Table 3. Analysis of the effect of ectoparasite load manipulation (parasites) methionine supplementation (methionine) and interaction between these treatments on final body size of blue tit nestlings.

factor	body mass N = 373			tarsus length N = 373			wing length N = 376
	df	F	p	df	F	p	df	F	p
parasites	1, 39	2.18	0.15	1, 39	0.15	0.70	1, 38	0.56	0.50
methionine	1, 329	0.09	0.76	1, 330	0.01	0.94	1, 325	0.26	0.61
interaction	1, 329	1.28	0.26	1, 330	0.10	0.76	1, 325	0.57	0.45

Statistics of a linear mixed model with brood nested in parasite treatment fitted as a random effect; variance component, its standard error and percentage of variance explained by brood effect nested in the parasite treatment is shown. N equals the number of nestlings measured.