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The Rufous treepie (Dendrocitta vagabunda) belongs to family corvidae, order Passeriformes which includes about 100 species. The current study was conducted to gather information about the Population distribution and habitat analysis of D. vagabunda at District Abbottabad, Pakistan. The data were collected on monthly basis both morning and evening times (2018-2019). The "Point count Method" was used for population estimation and "Quadrates Method" for habitat analysis of study area. The result shows an average month-wise population density of D. vagabunda was maximum at Jhangra 0.14±0.039/ha, whereas minimum at Havelian 0.11±0.022/ha. There was no significant difference (p>0.05) among monthly population densities of D. vagabunda, however, a significant difference (p<0.05) was found between morning and evening times population of the specie. The present study revealed that importance value index (IVI) of plants species at Sherwan, Bakot, Havelian, Langra and Jhangra were 59.6±12.6, 50.1±6.9, 53.4±6.3, 66.8±10 and 60.1±7.7. Likewise, the frequency of shrubs at Sherwan, Bakot, Havelian, Langra and Jhangra were 33.3±4.2, 45±9.4, 46.7±8.2, 55.6±22.2 and 37.5±8.5. Similarly, the frequency of herbs at Sherwan, Bakot, Havelian, Langra and Jhangra were 40.4±6.0, 37.5±5.6, 53.3±7.4, 48.5±5.2 and 46.9±7.4 respectively. Our results show the study area as suitable habitat for D. vagabunda.(AU)

A trepadeira Rufous (Dendrocitta vagabunda) pertence à família corvidae, ordem Passeriformes que inclui cerca de 100 espécies. O estudo atual foi realizado para reunir informações sobre a distribuição da população e análise do habitat de D. vagabunda no distrito de Abbottabad, Paquistão. Os dados foram coletados mensalmente pela manhã e à noite (2018-2019). O "método de contagem de pontos" foi usado para estimativa da população e o "método dos quadrados" para análise de habitat da área de estudo. O resultado mostra que uma densidade populacional média mensal de D. vagabunda foi máxima em Jhangra 0,14 ± 0,039 / ha, enquanto a mínima em Havelian 0,11 ± 0,022/ha. Não houve diferença significativa (p> 0,05) entre as densidades populacionais mensais de D. vagabunda, entretanto foi encontrada diferença significativa (p <0,05) entre os períodos matutino e noturno da população da espécie. O presente estudo revelou que o índice de valor de importância (IVI) das espécies de plantas em Sherwan, Bakot, Havelian, Langra e Jhangra foi de: 59,6 ± 12,6, 50,1 ± 6,9, 53,4 ± 6,3, 66,8 ± 10 e 60,1 ± 7,7. Da mesma forma, a frequência de arbustos em Sherwan, Bakot, Havelian, Langra e Jhangra foi de: 33,3 ± 4,2, 45 ± 9,4, 46,7 ± 8,2, 55,6 ± 22,2 e 37,5 ± 8,5. Da mesma forma, a frequência de ervas em Sherwan, Bakot, Havelian, Langra e Jhangra foi: 40,4 ± 6,0, 37,5 ± 5,6, 53,3 ± 7,4, 48,5 ± 5,2 e 46,9 ± 7,4, respectivamente. Nossos resultados mostram a área de estudo como habitat adequado para D. vagabunda.(AU)

