Fig. 5. Example of oxygen measurement during song by a starling in the small respirometry chamber illustrating the difference in the rate of oxygen consumption (_O2) between soft and loud song. Song is illustrated as an oscillogram (bottom panel), and two segments (horizontal grey bar) are also shown spectrographically (top panel). Note the more rapid response of the oxygen measurements (vertical line) than in the large respirometry chamber (see Fig. 4), as exemplified at the onset of the loud portion of song.