91 research outputs found
Life history notes on the Oriole-blackbird (<i>Gymnomystax mexicanus</i> ) in Venezuela
En la parte septentrional de América del Sur, el Tordo Maicero (<i> Gymnomystax tnexicanus</i> ) habita potreras, sabanas, plantaciones, otros parajes escasamente albolados. Vuela en bandadas pequeñas, en farmación abierta. Descansa en las copas de los árbales, pero para buscar comida desciende a la tierra, donde avanzando las pies alternativamente. Se alimenta con insectas, gusanos, lombrices, ranas pequeñas, etc., y también con frutas pequeñas que coge en los árboles. Su canto es chillón, y parece que le faltan notas dulces. Al principio de junio, una pareja empezó a construir su nidó entre las bases de las frondas de una palma alta en un repasto abierto, en el estado de Carabobo, Venezuela. Las materiales se recogieron de la tierra, principalmente por la hembra, aunque el macho ayudó un poco. El trabajo duró por lo menos 10 días. El nido era una taza abierta, de construcción floja, compuesto principalmente de los tallos de hojas compuestas, sobre un cimiento de pajas largas y gruesas. La hembra depositó tres huevos, de un azul claro, con manchas irregulares y puntos de negro y lila. Sóla ella incubaba, quedándose en el nido desde un cuarto de hora hasta casi dos horas sin interrupción y calentando los huevos por un 65 por ciento del período diurno. El macho era atento, acompañando a la hembra cuando ella regresó a la palma que contenía el nido, posándose en un árbol cercano mientras ella inculbaba, y de vez en cuando visitaba el nido. Los pichones nacieran con unas pocos plumones largos de color gris. El interior de sus bocas era rojo morado. Los dos padres les traían camida, desde el principio cargándola visiblemente en el pico. Las artículos de mayor tamaño, como ranas pequeñas, se traían uno por uno, pero varios gusanos ó lombrices se cargan juntos. Cuanda maiceros errantes se paraban cerca de la palma que contenía el nido, los padres protestaban suavemente, o más bien ignoraban a los visitantes. Esta especie casi no defiende su territorio. Aunque en su plumaje dorado y negro el Tordo Maicero se parece mucho a las arapéndulas del génera <i>Icterus</i> , en su voz, manera de buscar comida y nidificación demuestra más afinidad a los tordos y clarineros (<i>Quiscalus</i> , <i>Cassidix</i> , etc.).Widely distributed in northern South America, the Oriole·Blackbird inhahits open country with scattered trees, over which it flies in small, loose flocks. It rests in the treetops but forages chiefly on the ground, over which it walks with alternately advancing feet, gathering insects, caterpillars, worms, small frogs, and the like. It also plucks small fruits from trees. lts song is screechy or scratchy, and no melodious utterances were heard. In early June, a pair started a nest amid the bases of the leafl.stalks of a tall yagua palm growing in open pasture. The materials were gathercd from the ground, chiefly by the female, with the male helping occasionally. Building continued for at least 10 days. The nest was a loosely constructed open bowl, composed largely of the black, curving rachises of the compound leaves of an acacia·like tree, on a foundation of long, coarse straws, and smaller fragments of vegetation. The female laid three light blue eggs, marked with irregular blotches and speckles of black and lilac. She alone incubated, sitting from a quarter·hour to nearly two hours continuously and covering her eggs for 65 per cent of the daytime. Her mate was attentive, escorting her back to the nest tree, perching nearby while she incubated, and from time to time visiting the nest. The nestlings hatched with sparse but long, gray down; and the interior oi their mouths was purplish red. Both parents fed them, carrying the food visibly in their bills. Larger items, such as small frogs, were brought singly, but several worms or caterpillars were often carried together. When traspassing Oriole·Blackbirds perched near the nest tree, the parents protested mildly or not at all. This species is at most weakly territorial. Although in its golden and black plumage the Oriole.Blackbil'd resembles the orioles of the genus <i>Icterus</i> , in voice, mode of foraging, and nidification it more closely resembles the blackbirds and grackles (<i>Quiscalus</i> , <i>Cassidix</i> , etc.)
Biocompatibility: a Criterion for Conservation
A rich ecosystem Iike a tropical rain forest contains three categories of organisms: ( 1) the sustainer green photosynthetic plants of a1l growth forms, theír poIlinators, seed dispersers, and próteétors'from injurious insects, and mostIy obscure decomposers Cif dead malter that replenish the soil's fertility; (2) the associates or "guests", a diverse group that appears to be rleither necessary foc the maintenance of the ecosystem nor injurious to it; and (3) the "enemies", predators great andsmall, parasites externa! and interna!, pathogens, etc. that torture, mutilate, oc destroy membersof the fmt two categories, which coexist harmoníously, rarely injuring on¡; another. Iurge conservationists. to give preferentia! treatment to these comp¡¡tible categories, ceasing to apply inadequate resources to theprotection oc increase of members of the third category, if nor trying to eliminate sorne of them. By promoting biocompatibility, or compatible biodiversity, instead of biodiversity of undefined limits, we might rnake a more harmonious, productive, and enjoyable natural world.A rich ecosystem Iike a tropical rain forest contains three categories of organisms: ( 1) the sustainer green photosynthetic plants of a1l growth forms, theír poIlinators, seed dispersers, and próteétors'from injurious insects, and mostIy obscure decomposers Cif dead malter that replenish the soil's fertility; (2) the associates or "guests", a diverse group that appears to be rleither necessary foc the maintenance of the ecosystem nor injurious to it; and (3) the "enemies", predators great andsmall, parasites externa! and interna!, pathogens, etc. that torture, mutilate, oc destroy membersof the fmt two categories, which coexist harmoníously, rarely injuring on¡; another. Iurge conservationists. to give preferentia! treatment to these comp¡¡tible categories, ceasing to apply inadequate resources to theprotection oc increase of members of the third category, if nor trying to eliminate sorne of them. By promoting biocompatibility, or compatible biodiversity, instead of biodiversity of undefined limits, we might rnake a more harmonious, productive, and enjoyable natural world
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