903 resultados para birds of prey
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The feeding habits of two major species of sole, the common sole Solea vulgaris Quensel, 1806 and the Senegalese sole Solea senegalensis Kaup, 1858 were studied in the lower estuary of the Guadiana River (Algarve, southern Portugal). An evaluation of the number, weight, and feeding coefficient of prey types showed that S. vulgaris feed on a limited variety of prey (only Polychaeta and Tanaidacea) and present low-intensity feeding activity, with small differences in diet between seasons. S. senegalensis also have a low-diversity diet (with only one more taxa, Amphipoda), but exhibit more intense feeding activity which varies seasonally, although with little seasonal variation in the relative importance of the main preys. The diet composition of these two species suggests feeding specialization.
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Phenotypic differences within a species significantly contribute to the variation we see among plants and animals. Plasticity as a concept helps us to understand some of this variation. Phenotypic plasticity plays a significant role in multiple ecological and evolutionary processes. Because plasticity can be driven by the environment it is more likely to produce beneficial alternative phenotypes than rare and often deleterious genetic mutations. Furthermore, differences in phenotypes that arise in response to the environment can affect multiple individuals from the same population (or entire populations) simultaneously and are therefore of greater evolutionary significance. This allows similar, beneficial alternative phenotypes to increase quickly within a single generation and allow new environments to produce and select for new phenotypes instantly. The direction of the present thesis is to increase our understanding of how phenotypic plasticity, coupled with contrasting environmental conditions, can produce alternative phenotypes within a population. Plasticity provides a source of variation for natural selection to act upon, and may lead to genetic isolation as a by-product. For example, there are multiple cases of polymorphic populations of fish, where groups belonging to multiple isolated gene pools, have arisen in sympatry. Here it is shown that although plasticity is important in sympatric speciation events, plasticity alone is not responsible for the frequency in which sympatric polymorphic populations occur. The most frequently observed differences among sympatric polymorphic populations are morphological differences associated with parts of the anatomy used in the detection, handling and capture of prey. Moreover, it is shown here that there are physiological effects associated with foraging on alternative prey that may significantly contribute towards ecological speciation. It is also shown in this study that anthropogenic abiotic factors can disrupt developmental processes during early ontogeny, significantly influencing morphology, and therefore having ecological consequences. Phenotypic structuring in postglacial fish is most frequently based around a divergence towards either pelagic or littoral benthic foraging specialisms. Divergences that deviate from this pattern are of greater scientific interest as they increase our understanding of how evolutionary processes and selection pressures work. Here we describe a rare divergence not based around the typical pelagic/littoral benthic foraging specialisms. Finally, in this study, the effectiveness of local level conservation policy shows that species of fish which are highly variable in their life history strategies are harder to effectively manage and often poorly represented at a local level.
