Table 1.

Characteristics of males that predicted their rankings by females under UV+ and UV− conditions, shown separately for morphometric variables and plumage reflectance spectra

Morphometrics
Trait	UV+ ranking predictor		UV− ranking predictor
	Statistic	P	Statistic	P
Mass	F =  0.58	NS	F =  1.00	NS
Fat score	S =  2.33	NS	S =  1.39	NS
Length of tarsus	F =  0.27	NS	F =  1.12	NS
Length of 8th primary	F =  2.75	NS	F =  0.11	NS
Asymmetry of tarsus	S =  0.28	NS	S =  1.88	NS
Asymmetry of 8th primary	K-W H =  3.15	NS	K-W H =  1.19	NS
Throat feathers with white tips, %	S =  3.12	NS	S =  4.86	NS
Covert feathers with white tips, %	S =  3.67	NS	S =  3.67	NS
Bill black, %	S =  0.19	NS	S =  0.10	NS

Spectrophotometrics
Trait	UV+ ranking predictor						Summary
	Wilk’s λ	P	mean	PC1	PC2	PC3
Throat	0.308	<0.05	1.08	1.62	7.58‡	0.60	preferred males have high “violet” and  “red” relative to UV and “green”
Throat tips	0.071	<0.01	2.72	4.03*	0.22	5.48†	preferred males “whiter”
Coverts	0.430	NS	3.92*	1.15	0.79	0.80	NS
Covert tips	0.616	NS	0.40	0.58	2.47	—	NS
	UV− ranking predictor
Throat	0.331	NS	0.81	1.83	1.30	0.53	NS
Throat tips	0.512	NS	0.68	1.11	0.55	0.79	NS
Coverts	0.725	NS	0.28	0.59	0.35	0.97	NS
Covert tips	0.585	NS	0.10	0.07	2.31	—	NS

Throat and coverts refer to the main iridescent region of the throat and wing covert feathers, respectively; tips are their white/brown margins. In all cases, the independent variable is rank, with four levels (1 = most preferred, 4 = least preferred). Morphometrics: Variables are compared by univariate tests. S refers to Friedman’s nonparametric repeated-measures ANOVA (15), with the males’ quartet as the blocking factor. Because primary feather asymmetry had too many missing values (due to abrasion of tips) for Friedman’s test, Kruskal–Wallis’ nonparametric ANOVA was used (15) as if males were independent. For repeated-measures ANOVA F tests, df = 3,21; for Friedman S and Kruskal–Wallis H, df = 3. Spectrophotometrics: Plumage variables are compared by repeated-measures MANOVA and ANOVA with 10 replicate feathers per region per bird (measurement details in legend of Fig. 3). For the UV+ rankings, mean reflectance and principal components (PC) are calculated from the full avian visible range (300-700 nm); for the UV− rankings, they are calculated for the human visible range (400-700 nm). Principal components were calculated from standardized reflectance measurements (mean reflectance subtracted) such that PC1 is the first component of spectral shape rather than a correlate of mean reflectance. Only PCs explaining >5% of the spectral variation are included. Wilk’s λ tests the mean reflectance and main PCs together by repeated-measures MANOVA, with ∗, P < 0.05;  

^†, P < 0.01; and  

^‡, P < 0.001. Only where Wilk’s λ is significant should the univariate F tests for each dependent variable be consulted; for Wilk’s λ, df = 12,47.