38 resultados para Mimus saturninus
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Embora os estudos de frugivoria e dispersão de sementes sejam importantes para a realização de planos de manejo e recuperação de ambientes degradados, pouco tem sido pesquisado sobre o assunto no cerrado brasileiro. Neste trabalho são apresentados aspectos da frugivoria e dispersão das sementes de Ocotea pulchella Mart. (Lauraceae) por aves. Treze espécies de aves foram registradas consumindo os frutos de O. pulchella em 72 horas de observação focal, entre os meses de agosto e outubro de 1999, numa área de cerrado da região central do estado de São Paulo (21º58' S, 47º52' W), Brasil. As principais espécies potencialmente dispersoras foram o sabiá-pardão, Turdus leucomelas (Muscicapidae), o sabiá-docampo, Mimus saturninus (Mimidae), o bem-te-vi, Pitangus sulphuratus (Tyrannidae) e as guaracavas, Elaenia spp. (Tyrannidae). Não foram encontradas variações significativas no número de visitas nos diferentes intervalos de hora quando todas as espécies foram analisadas em conjunto e quando cada espécie foi analisada separadamente. Não houve variação significativa também no tempo de permanência sobre as plantas entre as diferentes espécies de aves. A taxa de consumo diferiu significativamente entre elas, tendo sido encontrada correlação positiva significativa entre o peso das diferentes espécies e o número médio de frutos consumidos por visita. O tempo de permanência sobre a planta e o número de frutos consumidos foram positivamente correlacionados para Elaenia spp., para a maria-cavaleira, Myiarchus tyrannulus (Tyrannidae) e para o sabiá-laranjeira, Turdus rufiventris (Muscicapidae). Embora espécies primariamente frugívoras não tenham sido observadas consumindo os frutos de O. pulchella, as espécies oportunistas pareceram favorecer a eficiência da dispersão, mantendo altas freqüências de visitas, altas taxas de consumo e permanecendo por curtos períodos de tempo sobre as plantas.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A nuclear or leader species is the one around which foraging activity is organized. In the campo-cerrado (Brazilian savannah) up to four bird species (Saltator atricollis, Cypsnagra hirundinacea, Mimus saturninus, and Neothraupis fasciata) may function as nuclear or leader species in mixed species flocks. The aim of this study was to assess the features shown by these nuclear species. I quantified parameters of sociality, communication and alertness of nuclear bird species in mixed flocks with different composition. Parameters related to sociality (mean intraspecific group size) and communication (frequency of contact calls) were not correlated with the leadership. on the other hand, the most alert species was in the front of a given mixed flock most of the time. The leader species spent more time in vigilance and gave most alarm calls due to approaching raptors earlier. The results of this study strongly suggest that the alertness of a species is the major character of nuclear bird species in mixed flocks of the campo-cerrado.
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Some plants are widely distributed, ranging in different vegetation types. Since bird distribution can be directly associated to vegetational cover, we expect that seed dispersers can also vary following phytophysiognomy for some ornithochorous plants. The purpose of this paper was to describe potential seed disperser birds of Talauma ovata (Magnoliaceae) in semideciduous Atlantic forest and cerrado fragments in south-east Brazil. In 79 h of focal observations we recorded 1085 visits of 25 different bird species consuming T. ovata diaspores. Although most bird species observed consuming T. ovata diaspores present generalist habits, they were potential seed dispersers, presenting high visits rate and do not staying a long time on the plants, favoring seed dispersal efficiency. Fruit consumption was not different between species in the study sites and the time spending on the plants was not different between species in semideciduous forest, but was different in cerrado. Agonistic encounters were observed mainly in the end of fruiting season, but was not relevant to decrease the number of seeds dispersed by birds. The occurrence of different potential seed dispersers between areas, such as Cyanocorax cristatellus (Corvidae), Schistochlamys ruficapillus (Emberizidae) and Mimus saturninus (Mimidae), which are endemic from the cerrado ecosystem and could rarely be found in semideciduous forest, suggests that seed dispersers can vary according to phytophysiognomy characteristics. Our results also indicate that the evolution of a generalist seed dispersal system such as observed for T. ovata can make possible the colonization of different ambients. Furthermore, the high number of visits recorded for both areas suggests that the fleshy arils of T. ovata are important feeding resources for birds.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Evalúa la situación en las islas Lobos de Afuera durante el período del 10 al 13 de diciembre de 2001, respecto a la gran presión pesquera por parte de buzos y marisqueros de Lambayeque y de Piura (Sechura), que hace peligrar la explotación sostenible del recurso pulpo. En ese sentido, el laboratorio costero llevó a cabo la verificación en la zona (lugar donde esta especie bentónica presenta gran abundancia) a fin de obtener datos biométricos y biológico-pesqueros que permitan determinar el estado del pulpo y recomendar, en base a ello, medidas de ordenamiento pesquero para evitar la depredación de la especie.
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Brinda información sobre los resultados de la estimación de la talla media de primera madurez y desove, así como la determinación del ciclo reproductivo del pulpo Octopus mimus. Los datos utilizados corresponden a muestreos de la pesquería artesanal en el área del Callao entre enero 1998 y enero 1999.
