Fig. 3. The mask system provided enough temporal resolution to see small oscillations in oxygen consumption rate (_O2) that corresponded to individual breath cycles, measured as air sac pressure (P). The horizontal line represents ambient pressure; air sac pressure above and below the line correspond to expiration and inspiration, respectively. Respiratory changes caused by defecation, presentation of the female and song have rapid responses in the oxygen consumption of the bird. Defecation (marked by first arrow) has a distinct pressurization in the air sacs with simultaneous closure of the airways (airflow data are not displayed). It is accompanied by a pronounced decrease in oxygen consumption. Note that the defecation event is followed by two calls (substantially higher pressure peaks). Elevated respiratory rate caused by female presentation (second arrow) is accompanied by increased oxygen consumption, as is subsequent song (third arrow marks the first of two song bouts).

Return to article