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The Rufous treepie (Dendrocitta vagabunda) belongs to family corvidae, order Passeriformes which includes about 100 species. The current study was conducted to gather information about the Population distribution and habitat analysis of D. vagabunda at District Abbottabad, Pakistan. The data were collected on monthly basis both morning and evening times (2018-2019). The "Point count Method" was used for population estimation and "Quadrates Method" for habitat analysis of study area. The result shows an average month-wise population density of D. vagabunda was maximum at Jhangra 0.14±0.039/ha, whereas minimum at Havelian 0.11±0.022/ha. There was no significant difference (p>0.05) among monthly population densities of D. vagabunda, however, a significant difference (p<0.05) was found between morning and evening times population of the specie. The present study revealed that importance value index (IVI) of plants species at Sherwan, Bakot, Havelian, Langra and Jhangra were 59.6±12.6, 50.1±6.9, 53.4±6.3, 66.8±10 and 60.1±7.7. Likewise, the frequency of shrubs at Sherwan, Bakot, Havelian, Langra and Jhangra were 33.3±4.2, 45±9.4, 46.7±8.2, 55.6±22.2 and 37.5±8.5. Similarly, the frequency of herbs at Sherwan, Bakot, Havelian, Langra and Jhangra were 40.4±6.0, 37.5±5.6, 53.3±7.4, 48.5±5.2 and 46.9±7.4 respectively. Our results show the study area as suitable habitat for D. vagabunda.

A trepadeira Rufous (Dendrocitta vagabunda) pertence à família corvidae, ordem Passeriformes que inclui cerca de 100 espécies. O estudo atual foi realizado para reunir informações sobre a distribuição da população e análise do habitat de D. vagabunda no distrito de Abbottabad, Paquistão. Os dados foram coletados mensalmente pela manhã e à noite (2018-2019). O "método de contagem de pontos" foi usado para estimativa da população e o "método dos quadrados" para análise de habitat da área de estudo. O resultado mostra que uma densidade populacional média mensal de D. vagabunda foi máxima em Jhangra 0,14 ± 0,039 / ha, enquanto a mínima em Havelian 0,11 ± 0,022/ha. Não houve diferença significativa (p> 0,05) entre as densidades populacionais mensais de D. vagabunda, entretanto foi encontrada diferença significativa (p <0,05) entre os períodos matutino e noturno da população da espécie. O presente estudo revelou que o índice de valor de importância (IVI) das espécies de plantas em Sherwan, Bakot, Havelian, Langra e Jhangra foi de: 59,6 ± 12,6, 50,1 ± 6,9, 53,4 ± 6,3, 66,8 ± 10 e 60,1 ± 7,7. Da mesma forma, a frequência de arbustos em Sherwan, Bakot, Havelian, Langra e Jhangra foi de: 33,3 ± 4,2, 45 ± 9,4, 46,7 ± 8,2, 55,6 ± 22,2 e 37,5 ± 8,5. Da mesma forma, a frequência de ervas em Sherwan, Bakot, Havelian, Langra e Jhangra foi: 40,4 ± 6,0, 37,5 ± 5,6, 53,3 ± 7,4, 48,5 ± 5,2 e 46,9 ± 7,4, respectivamente. Nossos resultados mostram a área de estudo como habitat adequado para D. vagabunda.

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Culicivora caudacuta occurs in the Cerrado, Pampa and Chaco grasslands of Bolivia, Brazil, Paraguay, Argentina and Uruguay. Its breeding biology is poorly known. Here, I present a summary of the published information and new data gathered between 2003 and 2009 in southeast Brazil at Tapira, Minas Gerais. Breeding occurred during the rainy season (October to March), clutch size being three eggs. Juveniles and immatures show a different plumage from the adults, mostly brownish orange. All nests studied at Tapira showed evidence of cooperative breeding, with one helper engaged in incubation and provisioning the young. This is the first observations of this behavior for the species. The species has a wider range than currently understood and its presence in protected areas is similarly more common.(AU)

