Browsing by Subject "Birds"

Now showing 1 - 3 of 3
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    Pineal concretions in turkey (Meleagris gallopavo) as a result of collagen-mediated calcification
    (Murcia : F. Hernández, 2009) Przybylska-Gornowicz, B.; Lewczuk, B.; Prusik, M.; Bulc, M.
    The intra-pineal calcification is a well-known phenomenon in mammals, however it is almost completely unknown in birds. The aim of the present work was to analyze morphology and genesis of the pineal concretions in the turkey. The studies were performed on the pineals collected from one-year-old turkeys (Meleagris gallopavo). In addition to standard morphological methods, the alizarin red S and potassium pyroantimonate methods were employed for localization of calcium at the light and electron microscopy level. In light microscopy, calcified concretions with diameters from 300 μm to 2 mm and quantities from 3 to 6 per gland were observed in all the examined pineals. They were stained red with alizarin S and showed the presence of collagen in Mallory's staining. Two types of cells were noted inside the concretion: polygonal and elongated ones. Using electron microscopy, three parts were distinguished within the calcification area. The peripheral part contained densely packed collagen fibrils, some elongated cells and numerous pyroantimonate precipitates demonstrating the presence of calcium ions. In the intermediate part, the fibrils were covered by almost continuous sheets of pyroantimonate precipitates and fused side by side. The central part showed an appearance of calcified hard tissue and showed an appearance of calcified hard tissue and contained some polygonal (osteocyte-like) cells. The obtained data demonstrated that the formation of the pineal concretions in the turkey is associated with the mineralization of collagen. This process is completely different from the mechanisms responsible for the formation of the concretions in the mammalian pineal.
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    Propuestas para el desarrollo y comercialización del turismo ornitológico en Extremadura
    (Murcia, Universidad de Murcia, Servicio de Publicaciones, 2011) Hernández Mogollón, José Manuel; Campón Cerro, Ana María; García Durán, José María
    El turismo ornitológico es una de las grandes apuestas en el desarrollo turístico de Extremadura dada su riqueza en aves. El número de empresas enfocadas a este segmento está creciendo, las agencias de viajes ya incluyen estos paquetes en sus programaciones y la administración turística regional promueve eventos como la Feria Internacional de Turismo Ornitológico (FIO) en Monfragüe, considerado punto de referencia mundial. Este trabajo trata de poner de manifiesto la relevancia de Extremadura como destino de turismo ornitológico aportando propuestas para su desarrollo y comercialización.
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    Vertebrates can be more important pollinators than invertebrates on islands: the case of Malva (=Lavatera) arborea L.
    (Oxford University Press, 2024-03-01) Robles, Cristina; Romero-Egea, Víctor; Traveset, Anna; Ruiz de Ybáñez Carnero, María del Rocío; Hervías Parejo, Sandra; Sanidad Animal
    Premise of the study: On islands, flowering plants tend to be more generalist in their pollination needs, as insects (the main pollinators of flowering plants) are underrepresented in these ecosystems compared to the mainland. In addition, some vertebrate species that are typically insectivorous or granivorous on the mainland are forced to broaden their diet and consume other resources such as nectar or pollen on the islands. The shrub Malva arborea, with its large and colourful flowers, attracts different groups of potential pollinators. This study aimed to compare the effectiveness of vertebrates versus insects in an insular population of M. arborea and to investigate its reproductive system. Methods: For three groups of taxa (insects, birds and lizards), we assessed the two components of pollination effectiveness: (i) the quantitative component (i.e. number of visits and number of flowers contacted) through direct observations of flowers; and (ii) the qualitative component (fruit and seed set, number and size of seeds and proportion of seedling emergence) through pollinator exclusion experiments. Key results: Vertebrates (birds and lizards) were quantitatively the most effective pollinators, followed by insects. However, when all three groups visited the flowers, fruit and seed set were higher than when any of them were excluded. We also found that M. arborea has hermaphrodite flowers and is able to reproduce by autogamy, although less efficiently than when pollinated by animals. Conclusions: Both vertebrates and insects play an important role in the reproduction of M. arborea. Although the plant does not need pollinators to produce seeds, its reproductive success increases when all pollinators are allowed to visit the flowers. Besides providing new information on M. arborea, these findings may help to better understand the role of different pollinator groups in the reproduction of other plant species, especially on islands where the co-occurrence of vertebrate and invertebrate pollination in the same plant species is usual.