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Although on a local scale Iberian lynx distribution is determined by the availability of prey rabbits, recent modelling analyses have uncovered broad-scale disagreements between these two species’ distribution trends. These analyses showed also that the lynx had become restricted to only a fraction of the rabbit’s genetic diversity, and that this could be jeopardising its survival in the face of environmental hazards and uncertainty. In the present paper, a follow-up was carried out through the building of lynx and rabbit distribution models based on the most recent Spanish mammal atlas. Environmental favourability values for lynx and rabbit were positively correlated within the lynx’s current distribution area, but they were negatively correlated within the total Spanish area where lynx used to occur in the 1980’s. Environmental favourability for rabbits was significantly higher where lynx maintains reproductive populations than where it recently disappeared, indicating that rabbit favourability plays an important role and can be a good predictor of lynx persistence. The lynx and rabbit models were extrapolated to predict favourable areas for both species in Spain as well as in Portugal, on the original scale of the distribution data (10x10 km) and on a 100 times finer spatial resolution (1x1 km). The lynx and rabbit models were also combined through fuzzy logic to forecast the potential for lynx occurrence incorporating information on favourable areas for its main prey. Several areas are proposed as favourable for lynx expansion or re-introduction,
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Kiwi are rare and strictly protected birds of iconic status in New Zealand. Yet, perhaps due to their unusual, nocturnal lifestyle, surprisingly little is known about their behaviour or physiology. In the present study, we exploited known correlations between morphology and physiology in the avian inner ear and brainstem to predict the frequency range of best hearing in the North Island brown kiwi. The mechanosensitive hair bundles of the sensory hair cells in the basilar papilla showed the typical change from tall bundles with few stereovilli to short bundles with many stereovilli along the apical-to-basal tonotopic axis. In contrast to most birds, however, the change was considerably less in the basal half of the epithelium. Dendritic lengths in the brainstem nucleus laminaris also showed the typical change along the tonotopic axis. However, as in the basilar papilla, the change was much less pronounced in the presumed high-frequency regions. Together, these morphological data suggest a fovea-like overrepresentation of a narrow high-frequency band in kiwi. Based on known correlations of hair-cell microanatomy and physiological responses in other birds, a specific prediction for the frequency representation along the basilar papilla of the kiwi was derived. The predicted overrepresentation of approximately 4-6 kHz matches potentially salient frequency bands of kiwi vocalisations and may thus be an adaptation to a nocturnal lifestyle in which auditory communication plays a dominant role.
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El presente trabajo aporta información de base para el seguimiento y evaluación de la biodiversidad de las aves a escala local o regional. Para la realización de la lista, hemos tenido como punto de referencia la Lista sistemática de las aves de la provincia de Buenos Aires de N. Bó y C. Darrieu 1991 y Las aves de la provincia de Buenos Aires: distribución y estatus de T. Narosky y A. Di Giácomo 1993. La presente enumeración considera todas las especies de aves que habitan la provincia de Buenos Aires, es decir aquellas que nidifican o que pasan gran parte del año en la misma. Se excluyen, por lo tanto, aquellas especies accidentales y ocasionales. Los datos se basan en citas bibliográficas recientes, material de colección y observaciones de campo realizadas por los autores. Para indicar la distribución geográfica de las aves se ha seguido el esquema propuesto por Ringuelet y Arámburu (1957, Enumeración sistemática de los Vertebrados de la Provincia de Buenos Aires). Según el mismo se divide a la provincia en cuatro áreas: la 1 posee una avifauna de tipo subtropical; en la 2 se encuentran aves pampeanas con ingresión de especies de la Provincia Chaqueña (Distrito Occidental); en la 4 la avifauna presenta un gran número de especies que llegan por el sur desde la Provincia del Monte (Distrito Meridional) y de la Provincia Patagónica (Distrito Occidental); el área 3 es de transición con aporte de especies de las otras zonas. La presente lista comprende los nombres científicos tomados de Altman & Swift (1989), Checklist of the Birds of South America. Para los nombres vulgares se siguió a Navas et al (1991). Lista Patrón de Nombres Comunes de las Aves Argentinas. Se incluye además una lista de las especies exóticas naturalizadas. (Text is in Spanish.