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Introduction: Body size is an essential trait for endotherms to face the physiological requirements of cold, so there is a tendency to large body size at high altitudes and latitudes, known as Bergmann's rule. However, the validity of this ecomorphological rule to small-bodied endotherms across altitudinal gradients is poorly known. Objective: To understand the effects of environmental variation on body size, we assessed whether interspecific variation in body size of small tropical endotherms follows Bergmann's rule along tropical altitudinal gradients. Methods: We compiled data on elevational ranges and body masses for 133 species of hummingbirds of Colombia. We then assessed the association between body mass and mid-point of the altitudinal distribution using phylogenetic generalized least squares (PGLS) analyses under different evolutionary models. Results: We found a decelerating rate of evolution for body size since the Early Burst model of evolution provided a better fit to body mass data. For elevational range, we found a slow and constant rate since Pagel's lambda model provided a better fit to the mid-point of the altitudinal distribution data. Besides, phylogenetic regression analysis indicated that body mass and the altitudinal range of hummingbirds are associated through the phylogeny, with a positive but slight association (R2= 0.036). Conclusions: We found that body mass and altitude of hummingbirds are positively related, which is in agreement with expectations under Bergmann's rule. However, this association was weaker than expected for small and non-passerine birds like hummingbirds. Thus, our results suggest that environmental changes across altitudinal gradients do not strongly influence body mass in small tropical endotherms as hummingbirds.

Introducción: El tamaño corporal es un rasgo importante para determinar la respuesta de los endotermos a los requerimientos que exigen las zonas frías, por lo cual se espera una tendencia hacia el incremento del tamaño corporal al aumentar la altitud y la latitud. Sin embargo, se conoce poco acerca de la validez de esta regla ecomorfológica, conocida como la regla de Bergmann, para endotermos pequeños en gradientes altitudinales tropicales. Objetivo: Con el fin de entender los efectos de la variación ambiental sobre el tamaño corporal, se evaluó sí la variación interespecífica en la masa corporal de endotermos tropicales pequeños se ajusta a la regla de Bergmann a lo largo de gradientes de elevación. Métodos: Se compilaron datos sobre los rangos de distribución altitudinal y los tamaños corporales de 133 especies de colibríes en Colombia. Posteriormente, se evaluó la asociación entre la masa corporal y el punto medio de distribución altitudinal de los colibríes mediante análisis de mínimos cuadrados generalizados filogenéticos (PGLS) bajo diferentes modelos evolutivos. Resultados: La evolución de la masa corporal se ajustó mejor a un modelo de evolución Early Burst, mientras que el rango de elevación al modelo evolutivo lambda de Pagel; lo que indica que la tasa de evolución es desacelerada para el tamaño del cuerpo, mientras es lenta y constante para el rango de elevación. Además, el análisis de regresión filogenética indica que la masa corporal y el rango de elevación están positiva y ligeramente asociados (R2 = 0.036). Conclusiones: De acuerdo con lo esperado por la regla de Bergmann, los resultados indican que los colibríes tienden a ser más grandes a mayores altitudes. Sin embargo, esta asociación es más débil de lo esperado para aves no paseriformes de tamaño pequeño como los colibríes.Por lo tanto, los resultados sugieren que las variaciones ambientales a lo largo de gradientes de elevación no tienen una influencia fuerte sobre el tamaño corporal de endotermos pequeños como los colibríes.

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In this study, the bones forming the poultry skeleton of the Dalmatian pelican were macroscopically examined. For this purpose, three Dalmatian pelicans were used. In the Dalmatian pelicans, the shoulder girdle (Ossa cinguli membri thoracici) is formed by the scapula, os coracoideum and clavicula bones. The scapula bone was short and flat. The humerus was a long bone with a cylindrical, pneumatic structure. Os corocoideum was also in the processus coracoideus tuber. Radius formed a joint with the ulna, and presented a slight slope from proximal to distal direction. Ossa carpi bones (skeleton manus) were composed of os carpi ulnare and os carpi radiale. The phalanx proximalis digiti majoris had a triangular shape on the dorsal side and two blade-shaped phalanxes. The bones that make up the structure of the Dalmatian pelicans wing have significant similarities to other birds, but also to have many particular characteristics.(AU)

