Aerial view of one vineyard site illustrating: (A) experimental treatment; (B) no nest box control; (C) wooded riparian zone; (D) surrounding vineyards; and (E) oak savannas.

<p>Within nest box treatment (A), each star indicates one pair of nest boxes mounted back-to-back 85 m from each other.</p

Mean (± SE) avian species richness observed or heard over the 30-minute observations and average avian abundance per 5-minute observation interval for nest box treatments and control areas.

<p>Treatment means and standard errors were calculated from both sites over early, middle, and late time periods. Estimated <i>P</i>-values are from bootstrap resampling (see methods).</p