Bird that fed stay: food availability as a bird community structurer in central Argentina

Food availability plays a key role in the environmental usage by animals. Year round fluctuations on food resources are a fact among temperate and subtropical regions. In central Argentina winter is characterzied by a decrease in the availability of fleshy-fruits. However at the same time some alien species fruit in that period of scarcity. The objective of this work was to test the effect of fruit availability of fleshy-fruited alien plants on the community of birds of Traslasierras Valley of Cordoba, Argentina. We conduced bird point counts in three invaded and three non-invaded sites in five periods during the year. We estimate three Hill numbers (Shannon, Simpson and Evenness) and we compare that as a function of condition and period. We found that there is an effect of the interaction between factors for each hill number (H’, p<0.0001 ; D, p=0.0001; Evenness, p=0.01). In the evenness index we found a remarkable decrease that could suggest that a bottom-up effect of fleshy fruited alien plants is taking place the studied bird community.