Table 2.

Female comb size as a signal of fecundity: statistical analysis of the difference in (a) body mass, (b) egg mass and (c) yolk mass between females with relatively large and small combs and (d) the changes in female comb size across stages of incubation. (Significant values are shown in boldface type.)

analysis	term	parameter	effect ±s.e.		d.f.	F	p
(a) body mass	comb rank	large	46.74	27.38	1, 16	8.06	0.006
small	−34.90	26.55
body size difference		6.82	1.68	1, 16	16.55	0.0009
(b) egg mass	comb rank	large	1.01	0.55	1, 17	13.96	0.002
small	−1.25	0.53
body mass difference		0.008	0.004	1, 15	4.33	0.055
body size difference	—		—	1, 15	3.05	0.10
(c) yolk mass	comb rank	—		—	1, 15	2.21	0.16
body mass difference		0.002	0.001	1, 16	4.89	0.04
body size difference	—		—	1, 14	0.37	0.56
egg mass difference		0.22	0.07	1, 16	11.87	0.004
(d) stage of incubation	stage of incubation	before	295.28	20.39	3, 50	4.34	0.009
start	289.34	23.70
incubating	251.34	20.36
after	269.58	20.84
body mass		0.48	0.09	1, 50	29.87	<0.0001
body size	—		—	1, 50	0.01	0.91