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In this study, the bones forming the poultry skeleton of the Dalmatian pelican were macroscopically examined. For this purpose, three Dalmatian pelicans were used. In the Dalmatian pelicans, the shoulder girdle (Ossa cinguli membri thoracici) is formed by the scapula, os coracoideum and clavicula bones. The scapula bone was short and flat. The humerus was a long bone with a cylindrical, pneumatic structure. Os corocoideum was also in the processus coracoideus tuber. Radius formed a joint with the ulna, and presented a slight slope from proximal to distal direction. Ossa carpi bones (skeleton manus) were composed of os carpi ulnare and os carpi radiale. The phalanx proximalis digiti majoris had a triangular shape on the dorsal side and two blade-shaped phalanxes. The bones that make up the structure of the Dalmatian pelicans wing have significant similarities to other birds, but also to have many particular characteristics.

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Lead (Pb) effects on testis histology, as well as sperm quality and oxidative status were evaluated in male Chestnut Capped Blackbird (Chrysomus ruficapillus). Wild blackbirds were captured, immediately sampled (field group) or kept in captivity and treated with a single intraperitoneal injection of saline solution (control) or saline solution with Pb acetate (50 or 100 mg/kg Pb). Seven days after injection, whole blood, ductus deferens and testis samples were collected. Increased Pb concentrations were observed in whole blood and testis of Pb-exposed blackbirds with respect to those from field and control blackbirds. Sperm cells of Pb-exposed blackbirds showed loss of membrane integrity, mitochondrial functionality, and DNA integrity. Also, oxidative damage was observed in testis of blackbirds injected with 100 mg/kg Pb. These findings indicate that Pb is accumulated in testis of C. ruficapillus, inducing severe morphological and biochemical injury that can compromise the reproductive performance of male blackbirds. Although the exposure scenario (Pb acetate, high dosage and intraperitoneal injection) tested in the present study would likely not occur in the wild, it was adequate to show potential and relevant toxic effects of Pb in wild birds.

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Sicalis luteola occurs from Mexico to South America. In the Northeastern Brazilian region its biology, population dynamics and threats are poorly known. The subspecies S. luteola luteiventris apparently migrates northward during austral winter. The specific aims of this work were: 1) to verify the seasonality of the species; 2) to analyze information on molting and breeding, and 3) to check the main threats to this bird in northeastern Brazil. The highest number of records were in March, April, and May (51.12%) and the lowest in November and December (3%).We found a greater population peak in April in the states of Rio Grande do Norte and Cearل, and in April and May in Pernambuco. In Paraيba there was not an apparent seasonal variation in frequency. We captured 66 individuals, all adults, being 38 males and 28 females. 30% of the captured birds showed contour feathers molt, mainly on the head. A total of 23 individuals had brood patch, all being females. Six nests were found and four contained two to three eggs. We found that the main threat is the illegal trade. Our findings may support conservation plans for this bird in the region.(AU)

Sicalis luteola ocorre do México a América do Sul. No Nordeste do Brasil sua biologia, dinâmica populacional e ameaças sمo pouco conhecidas. A subespécie S. luteola luteiventris aparentemente migra em direçمo ao norte durante o inverno austral. Os objetivos especيficos deste trabalho foram: 1) verificar a sazonalidade da espécie, 2) obter informaçُes referentes a muda e reproduçمo, e 3) verificar quais as principais ameaças. Os meses com os maiores nْmeros de registros foram março, abril e maio (51,12%), enquanto os meses de novembro e dezembro foram os menos representativos (3%). Foi encontrado um grande pico populacional no mês de abril nos estados do Rio Grande do Norte e Cearل, e em abril e maio em Pernambuco. Na Paraيba nمo houve uma variaçمo sazonal marcante. Foram capturados 66 indivيduos, todos adultos, sendo 38 machos e 28 fêmeas. 30% das aves capturadas apresentaram muda nas penas de contorno, principalmente na cabeça. Um total de 23 indivيduos apresentou placa de incubaçمo, sendo todas fêmeas. Seis ninhos foram encontrados, quatro deles continham dois ou três ovos. A principal ameaça a espécie no Nordeste é o comércio ilegal de aves silvestres. Este trabalho fornece importantes ferramentas para subsidiar planos de conservaçمo para essa ave na região.(AU)

