribute to the anatomical knowledge of this species and to make some assumptions about functional anatomy. Thus, we described the muscles from the jaw apparatus (external and internal adductor muscles, the muscles of the pterygoid system and the depressor muscles of the mandible). The adductor system is the greatest and multipinulated, particularly in its origin in the caudal portion of the temporal fossa. The depressor jaw muscles systems are enlarged with many components in complexity. The most of jaw apparatus muscles are short, but the strength (biting or crushing forces) from short feeding apparatus fibers probably is increased by high number of components and pinnulation. These anatomical aspects of the muscles indicate a considerable force in the jaws, without which C. gujanensis probably could not cut their prey into smaller pieces. However, functional approaches to analysis of forces of the muscle fibers are needed to corroborate / refute the hypotheses mentioned above.(AU)

O pitiguari (C. gujanensis) é um pássaro neotropical que se alimenta de uma ampla variedade de presas grandes, tais como lagartos, anuros, morcegos e aves. Como são escassos os estudos sobre a anatomia craniana desta espécie, descrevemos a miologia craniana para contribuir com o seu conhecimento anatômico e inferir hipóteses sobre sua anatomia funcional. Foram descritos os músculos adutores mandibulares, externos e internos, do sistema pterigóideo e depressores da mandíbula. O sistema adutor, com a função de elevar a mandíbula, é o mais desenvolvido, particularmente em sua origem na porção caudal da fossa temporal. O músculo depressor da mandíbula possui vários componentes. A maioria dos músculos do aparato mandibular tem tamanho pequeno, porém a ave possui um grande potencial para dilacerar, e essa força provavelmente se deve ao grande número de componentes e pinulações neles presentes. Esses aspectos anatômicos da musculatura indicam uma força considerável nas maxilas, sem a qual C. gujanensis provavelmente não conseguiria cortar suas presas em pedaços menores. No entanto, mais estudos, tanto em abordagens funcionais como análises de forças das fibras musculares, são necessários para corroborar/refutar as hipóteses mencionadas acima.(AU)

Comunidade e partilha ecológica de turdídeos (aves: passeriformes) em um fragmento urbano de floresta com araucárias em Guarapuava no sul do Brasil / Community and ecological partitioning of turdid (passerines) in an araucaria urban forest fragment in Guarapuava, southern Brazil / Comunidad y reparto ecológico de turdidae (aves paseriformes) en un espacio urbano de bosque con araucarias en Guarapuava en el sur de Brasil

Mecanismos ecológicos que permitem a coexistência de sabiás do gênero Turdus (Turdidae) parecem não ser tão facilmente explicáveis. Neste sentido, o presente trabalho buscou compreender como está estruturada a comunidade dessas aves e investigar possíveis padrões e mecanismos que tornam possível a coexistência entre duas espécies aparentadas e relativamente semelhantes, T. leucomelas e T. rufiventris, que compartilham um fragmento florestal urbano. Por meio de capturas utilizando redes ornitológicas, foi possível descrever a estrutura da comunidade, obtendo dados ecológicos e morfológicos de cinco espécies do gênero. Para a análise da coexistência entre T. leucomelas e T. rufiventris, os parâmetros amostrados foram a abundância média por ambiente amostrado em relação às estações, estrato florestal utilizado pelas aves, aspectos morfológicos e a dieta. Os resultados apontaram que Turdus rufiventris é o mais abundante dos sabiás ocorrentes na área e também o mais constante ao longo do estudo, estando presente em 66% dos eventos de captura. Turdus leucomelas aparece em segundo lugar nas capturas com frequência de ocorrência de 55%. Turdus amaurochalinus, com 84% de ocorrência na primavera (57% anual), pode apresentar sobreposição de populações migrantes sobre populações residentes durante a mesma estação. Por sua vez, Turdus albicollis foi considerada acessória com frequência máxima de 30% no inverno. Quanto a sua dominância, Turdus subalaris foi considerada recessiva e ocasional em sua constância nas capturas. Comparações efetuadas entre T. leucomelas e T. rufiventris demonstram grande semelhança de massa corpórea, enquanto em outras variáveis, como comprimento, houve diferença significativa. Entretanto, T. rufiventris apresenta maiores amplitudes de variação e bico mais fino e comprido. (AU)

Ecological mechanisms that allow the coexistence of five Thrush species from the Turdus (Turdidae) genus in an urban forest fragment in southern Brazil seem to be difficult to explain. In this context, the present paper tried to understand how the bird community is structured, as well as to investigate possible patterns and mechanisms that make the coexistence of two related and relatively similar species - T. leucomelas and T. rufiventris possible. Mist nets were used for sampling, which allowed the description of the community structure with ecological and morphological data on five species of the genus. For the coexistence analysis between T. leucomelas and T. rufiventris, the parameters surveyed were the average abundance per sampled environment in relation to seasons, forest stratum used by birds, morphological aspects, and diet. Results indicated that Turdus rufiventris is the most abundant thrush in the area and is the most constantly found throughout this study, present in 66% of captures. Turdus leucomelas occurred in 55% of captures. Turdus amaurochalinus, with 84% occurrence in spring (57% yearly), may present an overlapping of migrant populations over resident ones in the same season. Turdus albicollis was considered supplementary, with maximum frequency of 30% in winter. As for its dominance, Turdus subalaris was regarded as recessive and occasional in its constancy in captures. Comparisons made between T. leucomelas and T. rufiventris showed great resemblance of body mass, while in other variables, such as length, there were significant differences. However, T. rufiventris presents higher degrees of variation, as well as thinner and longer beaks.(AU)

Mecanismos ecológicos que permiten la coexistencia de aves del género Turdus (Turdidae), parecen no ser tan fácilmente explicables. Este estudio ha buscado comprender como está estructurada la comunidad de esas aves e investigar posibles estándares y mecanismos que hacen posible la coexistencia entre dos especies aparentadas y relativamente semejantes, T. leucomelas y T. rufiventris, que comparten un espacio de bosque urbano. A través de capturas utilizando redes ornitoló- gicas, ha sido posible describir la estructura de la comunidad, obteniendo datos ecológicos y morfológicos de cinco especies del género. Para el análisis de la coexistencia entre T. leucomelas y T. rufiventris, los parámetros muestreados fueron la abundancia promedia por ambiente estudiado en relación a las estaciones, estrato del bosque utilizado por las aves, aspectos morfológicos y la dieta. Los resultados apuntaron que Turdus rufiventris es el más abundante de los zorzales ocurrentes en el área y también el más constante a lo largo del estudio, estando presente en 66% de los eventos de captura. Turdus leucomelas aparece en segundo lugar en las capturas con frecuencia de ocurrencia de 55%. Turdus amaurochalinus, con 84% de ocurrencia en la primavera (57% anual), puede presentar superposición de poblaciones migrantes sobre poblaciones residentes durante la misma estación. Por su vez, Turdus albicollis ha sido considerada accesoria con frecuencia máxima de 30% en el invierno. Cuanto a su dominancia, Turdus subalaris ha sido considerada recesiva y ocasional en su constancia en las capturas. Comparaciones efectuadas entre T. leucomelas y T. rufiventris demuestran gran semejanza de masa corpórea, mientras en otras variables, como de largo, hubo diferencia significativa. Entretanto, T. rufiventris presenta mayores amplitudes de variación y pico delgado y largo.(AU)