Temperate forests are distributed over very extensivo areas in North America but in tropical Midd... more Temperate forests are distributed over very extensivo areas in North America but in tropical Middle America are limited to montane zones, and at the present time these montane forests are threatened by man because of overpopulation. I studied the structure and use of foliage of bird communities in montane temperate forests of , the Valley of Mexico. In August and September of 1981 I censused bird communities in six temperate forest study areas one each in oak woodland and pine-alder forest, and two each in pine forest and firforest using the variable circular-plot method. Overall bird densities were greater in broad-leaved forests than in coniferous forests. Species richness was similar between broad-leaved and pine forests but generally lower in fir forests. A similar trend was shown by bird species diversity (BSD). The oak woodland bird community was the most distinctive, whereas the pine-alder one was similar to the fir forests. Bird communities of the two pine forests had low si...
Se registran cuatro tipos de vegetación, representados por 10 comunidades vege- tales para el Mun... more Se registran cuatro tipos de vegetación, representados por 10 comunidades vege- tales para el Municipio de Guanaceví, Durango. Se reconocen cinco asociaciones vege- tales para los bosques de coníferas, 10 para bosques de Pinus-Quercus, nueve para bosques de Quercus-Pinus, cinco para bosques de Quercus y cuatro para el matorral de Arctostaphylos-Quercus. Se describen brevemente las comunidades vegetales que no fueron muestreadas como pastizal, vegetación riparia, vegetación acuática y semiacuá- tica y vegetación propia de sitios de disturbio y áreas agrícolas
SummaryIn this study I present data suggesting altitudinal movements of some species of foliage-g... more SummaryIn this study I present data suggesting altitudinal movements of some species of foliage-gleaning insectivorous birds and related species of an oak-pine woodland of western Mexico. These movements can be regarded as short-distance or local migrations because the species involved breed in the woodlands and forests of the Sierra Madre Occidental highlands and winter in the tropical forests of the Pacific lowlands. Nine species of insectivorous birds out of 17 breed at the study site in the mountains of southern Durango and move to the lowlands in the winter; these can be regarded as short-distance or local migrants. In Mexico tropical deciduous and semi-deciduous forests are distributed mostly in the Pacific lowlands in the states of Sinaloa, Durango, Nayarit and Jalisco. Tropical forests of the Pacific lowlands are very important as wintering grounds for both North American and local west-Mexican migrants; however, there is only one protected area in western Mexico which to so...
The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened w... more The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened with extinction. Its distribution is reported in two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas, and consists of sub-alpine grassland that is located in shallow valleys or shallows. In our case, "El Bajío la Cantera" of approximately 55 hectares, is mostly used in rainfed agriculture, protected from livestock grazing with wire fences, which in turn represents protection for remnants of grassland where they are the birds. “El Bajío la Cantera" belongs to Ejido 12 de Mayo, Municipality of San Dimas, Durango, where 28 males were detected singing along a 500 meter transect. This finding represents the population of the healthiest Sierra Madre Sparrow...
The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened w... more The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened with extinction. Its distribution is reported in two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas, and consists of sub-alpine grassland that is located in shallow valleys or shallows. In our case, "El Bajío la Cantera" of approximately 55 hectares, is mostly used in rainfed agriculture, protected from livestock grazing with wire fences, which in turn represents protection for remnants of grassland where they are the birds. “El Bajío la Cantera" belongs to Ejido 12 de Mayo, Municipality of San Dimas, Durango, where 28 males were detected singing along a 500 meter transect. This finding represents the population of the healthiest Sierra Madre Sparrow...
ABSTRACT. The Sierra Madre Sparrow (Xenospiza baileyi), an endemic species of Mexico, is threaten... more ABSTRACT. The Sierra Madre Sparrow (Xenospiza baileyi), an endemic species of Mexico, is threatened with extinction. Its distribution has been recorded from two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas and consists of sub-alpine bunch grasslands located in shallow valleys with ravines running through. The new locality, "El Bajío la Cantera", covers approximately 55 hectares, it is used mostly for temporal agriculture and protected from livestock grazing by fencing with barb-wire, protecting the remaining grassland and their birds. “El Bajío la Cantera" is part of Ejido 12 de Mayo, Municipality of San Dimas, Durango, and during a survey we detected 28 singing males along a 500 meter transect. This new locality has the healthiest population of the Sierra Madre Sparrow currently known, so it would be of conservation interest to document its population trend over time. This information will help to evaluate and propose the establishment of a special protection area for the Sierra Madre Sparrow, involving all society sectors (scientific community, land owners, and local and state authorities) to protect this very specialized and highly fragmented habitat to increase and maintain population size.
RESUMEN. San Juan de Camarones es una Región Terrestre Prioritaria (RTP) reconocida por la CONAB... more RESUMEN. San Juan de Camarones es una Región Terrestre Prioritaria (RTP) reconocida por la CONABIO y ubicada en el Municipio de Santiago Papasquiaro, Durango, al oeste del estado de Durango. En este estudio se documentan 165 especies de aves entre los años de 1997 y 2000. Se colectaron un total de 78 ejemplares de aves de 37 especies pertenecientes a 17 familia, tanto en bosques mixtos de pino-encino como en bosques tropicales caducifolios. Además, se hicieron recorridos por la región para obtener un listado más completo de la avifauna, especialmente de aquellas especies difíciles de colectar. Se presentan tres nuevos registros para el estado de Durango: Nictyphrynus mcleodii, Vireo hypochryseus y Melozone kieneri. Palabras clave: Biodiversidad, listado de aves, Durango, Regiones Terrestres Prioritarias (RTP).
