Figure 1.

Mean (±1 s.e.) feeder visits per hour per bird for the first and last 4 h of data against time for control (blue diamonds) and fluoxetine-treated birds (red squares). Time is expressed relative to sunrise (a) and sunset (b) and so the 4 h period for which observations were taken depended upon the time when birds first fed in the morning and last fed at night. (Online version in colour.)