Table 3. Effects of specific recognition cues on great reed warbler aggression near the nest.

Minimal adequate model	df	F	p
Eyes	1, 51.81	181.98	<0.0001
Underparts	1, 87.16	9.65	0.003

Yellow eye colour and barred underparts (typical for natural cuckoos) were either present or absent on a particular dummy (Fig. 1). Statistics are from GLMM models with Box-Cox transformed response, for effect sizes see Fig. 3.