Temperate forests are distributed over very extensivo areas in North America but in tropical Midd... more Temperate forests are distributed over very extensivo areas in North America but in tropical Middle America are limited to montane zones, and at the present time these montane forests are threatened by man because of overpopulation. I studied the structure and use of foliage of bird communities in montane temperate forests of , the Valley of Mexico. In August and September of 1981 I censused bird communities in six temperate forest study areas one each in oak woodland and pine-alder forest, and two each in pine forest and firforest using the variable circular-plot method. Overall bird densities were greater in broad-leaved forests than in coniferous forests. Species richness was similar between broad-leaved and pine forests but generally lower in fir forests. A similar trend was shown by bird species diversity (BSD). The oak woodland bird community was the most distinctive, whereas the pine-alder one was similar to the fir forests. Bird communities of the two pine forests had low si...
Se registran cuatro tipos de vegetación, representados por 10 comunidades vege- tales para el Mun... more Se registran cuatro tipos de vegetación, representados por 10 comunidades vege- tales para el Municipio de Guanaceví, Durango. Se reconocen cinco asociaciones vege- tales para los bosques de coníferas, 10 para bosques de Pinus-Quercus, nueve para bosques de Quercus-Pinus, cinco para bosques de Quercus y cuatro para el matorral de Arctostaphylos-Quercus. Se describen brevemente las comunidades vegetales que no fueron muestreadas como pastizal, vegetación riparia, vegetación acuática y semiacuá- tica y vegetación propia de sitios de disturbio y áreas agrícolas
SummaryIn this study I present data suggesting altitudinal movements of some species of foliage-g... more SummaryIn this study I present data suggesting altitudinal movements of some species of foliage-gleaning insectivorous birds and related species of an oak-pine woodland of western Mexico. These movements can be regarded as short-distance or local migrations because the species involved breed in the woodlands and forests of the Sierra Madre Occidental highlands and winter in the tropical forests of the Pacific lowlands. Nine species of insectivorous birds out of 17 breed at the study site in the mountains of southern Durango and move to the lowlands in the winter; these can be regarded as short-distance or local migrants. In Mexico tropical deciduous and semi-deciduous forests are distributed mostly in the Pacific lowlands in the states of Sinaloa, Durango, Nayarit and Jalisco. Tropical forests of the Pacific lowlands are very important as wintering grounds for both North American and local west-Mexican migrants; however, there is only one protected area in western Mexico which to so...
The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened w... more The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened with extinction. Its distribution is reported in two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas, and consists of sub-alpine grassland that is located in shallow valleys or shallows. In our case, "El Bajío la Cantera" of approximately 55 hectares, is mostly used in rainfed agriculture, protected from livestock grazing with wire fences, which in turn represents protection for remnants of grassland where they are the birds. “El Bajío la Cantera" belongs to Ejido 12 de Mayo, Municipality of San Dimas, Durango, where 28 males were detected singing along a 500 meter transect. This finding represents the population of the healthiest Sierra Madre Sparrow...
The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened w... more The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened with extinction. Its distribution is reported in two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas, and consists of sub-alpine grassland that is located in shallow valleys or shallows. In our case, "El Bajío la Cantera" of approximately 55 hectares, is mostly used in rainfed agriculture, protected from livestock grazing with wire fences, which in turn represents protection for remnants of grassland where they are the birds. “El Bajío la Cantera" belongs to Ejido 12 de Mayo, Municipality of San Dimas, Durango, where 28 males were detected singing along a 500 meter transect. This finding represents the population of the healthiest Sierra Madre Sparrow...
ABSTRACT. The Sierra Madre Sparrow (Xenospiza baileyi), an endemic species of Mexico, is threaten... more ABSTRACT. The Sierra Madre Sparrow (Xenospiza baileyi), an endemic species of Mexico, is threatened with extinction. Its distribution has been recorded from two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas and consists of sub-alpine bunch grasslands located in shallow valleys with ravines running through. The new locality, "El Bajío la Cantera", covers approximately 55 hectares, it is used mostly for temporal agriculture and protected from livestock grazing by fencing with barb-wire, protecting the remaining grassland and their birds. “El Bajío la Cantera" is part of Ejido 12 de Mayo, Municipality of San Dimas, Durango, and during a survey we detected 28 singing males along a 500 meter transect. This new locality has the healthiest population of the Sierra Madre Sparrow currently known, so it would be of conservation interest to document its population trend over time. This information will help to evaluate and propose the establishment of a special protection area for the Sierra Madre Sparrow, involving all society sectors (scientific community, land owners, and local and state authorities) to protect this very specialized and highly fragmented habitat to increase and maintain population size.
RESUMEN. San Juan de Camarones es una Región Terrestre Prioritaria (RTP) reconocida por la CONAB... more RESUMEN. San Juan de Camarones es una Región Terrestre Prioritaria (RTP) reconocida por la CONABIO y ubicada en el Municipio de Santiago Papasquiaro, Durango, al oeste del estado de Durango. En este estudio se documentan 165 especies de aves entre los años de 1997 y 2000. Se colectaron un total de 78 ejemplares de aves de 37 especies pertenecientes a 17 familia, tanto en bosques mixtos de pino-encino como en bosques tropicales caducifolios. Además, se hicieron recorridos por la región para obtener un listado más completo de la avifauna, especialmente de aquellas especies difíciles de colectar. Se presentan tres nuevos registros para el estado de Durango: Nictyphrynus mcleodii, Vireo hypochryseus y Melozone kieneri. Palabras clave: Biodiversidad, listado de aves, Durango, Regiones Terrestres Prioritarias (RTP).
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Palabras clave: Biodiversidad, listado de aves, Durango, Regiones Terrestres Prioritarias (RTP).
Palabras clave: Biodiversidad, listado de aves, Durango, Regiones Terrestres Prioritarias (RTP).