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The Thamnophilidae are one of the most speciose Neotropical bird families, yet aspects of their natural history remain poorly documented. Here we provide information on breeding phenology, the length of incubation and nestling periods, parental care, and nesting success of the Star-throated Antwren, Rhopias gularis, an Atlantic Forest endemic. The data are discussed in light of life history theories. We found 27 active nests during two breeding seasons (2013/2014 and 2014/2015) at Carlos Botelho State Park in southeastern Brazil. Nesting activities were observed from September to January. Incubation and nestling periods lasted 16.8 ± 0.6 and 11.0 ± 0.86 days, respectively, as with most other antbirds. Males and females shared equally in incubation and nestling provisioning. The small clutch size of two eggs is that most commonly found in tropical birds and is hypothesized to have evolved due to increased nest predation rates. However, our data was not consistent with this hypothesis as the nest survival probability was high (57%). This is one of only a handful of studies that provide comprehensive information on the breeding biology of a Thamnophilid species in undisturbed habitat.(AU)

A Família Thamnophilidae compreende as diversas espécies de chocas e papa-formigas e compõem um dos maiores grupos de aves neotropicais. Apesar do elevado número de espécies, aspectos da história natural permanecem pouco documentados. No presente estudo são fornecidas informações sobre fenologia reprodutiva, duração dos períodos de incubação e permanência dos filhotes no ninho, cuidado parental e sucesso reprodutivo da choquinha-de-garganta-pintada, Rhopias gularis, endêmica da Mata Atlântica, enfocando teorias de história de vida. Foram encontrados 27 ninhos ativos durante duas temporadas reprodutivas (2013/2014 e 2014/2015) no Parque Estadual Carlos Botelho, no sudeste do Brasil. Atividades de nidificação foram observadas de setembro a janeiro. Períodos de incubação e permanência dos filhotes nos ninhos duraram 16.8 ± 0.6 e 11.0 ± 0.86 dias, respectivamente, sendo similares aos de outras chocas e papa-formigas. Machos e fêmeas dividiram as funções de incubação e alimentação dos ninhegos em taxas similares. As ninhadas de dois ovos seguem o padrão mais comum para Passseriformes tropicais, mas os dados apresentados não se mostraram consistentes com a hipótese de que a evolução de ninhadas menores está relacionada às altas taxa de predação de ninhos nesta região, uma vez que foi observada alta probabilidade de sobrevivência (57%). O presente estudo é um dos poucos a proporcionar informações abrangentes sobre a biologia reprodutiva de um Thamnophilidae em uma área preservada.(AU)

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The Saffron-cowled Blackbird, Xanthopsar flavus (Gmelin, 1788), is a globally vulnerable icterid endemic to grasslands and open areas, and a priority species for research and conservation programs. This contribution provides information on the population size, habitat, behavior, breeding biology and nest success of X. flavus in two conservation units (CUs) in Viamão, state of Rio Grande do Sul, Brazil: the Environmental Protection Area Banhado Grande, and the Wildlife Refuge Banhado dos Pachecos, classified as an “Important Bird Area”. Searches for X. flavuswere carried out mainly in open areas, the type of habitat favored by the species. Outside the breeding season individual behavior was recorded by the ad libitum method; during the breeding season, selected X. flavus pairs were observed following the sequence sampling method. The research areas were visited once a month, totaling approximately 530 hours of observations (September 2014 to June 2016) over 84 days, which included two breeding seasons. The species was observed across all months (not necessarily within the same year) and several X. flavusflocks were encountered, some with more than one hundred individuals (range = 2-137). Additionally, the behavior and feeding aspects, habitat use and breeding information on X. flavus were recorded. Two breeding colonies were found, and eleven nests were monitored. The estimated nesting success was 10% in Colony 1, but zero in Colony 2, where all eggs and nestlings were predated. Saffron-cowled Blackbirds were recorded in mixed flocks, mostly with Pseudoleistes guirahuro (Vieillot, 1819), P. virescens (Vieillot, 1819) and Xolmis dominicanus (Vieillot, 1823), the last also a globally endangered species. The collected information highlights the importance of CUs for the maintenance of X. flavus populations in the region. Maintenance of proper areas for feeding and breeding is necessary and urgent.[...](AU)

