Table 1. General linear models of flight performance traits of barn swallows (aerial manoeuvrability, maximum acceleration and maximum velocity) as a function of numbers of feather holes, with sex and morphological traits as covariables. Time to copy the flight maze was used as a measure of aerial manoeuvrability, with a shorter flight time indicating grater manoeuvrability. The number of feather holes in tail feathers was not significantly related to flight performance traits and consequently is not shown in the table.

Effects	Time to copy the flight maze		Acceleration		Velocity
	SS	Test statistics (slope, 95% CI)	SS	Test statistics (slope, 95% CI)	SS	Test statistics (slope, 95% CI)
Constant	0.028		8.216		0.012
Wing feather holes			13.501	F1,91 = 4.82* (−0.208, −0.397 to −0.019)	4.412	F1,95 = 9.18** (−0.283, −0.468 to −0.097)
Wing feather holes × sex			14.563	F1,91 = 5.19* (0.328, 0.042 to 0.614)
Sex			1.395	F1,91 = 0.50 (−0.108, −0.411 to 0.196)
Wing area					2.233	F1,95 = 4.65* (0.203, 0.016 to 0.389)
Aspect ratio	0.793	F1,132 = 5.95* (0.207, 0.039 to 0.375)	21.514	F1,91 = 7.67** (−0.276, −0.473 to −0.078)
Keel			11.389	F1,91 = 4.06* (0.204, 0.003 to 0.406)	2.212	F1,95 = 4.60* (0.202, 0.015 to 0.389)
Tail length	0.802	F1,132 = 6.01* (−0.208, −0.376 to −0.040)
Model statistics	$R_{\mathrm{adj}.}^2$ = 0.06, F2, 132 = 5.14**		$R_{\mathrm{adj}.}^2$ = 0.17, F5,91 = 4.81***		$R_{\mathrm{adj}.}^2$ = 0.15, F3, 95 = 6.75***

SS – sums of squares; *p < 0.05, **p < 0.01, ***p < 0.001, blank – not significant.