Sparrows Affected by Sound of Predators

A study has shown that song sparrows, even when protected from attack, raised 40% fewer offspring when subjected to recordings of predators calling and approaching. The study was done in an attempt to understand the indirect effect of predators on the lives of their prey. Ecologist Liana Zanette explains, "Predators shape everything. Wolves that eat elk give more plants a chance to survive, which in turn changes which other creatures thrive."

http://www.sciencenews.org/view/generic/id/336823/title/Mere_fear_shrinks_bird_families