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To be in compliance with the Endangered Species Act and the Marine Mammal Protection Act, the United States Department of the Navy is required to assess the potential environmental impacts of conducting at-sea training operations on sea turtles and marine mammals. Limited recent and area-specific density data of sea turtles and dolphins exist for many of the Navy’s operations areas (OPAREAs), including the Marine Corps Air Station (MCAS) Cherry Point OPAREA, which encompasses portions of Core and Pamlico Sounds, North Carolina. Aerial surveys were conducted to document the seasonal distribution and estimated density of sea turtles and dolphins within Core Sound and portions of Pamlico Sound, and coastal waters extending one mile offshore. Sea Surface Temperature (SST) data for each survey were extracted from 1.4 km/pixel resolution Advanced Very High Resolution Radiometer remote images. A total of 92 turtles and 1,625 dolphins were sighted during 41 aerial surveys, conducted from July 2004 to April 2006. In the spring (March – May; 7.9°C to 21.7°C mean SST), the majority of turtles sighted were along the coast, mainly from the northern Core Banks northward to Cape Hatteras. By the summer (June – Aug.; 25.2°C to 30.8°C mean SST), turtles were fairly evenly dispersed along the entire survey range of the coast and Pamlico Sound, with only a few sightings in Core Sound. In the autumn (Sept. – Nov.; 9.6°C to 29.6°C mean SST), the majority of turtles sighted were along the coast and in eastern Pamlico Sound; however, fewer turtles were observed along the coast than in the summer. No turtles were seen during the winter surveys (Dec. – Feb.; 7.6°C to 11.2°C mean SST). The estimated mean surface density of turtles was highest along the coast in the summer of 2005 (0.615 turtles/km², SE = 0.220). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2005 (0.016 turtles/km², SE = 0.009). The mean seasonal abundance estimates were always highest in the coastal region, except in the winter when turtles were not sighted in either region. For Pamlico Sound, surface densities were always greater in the eastern than western section. The range of mean temperatures at which turtles were sighted was 9.68°C to 30.82°C. The majority of turtles sighted were within water ≥ 11°C. Dolphins were observed within estuarine waters and along the coast year-round; however, there were some general seasonal movements. In particular, during the summer sightings decreased along the coast and dolphins were distributed throughout Core and Pamlico Sounds, while in the winter the majority of dolphins were located along the coast and in southeastern Pamlico Sound. Although relative numbers changed seasonally between these areas, the estimated mean surface density of dolphins was highest along the coast in the spring of 2006 (9.564 dolphins/km², SE = 5.571). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2004 (0.192 dolphins/km², SE = 0.066). The estimated mean surface density of dolphins was lowest along the coast in the summer of 2004 (0.461 dolphins/km², SE = 0.294). The estimated mean surface density of dolphins was lowest in Core and Pamlico Sounds in the summer of 2005 (0.024 dolphins/km², SE = 0.011). In Pamlico Sound, estimated surface densities were greater in the eastern section except in the autumn. Dolphins were sighted throughout the entire range of mean SST (7.60°C to 30.82°C), with a tendency towards fewer dolphins sighted as water temperatures increased. Based on the findings of this study, sea turtles are most likely to be encountered within the OPAREAs when SST is ≥ 11°C. Since sea turtle distributions are generally limited by water temperature, knowing the SST of a given area is a useful predictor of sea turtle presence. Since dolphins were observed within estuarine waters year-round and throughout the entire range of mean SST’s, they likely could be encountered in the OPAREAs any time of the year. Although our findings indicated the greatest number of dolphins to be present in the winter and the least in the summer, their movements also may be related to other factors such as the availability of prey. (PDF contains 28 pages)
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O processo de miniaturização em anuros pode ter implicações ecológicas como, por exemplo, a redução no tamanho da ninhada produzida pelas fêmeas, o aumento do tamanho relativo dos ovos e o desenvolvimento direto. O consequente reduzido tamanho da boca tende também a constituir um fator limitante no consumo de presas por estes pequenos anuros, tornando acessível ao consumo apenas uma gama restrita de presas diminutas. Assim, estudamos parâmetros da ecologia de uma população do anuro Brachycephalus didactylus, em uma área de Mata Atlântica no sul do Espírito Santo, objetivando ampliar o conhecimento sobre tais parâmetros que compreenderam o dimorfismo sexual, algumas características da reprodução, a dieta e a relação com a disponibilidade de atrópodos no folhiço e uso do microhabitat. A amostragem dos dados ocorreu durante um ano, nas estações seca e chuvosa. Brachycephalus didactylus possuiu dimorfismo sexual, com fêmeas sendo maiores do que os machos. O maior tamanho atingido pelas fêmeas provavelmente resulta da seleção intrassexual atuando nas fêmeas para favorecer um maior investimento na massa dos ovos, já que a espécie possui um tamanho de ninhada consideravelmente reduzido (um a dois ovos). A dieta de B. didactylus foi composta por um espectro relativamente amplo de presas (17 itens), tendo elevadas proporções de pequenas presas como Acari e Collembola. O consumo de Formicidae (formigas) foi evitado por B. didactylus, apesar de essa presa ser a mais abundante no folhiço, o que categorizou o anuro como um "especialista em não comer formigas" ("non-ant specialist", sensu Toft 1980a). O reduzido tamanho da boca nas fêmeas de B. didactylus limitou o tamanho máximo de presas passíveis de serem ingeridas pelo anuro e restringindo-o ao consumo de presas pequenas, com maiores indivíduos consumindo um número maior de presas. Por fim, B. didactylus apresentou uma utilização essencialmente horizontal do hábitat, sendo mais frequentemente encontrado sobre o folhiço no chão da mata.
