Food availability but not cold ambient temperature affects undirected singing in adult male zebra finches.

Adult male zebra finches (Taeniopygia guttata) produce hundreds of song bouts per day, even when housed in social isolation. Whether the production of this "undirected song" is influenced by specific environmental factors is unclear, although we previously found that short-term food (but not water) deprivation leads to a prompt cessation of singing. Here, male zebra finches were placed on a schedule of restricted feeding for 11 days to ask whether stimulus features associated with food influenced undirected song independent of the effect of food on body mass. We also evaluated the within-day effects of ambient temperature (Ta) variation on metabolic rate and then, based on these data, placed male zebra finches on 5 days of cold Ta (8 degrees C) to determine whether a moderately increased energy demand associated with cold Ta would influence undirected song. Daily song production and several energetic variables were measured during each manipulation, and data obtained during baseline and recovery periods (food and water available ad libitum, Ta=26 degrees C) provided a standard for comparison. Our results showed that the schedule of restricted feeding produced more than two-thirds reduction in the daily production of undirected song, while cold Ta had no effect. Daily food intake and body mass were well defended under both manipulations. Thus, undirected singing by adult male zebra finches appears to show a specific relationship to the availability of food. Possible mechanisms linking food availability to singing are discussed.