Table 2. Results from the best-fit (lowest AICc) linear mixed-effects model testing the prediction that the advantage of large size in aggressive contests for resources declines with genetic distance among interacting bird species (n = 244 species pairs).

Fixed effects1	Estimate	SE	t	df	P
Intercept	1.17	0.10	11.91	238	<0.0001
Difference in mass2	0.84	0.17	4.91	238	<0.0001
Genetic distance	0.91	0.48	1.89	238	0.0598
Difference in mass2×Genetic distance	−2.46	0.84	−2.94	238	0.0036

¹ dependent = sqrt{ln[(wins by dominant species+1)/(wins by subordinate species+1)]}; taxonomic group included as a random effect.

² (mass of dominant species−mass of subordinate species)/(average mass of dominant and subordinate species).