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Book Reviews: Darwin's Finches by David Lack. Field Guide to the Birds of the Galapagos by Michael Harris.
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Stomach samples from three rockfish species, yellowtail (Sebastes f lavidus), widow (S. entomelas), and canary (S. pinniger) rockfish, seasonally collected off the Pacific Northwest in 1998 and 1999, provided quantitative information on the food habits of these species during and after the 1997–98 El Niño event. Although euphausiids were the most common major prey of all three predators, gelatinous zooplankton and fishes were the most commonly consumed prey items during some seasonal quarters. The influence of the El Niño event was evident in the diets. Anomalous prey items, including the southern euphausiid species Nyctiphanes simplex and juveniles of Pacific whiting (Merluccius productus) frequently appeared in the diets in the spring and summer of 1998. The results of stomach contents analyses, based on 905 stomach samples from 49 trawl hauls during seven commercial fishing trips and from 56 stations during research surveys, were consistent with the timing of occurrence and the magnitude of change in biomass of some zooplankton species reported from zooplankton studies in the northern California Current during the 1997–98 El Niño. Our findings indicate that the observed variations of prey groups in some rockfish diets may be a function of prey variability related to climate and environment changes.
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Na Colômbia ocorrem 787 espécies de anfíbios. Por causa da preocupação com o estado de conservação de muitas dessas espécies, tem se sugerido que na Colômbia deveriam-se priorizar as pesquisas em taxonomia e ecologia em regiões sub-amostradas a fim de intensificar o conhecimento e conservação dos anfíbios colombianos. Baseados em uma análise cienciométrica de 319 trabalhos sobre a ecologia dos anfíbios colombianos publicados entre 1840 e 2014 (No Capítulo 1), identificamos as tendências nos esforços realizados em distintos temas de pesquisa, e a distribuição regional e taxonômica desses estudos. A maioria dos estudos (67%) foi realizada na região Andina colombiana em comparação com outras regiões naturais da Colômbia. Apenas 46% das espécies de anfíbios ocorrendo na Colômbia foi tratada nos estudos analizados, e a maioria (58%) delas é da região Andina. Entre as publicações analizadas identificamos 14 temas de pesquisa em ecologia, dos quais ecologia reprodutiva (26%), conservação de espécies (23%) e dieta (14%) foram os mais pesquisados. Nossos dados mostraram que na Colômbia há um considerável avanço na pesquisa sobre a ecologia dos anfíbios do país, mas ainda são necessários esforços para cobrir muitos vazios de informação para muitas regiões e para muitas espécies de anfíbios que possuem dados incipientes. No sudoeste da Cordilheira Ocidental colombiana há pouca informação ecológica sobre os anfíbios ali ocorrendo. A fim de saber alguns aspectos ecológicos dessas espécies, desenvolvimos três estudos sobre a diversidade e ecologia de anfíbios presentes na Reserva Natural Río Ñambí (a seguir RNRÑ). No Capítulo 2 apresentamos uma análise sistemática do gênero Andinophryne (Família Bufonidae), composto por três espécies, A. atelopoides, A. colomai (presente na RNRÑ) e A. olallai. As filogenias mostraram que Andinophryne está incorporado dentro de Rhaebo. Portanto, sinonimizamos Andinophryne sob Rhaebo e discutimos as sinapomorfias morfológicas putativas para Rhaebo. Além, fornecemos informações ecológicas e sobre o estado de conservação das três espécies incluídas na nova combinação taxonômica. No Capítulo 3 apresentamos uma lista de 19 espécies de anfíbios pertencentes a oito famílias, com uma dominância numérica da família Craugastoridae e do gênero Pristimantis. As espécies com a maior abundância relativa (> 25%) foram Pristimantis labiosus e P. verecundus. Sete diferentes modos de reprodução foram reconhecidos, com a maioria das espécies (68%) possuindo desenvolvimento direto de ovos. Cinco (26%) das espécies registradas estão classificadas dentro das categorias de