Birds of Sierra de Vallejo, Nayarit, Mexico

Sierra de Vallejo, is considered a priority region for conservation, and is strongly affected by anthropogenic pressures. The inventory of birds are refers to studies in near areas. This study is a concrete contribution of the birds of the mountain chain and north of it. We considered bibliographic records and databases available on the web with records of ocurrence and specimens of scientific collections. Also we perform point counts in different localities inside the reserve. We observed a richness of 261 birds species, the family Tyrannidae is the best represented. Of the species recorded, 177 are permanent residents (31 are endemic and 15 are quasi-endemics to Mexico) and 73 are migratory; the remaining eleven records have other status. Also 43 species are in endangered categories. We include species that have not been recorded in the lists of the area and records of species expand their ranges at Nayarit. Due to the great diversity of birds observed, it is necesary to continue the research work about habitat use, abundance and monitoring, it will provides the basis for the conservation of birds of Sierra de Vallejo

Importance of a tropical tree (Dendropanax arboreus) for Neartic migrant birds in Mexico

"En sus sitios reproductivos diversas especies de aves migratorias se alimentan principalmente de insectos, sin embargo, durante su migración en los neotrópicos comen cantidades significantes de frutos. Este estudio a través del análisis y obtención de semillas de restos fecales, observaciones focales de forrajeo, tiempos de retención de semillas en el intestino y porcentajes de germinación de semillas después de pasar por el tracto digestivo, muestra la importancia como recurso alimenticio del árbol tropical Dendropanax arboreus para varias especies de aves migratorias neárticas. Los análisis de muestras fecales mostraron que el 81% de los individuos con excretas que contuvieron semillas de este árbol fueron especies migratorias, principalmente del Zorzal maculado (Hylocichla mustelina), el Maullador gris (Dumetella carolinensis) y el Zorzal de Swainson (Catharus ustulatus). Las observaciones focales, mostraron que el 72% y el 75% de las visitas y de los frutos consumidos respectivamente correspondieron al Maullador gris y al Zorzal maculado. No obstante, el Zorzal de Swainson resultó la especie que permanece más tiempo alimentándose de frutos de D. arboreus. Por otro lado, el Zorzal maculado presentó el mayor tiempo promedio de retención de semillas 56,9 ± 32 min, así como el mayor porcentaje de germinación, mientras que el Zorzal de Swainson presentó el menor tiempo de retención y el menor porcentaje de germinación. En Los Tuxtlas, México los árboles de D. arboreus, se encuentran tanto en zonas conservadas como en perturbadas, y sus frutos constituyen una fuente rica en lípidos para las aves migratorias, mismas que podrían potencialmente dispersar sus semillas a largas distancias, manteniendo con ello la estructura poblacional de este árbol.""Many migratory birds feed insects in their reproductive range while they consume many kinds of fruits during their migration to the Neotropics. We evaluated the importance of fruits of a tropical tree Dendropanax arboreus, as a resource for many species of Nearctic migrant birds. We analyzed fecal samples collected from migratory birds and quantified foraging observations. Also, we compared gutretention times and percentages of germination of seeds defecated by birds. The analyzed fecal samples showed that 81% of them contained seeds of this tree. These fecal samples correspond to migratory birds, mainly Wood Thrush (Hylocichla mustelina), Gray Catbird (Dumetella carolinensis), and Swainson’s Thrush (Catharus ustulatus). Observations showed that 72% and 75% of the visits to trees and of the fruits consumed respectively corresponded to Gray Catbird and Wood Thrush. Nevertheless, Swainson’s Thrush was the species that spent more time feeding on fruits of D. arboreus. On the other hand, Wood Thrush had an average retention time of 56.9 ± 32 min, and seeds that passed through the gut had the highest percentage of germination, while those of Swainson’s Thrush had the least gut-retention time and the smallest percentage of seed germination. In Los Tuxtlas, Mexico, D. arboreus is found in undisturbed and regenerating forests, and its fruits constitute a rich source in lipids for migratory birds. These birds that potentially disperse the seeds of D. arboreus at long distances throughout the landscape, may also maintain the population structure of this tree.

