Aspectos de la Biología de Psarocolius decumanus y Turdus grayi en la Estación Agraria Cotové, Santa Fé de Antioquia, Colombia

Aspects of the biology of the crested oropendolas Psarocolius decumanus and the clay-coloured Thrush Turdus grayi at the Cotove Agrarian Station at the National University of Colombia were studied. The Station is located in the municipality of Santa Fe de Antioquia, geographic area of tropical dry forest. The Agrarian Station is operated with a silvopastoral system, which integrates the use of trees and pastures in livestock production, thus conserving habitats for wildlife species. Six field samplings were carried out between December 2009 and October 2010, every two months, in both dry and rainy periods. Records of the presence of the both species in the different habitats available were made. It became evident the role that forest fragments and silvopastoral systems accomplishes in favor of the conservation of the diversity of birds, and in particular of the crested oropendolas and the clay-coloured Thrush. Psarocolius decumanus and Turdus grayi used the Agrarian Station as a foraging site, predominate in forest edges. Both species are very susceptible to the loss and fragmentation of the natural forest and to the transformation of these ecosystems into lands dedicated to agriculture and livestock, mainly the crested oropendolas that did not register reproductive activity during the study. The other hand, for the clay-coloured Thrush Turdus grayi , reproductive activity in the months of April and June 2010 was observed.