Difference in behaviors between males with and without nest boxes. Mean number of behaviors in nest box owners, in black boxes, and non-owners in white for (A) Song, (B) Nest box specific behaviors (looking in the nest box, entering the nest box, collecting nest material), and (C) measures of agonistic behavior (chasing and displacements of conspecific males). Asterisk indicates significant differences between nest box owners and non-owners (p < 0.05).