Respiration,oxygen consumption and heart rate in some birds during rest and flight

Summary Pulmonary ventilation (tidal volume, frequency) and oxygen content of expired air were measured in separate flights for 3 species of birds — Evening Grosbeak (Hesperiphona vespertina), Ring-billed Gull (Larus delawarensis), and Black Duck (Anas rubripes). Heart rate was measured in flight or immediately after landing in 12 species.Respiratory frequency and tidal volume were greater in flight than during rest. As the O₂ content of expired air did not change appreciably, the increase in O₂ consumption was similar to the increase in ventilation and averaged more than 10 times basal. The influence of body weight on metabolism during flight was similar to that previously observed under basal conditions.Heart rates during flight (10 species), immediately after landing (12 species), and maximal rates from various authors (15 species) were in close agreement, and were 2–4 times as high as during rest. The heart rate decreased with increasing body weight according to the equation HR_f=25.1 BW^–0.16 (HR per sec, BW in g). In flight there was much less variation and there was a smaller decrease with increasing weight than during rest. Although the estimated stroke volume and heart size appear larger in birds, the ratio of these functions was similar to that in mammals.Issued as N.R.C.C. No. 11094.The valuable technical assistance of Mr. B. Mackenzie and Mr. R. Charbonneau made this study possible. We are also indebted to Dr. Doris Jensen of McMaster University for providing facilities for tests on ring-billed gulls.