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La distribución de tallas de pulpo fluctuó entre 40 y 200 mm de longitud del manto. El peso promedio fue 588,20 g, el 85% de los ejemplares no superó el peso mínimo de extracción (1 kg). En hembras predominaron estadios en desarrollo (63%), madurez total (16%); en machos predominaron estadios en desove (64%) y maduros (28%). La mayor concentración del recurso se registró al norte de la isla El Ladrón y frente a isla Quita Calcal. Las tallas de percebes fluctuaron entre 1 y 40 mm de longitud carina-rostral (Lcr), 55% de ejemplares estuvieron maduros. El percebes estuvo distribuido en el intermareal rocoso entre 6°56’9’’S y 6°57’30,6’’S en un área de 887,50 m2. La biomasa se estimó en 3,06 t ±27,18% y la población en 0,42 millones de individuos ±47,30%; el stock de juveniles (<17 mm) fue 0,17 millones de ejemplares; el stock adulto (≥17 mm) estuvo constituido por 0,24 millones de individuos y 2,90 t de la biomasa.
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Detached from K. Akademie der Wissenschaften, Vienna. Philosophisch-historische Klasse. Sitzungsberichte, v.12, no.2, 1854.
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Includes bibliographical references.
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Trägerband: Inc. oct. 28; Vorbesitzer: Dominikanerkloster Frankfurt am Main
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The thrush beach, Mimus gilvus (Aves: Mimidae) is a passerine widely distributed in Central and South America. In Brazil occurs mainly in the areas of the resting and vegetation near the beach. In southeastern Brazil this species has disappeared, mainly due to urbanization. Many attributes of their reproductive biology are unknown, especially in relation to reproductive success. During the years 2010-2011, 2011-2012 and 2014-2015 were made visits to the area of restinga forest in Centro de Lançamento da Barreira do Inferno (CLBI), located between the cities of Natal and Parnamirim-RN (5 ° 54'S 35 ° 10'W ) where they were made systematic searches to trying describe reproductive biology of the characteristics of M. gilvus, estimate their reproductive success using the Mayfield method, and identify the main factors that influence their reproductive success in environment the resting. For this, forty fifth active nests monitored were used. Only during the breeding season of 2011-2012 and 2014-2015 were made systematic visits to the study area. The reproductive period ranged August to March. Clutch size ranged from two, three and six eggs (n = 22). Broods of two eggs were more common, with an average of eggs laid per nest of 2 ± 0,51 (n = 20 nests). The incubation period was approximately 13 ± 1,9 days (n = 11 nests). The period of stay of the nestlings was approximately 11 ± 1,6 days (n = 9 nests). With approximately 11 days old the nestlings were able to leave the nest. The apparent success was 37,8% and the success estimated by Mayfield method was 26,6%. Predation was the main cause of loss of nests in the study area. The daily survival rates (TDS) were obtained from 0,9593 incubation and 0,9313 for nestling period respectively. Survival estimates for each period was 0,5827 for incubation and 0,4571 for nestling period. The cumulative average rainfall for each month influenced negatively the hatching rates of M. gilvus nests. In addition, the number hatch eggs among the most rainy season (rainy season) and the period of lowest rainfall (dry season) were different. The number of lost nests of M. gilvus was lower in scrubs than cactus, which may account for the largest number of nests of this species found in scrubs. Survival rates in nestling period were lower compared with the incubation period. The fact that the survival rates nests of M. gilvus be lower in the nestling period compared to the incubation period may result from increased activity of adults during this phase of the nest, which in turn would increase predation rates. M. gilvus seems to avoid the rainy season during their reproduction, concentrated most of their nests in periods of low rainfall.
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Se realizó el análisis comparativo de los principales aspectos reproductivos del pulpo Octopus mimus Gould, 1852 entre las áreas de Callao y Chiclayo; utilizando bases de datos correspondientes a los muestreos quincenales de las capturas de la pesquería artesanal durante el año 2014. Se muestrearon 604 individuos (244 hembras y 360 machos) en Callao y 411 individuos (152 hembras y 259 machos) en Chiclayo. Este estudio tiene como objetivo aumentar el conocimiento sobre la biología reproductiva de la especie, y cómo se ve influenciada por las condiciones oceanográficas propias de un área. Se determinó que ambas poblaciones no siguen los parámetros de una distribución normal, y que son estadísticamente diferentes con relación a la longitud del manto. Callao muestra una talla media anual mayor que Chiclayo. La proporción anual de sexos fue a favor de los machos. Resalta el predominio de individuos hembras y machos maduros durante todo el año. La talla de madurez obtenida, confirma que los machos maduran a tallas menores que las hembras. La talla de desove mantiene la tendencia. El peso de madurez en ambos sexos se encontró por debajo del peso mínimo de captura (1 kg), pero el peso de desove de las hembras fue mayor a éste. El grado en que la condición del individuo se ve afectada por la reproducción, es más evidente y determinante en hembras. La especie muestra un crecimiento alométrico negativo. En machos está mejor definido el aumento del peso de la gónada en función de la longitud del manto. La influencia de los factores ambientales sobre el ciclo reproductivo es particular en cada área, lo que explica las diferencias en el biotipo y la estacionalidad de los eventos reproductivos.