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Describing the interactions among cavity breeders is key to understanding their breeding ecology. In this study the temporal difference in cavity use between the great tit, Parus major (Linnaeus, 1758) and the small Japanese field mice, Apodemus argenteus (Temminck, 1845) is investigated, as a first step for clarifying the interaction between bird and mammal cavity breeders. Forty-seven nest boxes were installed on tree trunks in two urban forests of Hokkaido Island, Japan, and the breeding nests of tits and mice were found in 34 and 11 boxes, respectively. The tits used the nest boxes throughout the breeding season, from May to July. In contrast, mice breeding nests were found in the last half of the breeding season, from July to October. Our results showed that field mice rarely used boxes during the tits breeding season. This study provides important information, such as temporal differences in breeding site use between tits and mice.(AU)

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Describing the interactions among cavity breeders is key to understanding their breeding ecology. In this study the temporal difference in cavity use between the great tit, Parus major (Linnaeus, 1758) and the small Japanese field mice, Apodemus argenteus (Temminck, 1845) is investigated, as a first step for clarifying the interaction between bird and mammal cavity breeders. Forty-seven nest boxes were installed on tree trunks in two urban forests of Hokkaido Island, Japan, and the breeding nests of tits and mice were found in 34 and 11 boxes, respectively. The tits used the nest boxes throughout the breeding season, from May to July. In contrast, mice breeding nests were found in the last half of the breeding season, from July to October. Our results showed that field mice rarely used boxes during the tits’ breeding season. This study provides important information, such as temporal differences in breeding site use between tits and mice.

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The Saffron-cowled Blackbird, Xanthopsar flavus (Gmelin, 1788), is a globally vulnerable icterid endemic to grasslands and open areas, and a priority species for research and conservation programs. This contribution provides information on the population size, habitat, behavior, breeding biology and nest success of X. flavus in two conservation units (CUs) in Viamão, state of Rio Grande do Sul, Brazil: the Environmental Protection Area Banhado Grande, and the Wildlife Refuge Banhado dos Pachecos, classified as an “Important Bird Area”. Searches for X. flavuswere carried out mainly in open areas, the type of habitat favored by the species. Outside the breeding season individual behavior was recorded by the ad libitum method; during the breeding season, selected X. flavus pairs were observed following the sequence sampling method. The research areas were visited once a month, totaling approximately 530 hours of observations (September 2014 to June 2016) over 84 days, which included two breeding seasons. The species was observed across all months (not necessarily within the same year) and several X. flavusflocks were encountered, some with more than one hundred individuals (range = 2-137). Additionally, the behavior and feeding aspects, habitat use and breeding information on X. flavus were recorded. Two breeding colonies were found, and eleven nests were monitored. The estimated nesting success was 10% in Colony 1, but zero in Colony 2, where all eggs and nestlings were predated. Saffron-cowled Blackbirds were recorded in mixed flocks, mostly with Pseudoleistes guirahuro (Vieillot, 1819), P. virescens (Vieillot, 1819) and Xolmis dominicanus (Vieillot, 1823), the last also a globally endangered species. The collected information highlights the importance of CUs for the maintenance of X. flavus populations in the region. Maintenance of proper areas for feeding and breeding is necessary and urgent.[...]

