Table 2. Linear mixed models describing the surface temperature of the bill (T_bill).

Models	K	AICc	ΔAICc	AICc weight
SSP + Ta	6	861.232	0	0.208
SSP + Ta + Ta 2	7	861.571	0.339	0.176
SSP * Ta	7	861.730	0.498	0.162
Ta	5	862.071	0.839	0.137
Ta + Ta 2	6	862.371	1.139	0.118
SSP + Ta + Ta 2 + Ta 3	8	863.079	1.847	0.083
Ta + Ta 2 + Ta 3	7	863.884	2.652	0.055
SSP * Ta + SSP * Ta 2	9	864.018	2.786	0.052

Individual is a random effect and square root of activity is a fixed effect in each model. SSP = subspecies, T_a = ambient temperature. Models with ΔAICc <5 are included here (see full model set in Table S1).