Table 2.

Commonly used proxies for quality to evaluate the relationship between carotenoid-based feather coloration and individual quality

Category	Metric	Relationship with quality
Condition	Body mass	+
	Size-adjusted body mass	+
	Ptilochronology	+
Immune and oxidative physiology	Anti-oxidant capacity	+
	Antibody count	+
	Disease survival	+
	Environmental pollutant	−
	HL ratio	−
	Pathogen challenge	−
	Oxidative damage	−
	PHA response	+
	WBC count	+
Parasite	Load	−
	Resistance	+
Parental and reproductive quality	Clutch size	+
	Feeding rate	+
	Fledgling number	+
	Fledgling success	+
	Lay date	−
	Nest attentiveness	+

+ indicates that this measure has a positive correlation with individual quality.− indicates that this measure has a negative correlation with individual quality