maior ameaça de extinção. Reportamos para sete espécies a extensão da faixa de distribuição geográfica latitudinal na Colômbia. No Capítulo 4 comparamos a dieta de jovens e adultos de P. labiosus para identificar se houve uma mudança ontogenética no tamanho de presa consumido com o aumento na largura da boca. A dieta foi composta por 19 categorias de presas (> artrópodes), com as duas classes de idade consumindo um similar espectro de categorias. Os jovens têm um nicho trófico maior (0,45) do que os adultos (0,25), com uma sobreposição de nicho relativamente baixa (0,39) entre eles. Apesar da diferencia na largura da boca entre jovens e adultos, não houve uma correspondente mudança ontogenética no tamanho de presa consumida. Consideramos P. labiosus como um predador generalista que parece consumer uma ampla gama de tipos e tamanhos de presas
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The harbor seal (Phoca vitulina) is a large-bodied and abundant predator in the Salish Sea ecosystem, and its population has recovered since the 1970s after passage of the Marine Mammal Protection Act and the cessation of bounties. Little is known about how this large predator population may affect the recovery of fish stocks in the Salish Sea, where candidate marine protected areas are being proposed. We used a bioenergetics model to calculate baseline consumption rates in the San Juan Islands, Washington. Salmonids (Oncorhynchus spp.) and herring (Clupeidae) were the 2 most energetically important prey groups for biomass consumed by harbor seals. Estimated consumption of salmonids was 783 (±380 standard deviation [SD]) metric tons (t) in the breeding season and 675 (±388 SD t in the nonbreeding season. Estimated consumption of herring was 646 (±303 SD) t in the breeding season and 2151 (±706 SD) t in the nonbreeding season. Rockfish, a depressed fish stock currently in need of population recovery, composed one of the minor prey groups consumed by harbor seals (84 [±26 SD] t in the nonbreeding season). The variables of seal body mass and proportion of prey in seal diet explained >80% of the total variation in model outputs. Prey groups, such as rockfish, that are targeted for recovery may still be affected by even low levels of predation. This study highlights the importance of salmonids and herring for the seal population and provides a framework for refining consumption estimates and their confidence intervals with future data.
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Few studies have quantified the extent of nocturnal cross-habitat movements for fish, or the influence of habitat adjacencies on nutrient flows and trophodynamics. To investigate the patterns of nocturnal cross-boundary movements of fish and quantify trophic connectivity, fish were sampled at night with gillnets set along the boundaries between dominant habitat types (coral reef/seagrass and mangrove/seagrass) in southwestern Puerto Rico. Fish movement across adjacent boundary patches were equivalent at both coral reefs and mangroves. Prey biomass transfer was greater from seagrass to coral reefs (0.016 kg/km) and from mangroves to seagrass (0.006 kg/km) but not statistically significant, indicating a balance of flow between adjacent habitats. Pelagic species (jacks, sharks, rays) accounted for 37% of prey biomass transport at coral reef/seagrass and 46% at mangrove/seagrass while grunts and snappers accounted for 7% and 15%, respectively. This study indicated that coral reefs and mangroves serve as a feeding area for a wide range of multi-habitat fish species. Crabs were the most frequent prey item in fish leaving coral reefs while molluscs were observed slightly more frequently than crabs in fish entering coral reefs. For most prey types, biomass exported from mangroves was greater than biomass imported. The information on direction of fish movement together with analysis of prey data provided strong evidence of ecological linkages between distinct adjacent habitat types and highlighted the need for greater inclusion of a mosaic of multiple habitats when attempting to understand ecosystem function including the spatial transfer of energy across the seascape.
