Fig. 2

Variation in daily total song output (average number of songs per day per individual) of male Savannah Sparrows with respect to time of year (a) and breeding stage (b). Output was highest in early spring and declined to low levels by late summer. Whiskers show standard error around the mean total song output, per day, per individual for n = 34 males recorded from late April until late August on Kent Island, New Brunswick, Canada. May begins on ordinal day 121; June on ordinal day 152; July on ordinal day 182; and August on ordinal day 213. Birds were recorded approximately every 14 days across the season; data are organized into 10-days bins in the top panel