Figure 1.

During acute heat exposure, the body temperature of red-billed queleas (Quelea quelea, red circles, lower panel) remained largely within the range reported in other passerine birds at air temperatures below 45 °C but increased well above previously-documented values at higher air temperatures. The grey band is the range of individual values in five Australian species⁴⁰ and three southern African species²⁷ in studies using the same experimental protocol. The dashed line indicates equality between air and body temperatures. The ratio of evaporative heat loss (EHL) to metabolic heat production (MHP) increased to an average maximum value of 1.49 at air temperatures above 46.9 °C (upper panel).