DIVERSIDAD DE AVES EN BOSQUES DE PINO-ENCINO DEL CENTRO DE GUERRERO, MÉXICO

We assessed bird species richness and their abundances at three sites with pine-oak forest under different development stages (mature forest, regenerating forest and shade coffee plantation) in central Guerrero, Mexico. We recorded a total of 117 species and 1,276 individuals; however, analysis of cumulative species curves indicates that it is possible to find more species in the region for a more complete list. There were significant differences in species diversity among the three sites. Species diversity was higher at the regenerating forest, middle in mature forest and lowest at shade coffee plantation. Higher similarity was between mature forest and regenerating forest. There were no significant differences among the feeding guilds at any site. The mid-stratum had the highest utilization at the three sites. In addition, there were significant differences among strata in regenerating forest in comparison with mature forest and shade coffee plantation.Se estimó la riqueza y abundancia de aves en tres sitios con bosque de pino-encino con diferentes condiciones de desarrollo (bosque maduro, bosque en regeneración y bosque con cafetal) en el centro del estado de Guerrero, México. Entre los tres sitios se registró un total de 117 especies y 1,276 individuos; sin embargo, análisis de curvas de acumulación muestran que es posible registrar más especies para complementar el listado. Se obtuvieron diferencias significativas en la diversidad de especies entre los tres sitios, la mayor diversidad se presentó en el bosque en regeneración, seguido del bosque maduro y por último el bosque con cafetal. La mayor similitud de especies se registró entre el bosque maduro y el bosque en regeneración. No existen diferencias significativas entre los gremios alimentarios de los tres sitios. El estrato medio del bosque fue el más utilizado por las aves en los tres sitios, existiendo diferencias significativas en el uso de los estratos de la vegetación por las aves del bosque en regeneración en comparación con el bosque maduro, así como con el bosque con cafetal

DIVERSIDAD DE AVES EN BOSQUES DE PINO-ENCINO DEL CENTRO DE GUERRERO, MÉXICO

We assessed bird species richness and their abundances at three sites with pine-oak forest under different development stages (mature forest, regenerating forest and shade coffee plantation) in central Guerrero, Mexico. We recorded a total of 117 species and 1,276 individuals; however, analysis of cumulative species curves indicates that it is possible to find more species in the region for a more complete list. There were significant differences in species diversity among the three sites. Species diversity was higher at the regenerating forest, middle in mature forest and lowest at shade coffee plantation. Higher similarity was between mature forest and regenerating forest. There were no significant differences among the feeding guilds at any site. The mid-stratum had the highest utilization at the three sites. In addition, there were significant differences among strata in regenerating forest in comparison with mature forest and shade coffee plantation.Se estimó la riqueza y abundancia de aves en tres sitios con bosque de pino-encino con diferentes condiciones de desarrollo (bosque maduro, bosque en regeneración y bosque con cafetal) en el centro del estado de Guerrero, México. Entre los tres sitios se registró un total de 117 especies y 1,276 individuos; sin embargo, análisis de curvas de acumulación muestran que es posible registrar más especies para complementar el listado. Se obtuvieron diferencias significativas en la diversidad de especies entre los tres sitios, la mayor diversidad se presentó en el bosque en regeneración, seguido del bosque maduro y por último el bosque con cafetal. La mayor similitud de especies se registró entre el bosque maduro y el bosque en regeneración. No existen diferencias significativas entre los gremios alimentarios de los tres sitios. El estrato medio del bosque fue el más utilizado por las aves en los tres sitios, existiendo diferencias significativas en el uso de los estratos de la vegetación por las aves del bosque en regeneración en comparación con el bosque maduro, así como con el bosque con cafetal

Speciation in the Emerald Toucanet (*Aulacorhynchus prasinus*) complex

We analyzed genetic variation in the Emerald Toucanet (Aulacorhynchus prasinus), a species complex that ranges primarily along the montane forests of southern and eastern Mexico south to Bolivia. Segments of three mitochondrial DNA genes (cytochrome b, ND2, and ND3) were sequenced for a total of 1,159 base pairs. Using maximum parsimony, maximum likelihood, and Bayesian analysis,we found a set of seven differentiated populations that correspond to clear geographic breaks throughout the highlands of the Neotropics. These genetically distinct populations also correspond with the geographic breaks found in previous analyses of morphological data. Molecular evidence suggests species treatment for four of the Central American clades and three South American clades. Received 19 June 2006, accepted 28 January 2007

Diet and seed dispersal in two species of tanagers (Habia) from two types of vegetation in Los Tuxtlas, Ceracruz, Mexico

Fecal samples from mist-netted birds were used to determine the diet of the Red-throated (Habia fuscicauda) and Red-crowned (H. rubica) ant-tanagers in secondary vegetation and rainforest. The diet of both species is comprised mainly of various fruit species (65.9% and 66.6%) with animal prey making up a minor proportion (24.1% and 21.2%). Both species are considered dietary generalists and opportunists. In Los Tuxtlas, their diets are remarkably similar. The two species occur with equal frequency in the two types of studied vegetation and disperse seeds of several species of plant pioneers. These seeds are of great importance in the formation of seed banks that permit the development of secondary vegetation and, in the long run, the regeneration of the rainforest