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The Collared Crescentchest Melanopareia torquata is a poorly known and inconspicuous species of open savannas and grasslands in central Brazil, Paraguay and Bolivia. Three subspecies are currently recognized, but their taxonomic limits, ranges and conservation status are far from well-established. This paper analyses individual and geographic variation in this species on the basis of body measurements and plumage coloration of 119 specimens. A clinal pattern of body size variation and considerable mensural overlap precludes a clear-cut separation between the two subspecies restricted to Brazil, and there is evidently sexual dichromatism in some Brazilian populations. However, M. t. bitorquata shows highly distinct plumage features in parapatry with other forms, strongly suggesting it should be treated as a full species.

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The Cinnamon Tanager Schistochlamys ruficapillus inhabits semi-open grassy country, primarily in Brazil south of Amazonia. Three subspecies are currently recognized, one of which, S. r. sicki, is poorly known and endemic to the central Brazilian savannas (Cerrado). This paper analyses individual and geographic variation in this species on the basis of body measurements and plumage coloration. Larger birds are usually found farther south and at higher elevations, while smaller birds are found farther north and at lower elevations, as predicted by Bergmann's rule. Nevertheless, some unexpectedly small individuals (referable to S. r. sicki) can be found in central Brazil. Individual and geographical variation in plumage coloration is substantial, but it is not closely tied to variation in body size. Therefore, given the large number of specimens intermediate between the three subspecies, we propose to consider the Cinnamon Tanager a monotypic but highly variable species. The recognition of three subspecies by previous taxonomists was due to small sample sizes associated with large gaps in sampling. 

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Phacellodomus Reichenbach, 1853, comprises nine species of Furnariids that occur in South America in open and generally dry areas. This study estimated the geographic distributions of Phacellodomus species in South America by ecological niche modeling. Applying maximum entropy method, models were produced for eight species based on six climatic variables and 949 occurrence records. Since highest climatic suitability for Phacellodomus species has been estimated in open and dry areas, the Amazon rainforest areas are not very suitable for these species. Annual precipitation and minimum temperature of the coldest month are the variables that most influence the models. Phacellodomus species occurred in 35 ecoregions of South America. Chaco and Uruguayan savannas were the ecoregions with the highest number of species. Despite the overall connection of Phacellodomus species with dry areas, species such as P. ruber, P. rufifrons, P. ferrugineigula and P. erythrophthalmus occurred in wet forests and wetland ecoregions.(AU)

Phacellodomus Reichenbach, 1853 é composto por nove espécies de furnarídeos que ocorrem na América do Sul em áreas abertas e geralmente secas. Este estudo objetivou estimar as distribuições geográficas das espécies de Phacellodomus utilizando modelagem de nicho ecológico. Os modelos foram desenvolvidos com base em seis variáveis climáticas e 949 registros de ocorrência de oito espécies, utilizando o algoritmo Maxent. Maior adequabilidade climática para as espécies de Phacellodomus foi estimada em áreas abertas e secas. Áreas úmidas na Amazônia não foram muito favoráveis para a ocorrência dessas espécies. A precipitação anual e a temperatura mínima do mês mais frio foram as variáveis que mais influenciaram os modelos. As espécies de Phacellodomus ocorreram em 35 ecorregiões da América do Sul. O Chaco e as savanas do Uruguai foram as ecorregiões com o maior número de espécies. Apesar da ampla ocorrência das espécies Phacellodomus em áreas secas, espécies como P. ruber, P. rufifrons, P. ferrugineigula e P. erythrophthalmus ocorreram em florestas úmidas e ecorregiões alagadas.(AU)

