Day length affects feeding behaviour and food intake in adult male emus (Dromaius novaehollandiae)

1. In south-western Australia, male and female emus decrease their food intake when they start breeding in early winter and increase their intake during spring and summer when the breeding season and egg incubation are finished. 2. This annual feeding cycle seems to be under the influence of several environmental factors. Here, we tested the importance of photoperiod using male emus kept in light-controlled rooms with ad libitum access to food and water. 3. Long days increased food intake whereas short days decreased it. Emus fed only during the light hours. 4. Frequency of meals was similar under the 2-day lengths but meal duration was shorter when the emus were on short days than when they were on long days. Thus, day length seemed to affect appetite but not interest in food. 5. Further investigations are needed to test whether these changes in feeding behaviour are a direct consequence of day length or if they are secondary to photoperiod-driven changes in sexual activity.