Fig. 4. (A) Oxygen consumption rate increased during stepwise hypoxia in bar-headed geese (light grey triangles), greylag geese (black squares) and pekin ducks (dark grey circles). Bar-headed geese had higher oxygen consumption rates than both other species during 7% inspired O₂ (asterisks). Differences between species persisted after mean oxygen consumption rates were corrected for differences in body temperature depression (see Materials and methods), using Q₁₀ values of either 2 (short broken lines) or 3 (long broken lines). (B) Oxygen consumption rates decreased rapidly during normoxic recovery in all species.