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Habitat loss and attendant fragmentation threaten the existence of many species. Conserving these species requires a straightforward and objective method that quantifies how these factors affect their survival. Therefore, we compared a variety of metrics that assess habitat fragmentation in bird ranges, using the geographical ranges of 127 forest endemic passerine birds inhabiting the Atlantic Forest of Brazil. A common, non-biological metric - cumulative area of size-ranked fragments within a species range - was misleading, as the least threatened species had the most habitat fragmentation. Instead, we recommend a modified version of metapopulation capacity. The metric links detailed spatial information on fragment sizes and spatial configuration to the birds' abilities to occupy and disperse across large areas (100,000+ km(2)). In the Atlantic Forest, metapopulation capacities were largely bimodal, in that most species' ranges had either low capacity (high risk of extinction) or high capacity (very small risk of extinction). This pattern persisted within taxonomically and ecologically homogenous groups, indicating that it is driven by fragmentation patterns and not differences in species ecology. Worryingly, we found IUCN considers some 28 of 58 species in the low metapopulation capacity cluster to not be threatened. We propose that assessing the effect of fragmentation will separate species more clearly into distinct risk categories than does a simple assessment of remaining habitat.

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The factors that affect survival until reproduction are essential to understanding the organization of life histories within and among species. Theory predicts, for example, that survival until reproduction influences the optimum level of reproductive investment by parents, which might partly explain prolonged parental care in species with high first-year survival. Tests and refinements of life-history theory have been hampered, however, by a lack of field-based estimates of pre-reproductive survival, especially for tropical species, which have been the subject of many comparative analyses. Tropical species are predicted to have higher first-year survival and delayed reproduction compared to Northern Hemisphere species. We estimated survival until reproduction, age at first reproduction, and sources of variation in juvenile survival in a Neotropical passerine, the Western Slaty-Antshrike (Thamnophilus atrinucha), in central Panama. We observed that fledged antshrikes had 76% survival through the dependent period and 48% survival to the age of 1 year; survival rate was lowest during the first week after leaving the nest. Timing of fledging within the breeding season, fledgling mass, and age at dispersal influenced survival, while sex of offspring and year did not. Individuals did not breed until two years of age, and post-fledging pre-reproductive survival was 41% of annual adult survival. High survival until reproduction in antshrikes balanced their low annual productivity, resulting in a stable population. Survival during the post-fledging period of dependence and the first year of independence in the Western Slaty-Antshrike exceeded estimates for Northern Hemisphere species. This difference appears to be associated with the extended post-fledging parental care, delayed dispersal, low costs of dispersal, and the less seasonal environment of antshrikes.

Assuntos

RESUMO

Causes of interspecific variation in growth rates within and among geographic regions remain poorly understood. Passerine birds represent an intriguing case because differing theories yield the possibility of an antagonistic interaction between nest predation risk and food delivery rates on evolution of growth rates. We test this possibility among 64 Passerine species studied on three continents, including tropical and north and south temperate latitudes. Growth rates increased strongly with nestling predation rates within, but not between, sites. The importance of nest predation was further emphasized by revealing hidden allometric scaling effects. Nestling predation risk also was associated with reduced total feeding rates and per-nestling feeding rates within each site. Consequently, faster growth rates were associated with decreased per-nestling food delivery rates across species, both within and among regions. These relationships suggest that Passerines can evolve growth strategies in response to predation risk whereby food resources are not the primary limit on growth rate differences among species. In contrast, reaction norms of growth rate relative to brood size suggest that food may limit growth rates within species in temperate, but not tropical, regions. Results here provide new insight into evolution of growth strategies relative to predation risk and food within and among species.

Assuntos

RESUMO

Long embryonic periods are assumed to reflect slower intrinsic development that are thought to trade off to allow enhanced physiological systems, such as immune function. Yet, the relatively rare studies of this trade-off in avian offspring have not found the expected trade-off. Theory and tests have not taken into account the strong extrinsic effects of temperature on embryonic periods of birds. Here, we show that length of the embryonic period did not explain variation in two measures of immune function when temperature was ignored, based on studies of 34 Passerine species in tropical Venezuela (23 species) and north temperate Arizona (11 species). Variation in immune function was explained when embryonic periods were corrected for average embryonic temperature, in order to better estimate intrinsic rates of development. Immune function of offspring trades off with intrinsic rates of embryonic development once the extrinsic effects of embryonic temperatures are taken into account.

Assuntos