Synergistic effects of food and predators onannual reproductive success in song sparrows

The behaviour literature is full of studies showing that animals in every taxon balance the probability ofacquiring food with the risk of being preyed upon. While interactions between food and predators clearlyoperate at an individual scale, population-scale studies have tended to focus on only one factor at a time.

Liana Zanette et al, Proc. R. Soc. Lond. B (2003) 270, 799-803, 2003