Table 2.

The effects of estimated fuel load (energy stores), subspecies, time of capture, and sex on Northern wheatears’ malondialdehyde level (MDA), and total non-enzymatic antioxidant capacity (AOX) in models without and with uric acid concentration (UA) level as a covariate. Variable statistics are given as in the step prior to removal from the model. The final models are in italic.

	β ± SE	t	P	df
MDA model (n = 39)
Fuel load	−2.255 ± 0.534	−4.43	<0.001	1
Subspecies	−0.236 ± 0.108	−2.19	0.035	1
Time of capture	−0.052 ± 0.407	−0.13	0.90	1
Sex	−0.236 ± 0.112	−2.11	0.042	1
AOX model without UA (n = 63)
Fuel load	0.147 ± 0.237	0.62	0.54	1
Subspecies	0.030 ± 0.044	0.69	0.50	1
Time of capture	0.334 ± 0.159	2.10	0.040	1
Sex	0.054 ± 0.043	1.25	0.22	1
AOX model with UA (n = 59)
Fuel load	−0.083 ± 0.195	−0.43	0.67	1
Subspecies	−0.006 ± 0.038	−0.15	0.88	1
Time of capture	0.178 ± 0.137	1.30	0.20	1
Sex	−0.013 ± 0.038	−0.36	0.72	1
UA concentration	0.003 ± 0.001	6.0	<0.001	1

Reference categories were oenanthe for subspecies and male for sex.