Birds Project

As part of the general project, aimed at analyzing the reciprocal effects of seeds and their consumers and the possible consequences of those effects on plant population dynamics, our research is focused on the relationships between birds and seeds. We evaluate the potential impact of birds on soil seed reserves (top-down approach), as well as the effects of the seed availability on bird ecology (bottom-up approach). Until a few years ago, the role of birds as seed consumers had been under little concern. This is evident when we consider the scarcity of field and laboratory studies on birds compared to similar studies on rodents and ants. This bias on animal-plant relationship studies may have affected the explanatory and predictive capacity of numerous studies on desert community ecology.

Although there is a solid knowledge of the natural history of some granivorous birds in South America, their ecological role in different ecosystems is not completely clear. There is growing evidence in arid zones (central and southern Monte, northern and central Chilean matorral) showing hat these animals are the main seed consumers during certain seasons or all year round. This constitutes the first condition to suspect that birds may have an important role in the conformation of arid communities (through either direct or indirect effects). On the other hand, preliminary information also indicates that previous rainfalls or the level of seed reserves trigger numerical and functional responses in the northern and central Monte. Thus, the background information shows that understanding the ecology of granivorous birds can constitute a substantial element to explain and predict the dynamics of birds, seeds and plants in South American deserts. The questions leading our investigations are: (1) whether these populations are limited by food obtention, (2) whether there are adaptative processes in the seed–birds relationship, and (3) whether this relationship could constitute a structuring force for the Monte desert communities.

For some years (especially since 1993), we have been studying the granivorous birds-seeds system to answer those questions. A brief summary of the past research lines can be found at Research done. We are currently developing three research lines: Feeding preferences, Use of space (for feeding) and Movements.