Here, we assess seed preferences in four species of sparrows that are common to the central
Monte desert of Argentina. Our hypotheses are
that (1) sparrows always prefer seeds of grasses
over forbes for feeding and (2) different species of sparrows show the same preferences
when consuming seeds. To detect seed species
that are preferred, avoided, or less preferred
(those seeds that are only consumed when the
preferred seeds are not available), we used
experiments that combined choice and nonchoice trials (Cueto et al. 2001). This approach
allows us to distinguish among those categories
of seed preferences, infer plausible mechanisms
involved in seed preferences, and assess their
consequences on plant–animal interactions.