Table 1 Three top-weighted models explaining median T _air values in panting/gular flutter behaviour (pant ₅₀) using both generalized linear models (GLS) and phylogenetic independent analyses (PGLS). The global model included: log₁₀ body mass (log₁₀ M _b); proportion of observations where birds were mobile (prop_act), and exposed to full sun (prop_sun) at air temperature between 35 and 40 °C (see methods for details); drinking dependency; foraging location; and diet as independent variables. Only the variables that were influential in the three top-weighted models are shown. For each variable we provide the contrast (± standard error), and significance level (see note below Table)

log₁₀ M _b

−5.62 ± 1.56**

−5.06 ± 1.57**

−5.29 ± 1.56**

prop_act

−7.69 ± 1.91**

−7.79 ± 1.97**

−6.73 ± 2.02**

Drinking dependency (non-drinking)

3.12 ± 0.81**

2.94 ± 0.83**

3.12 ± 0.80**

Foraging location (terrestrial)

1.32 ± 0.79

1.54 ± 0.79

prop_sun

2.86 ± 2.20

Intercept

48.30 ± 3.15**

48.20 ± 3.26**

46.57 ± 3.38**

Observations

30

30

30

AICc

136.4

136.4

137.8

prop_act

−1.56 ± 2.20

Drinking dependency (non-drinking)

4.08 ± 1.06**

4.04 ± 1.15*

3.95 ± 1.09*

prop_sun

5.07 ± 2.42

−4.59 ± 2.55

Intercept

34.44 ± 2.72**

36.07 ± 4.04**

35.05 ± 2.88**

Observations

30

30

30

AICc

159.7

161.7

161.8