944 resultados para Northern leopard frog


Relevância:

20.00% 20.00%

Publicador:

Resumo:

En este relato nigeriano se cuenta la amistad que, en medio de la selva, hacen una rana llamada Niporbite y una serpiente llamada Clawsangnaws.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Guía geológica con catorce excursiones de fácil acceso para conocer la amplia variedad de rocas y estructuras existente en la zona de Moine Supergroup. Contiene mapas geológicos de cada ruta y datos sobre el itinerario de cada excursión, así como datos adicionales (tipo de terreno, distancia y tiempo). La guía ha sido escrita por aquellos que tienen algún conocimiento previo de geología, por ejemplo, estudiantes graduados y geólogos profesionales. También se menciona que es necesario llevar calzado, ropa de abrigo e impermeable para realizar estas curiosas rutas.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Populations on the periphery of a species' range may experience more severe environmental conditions relative to populations closer to the core of the range. As a consequence, peripheral populations may have lower reproductive success or survival, which may affect their persistence. In this study, we examined the influence of environmental conditions on breeding biology and nest survival in a threatened population of Loggerhead Shrikes (Lanius ludovicianus) at the northern limit of the range in southeastern Alberta, Canada, and compared our estimates with those from shrike populations elsewhere in the range. Over the 2-year study in 1992–1993, clutch sizes averaged 6.4 eggs, and most nests were initiated between mid-May and mid-June. Rate of renesting following initial nest failure was 19%, and there were no known cases of double-brooding. Compared with southern populations, rate of renesting was lower and clutch sizes tended to be larger, whereas the length of the nestling and hatchling periods appeared to be similar. Most nest failures were directly associated with nest predators, but weather had a greater direct effect in 1993. Nest survival models indicated higher daily nest survival during warmer temperatures and lower precipitation, which may include direct effects of weather on nestlings as well as indirect effects on predator behavior or food abundance. Daily nest survival varied over the nesting cycle in a curvilinear pattern, with a slight increase through laying, approximately constant survival through incubation, and a decline through the nestling period. Partial brood loss during the nestling stage was high, particularly in 1993, when conditions were cool and wet. Overall, the lower likelihood of renesting, lower nest survival, and higher partial brood loss appeared to depress reproductive output in this population relative to those elsewhere in the range, and may have increased susceptibility to population declines.