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绿孔雀是国家I级重点保护鸟类. 在《Endangered Birds of the W orld-The ICBP Bird Red Data Book》(King, 1981)及《1990 IUCN Red List of Threatened Animals》中均将其列为易危种. 在CITES中被列入附录2. 据文献记载:绿孔雀在中国分布于云南(郑作新, 1987)和西藏东南部(尹秉高等, 1993). 历史上云南东南部的开远、建水和文山县曾记载有绿孔雀分布(《云南通志》, 明隆庆六年, 1572). 现代著作中(彭燕章等, 1987; 郑宝责等, 1987; 张帆等, 1987; 杨岚, 1989, 1991; 文贤继等, 1995; 杨晓君, 1995)记录云南省东南部的蒙自、金平、绿春、河口、弥勒、建水、石屏等7个县有绿孔雀分布. 另据当地群众反映在滇西北迪庆州发现有绿孔雀. 作者于1995年4-6月、11-12月和1996年4-6月在以往对绿孔雀分布现状调查(文贤继等, 1995)的基础上, 对云南东南部和西北部绿孔雀的分布现状及保护情况又进行了调查, 本次调查对绿孔雀在上述地区的分布状况进行了核实, 为今后的生态生物学研究和保护工作提供了有关资料。
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据Dickinson,E.C.,主编,2003年出版的“m Howard and Moore Gomplete Q蛐ofthe Birds of the World'’一书和2000。2008年的有关文献的记载,在1958~2008年的50年期间,全世界所描述发表鸟类的新种,计 有171种。以每10年中所发表的新种数进行统计比较,以1997~2007年期间所发表的新种为最多;按发现新种所属 目级分类阶元的统计比较,以雀形目发现的新种为最多;按地区进行统计比较,以南美洲发现的新种数为最多,非洲中南部地区和太平洋诸岛为次;在中国境内描记的新种有台湾短翅莺西哟脚嬲旋渤删、峨嵋柳莺场皿瞰灿mzden面、海南柳莺崩砌蚴‰肠砌船、峨嵋鹪莺岛匆船硎豳面、淡尾鹅莺崩锄船..toror、弄岗穗鹛&叻帕御赠删、 四川旋木雀眺砌婶删等7种,其中由中国鸟类学者描记的有四川旋木雀和弄岗穗鹛两种。这说明鸟类的宏 观分类研究,时至今日仍有研究的必要和发展空间。种下分类,是探讨同一个物种,随着分布区域的扩大,自然地 理环境条件的变化,而产生地区性分布种群的变异,以致新物种形成的途径,是宏观分类学研究一个物种的演化发 展。所以是当今鸟类分类研究的热点之一。据统计,1958—2008年的50年间,新描述发表的亚种数,约为1 129亚 种。繁殖区域分布较为广泛的种类,所描记的亚种较多。如岛鸫Turd.sp,hbcephaha分化有5l亚种之多。中国鸟类的 分类与区系地理学研究,大致可分为起步时期(1949年以前)、新中国建立之后的考察及宏观分类研究的总结整理 时期(1950—2005)和宏观与微观相结合的发展研究时期(1999年以后)等3个时期。郑作新所出版的《中国鸟类 分布名录》和《中国鸟类区系纲要》等专著,是中国鸟类宏观分类和区系地理学研究较为翔实的阶段性总结,为进 一步研究奠定了坚实的基础。
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