Short- and long-distance avian migrants differ in exercise endurance but not aerobic capacity

BMC Zoology

Table 2 Summary statistics of linear regression models testing for differences in aerobic capacity estimates

Aerobic capacity	Resting metabolic rate (RMR_min)		Maximal metabolic rate (MMR)		Time to exhaustion
Aerobic capacity	t	p	t	p	t	p
Intercept	−39.85	< 0.001	−14.95	< 0.001	−0.36	0.72
migration strategy	0.15	0.88	−0.14	0.88	−3.32	0.001*
w/i SD	4.27	< 0.001*	2.02	0.05*	−0.08	0.93
w/i LD	−3.26	0.001*	1.69	0.09	−1.50	0.14
sex	2.78	0.006*	−0.43	0.67	−2.16	0.03*
infection	0.01	0.99	2.47	0.01*	1.07	0.28
haemoglobin	−0.24	0.81	2.87	0.004*	3.07	0.002*
F (df)	6.54 (6176)	< 0.001*	2.97 (6240)	0.008*	7.15 (6241)	< 0.001*

Legend: Aerobic capacity estimates are the mass-specific resting and maximal metabolic rates (oxygen consumption rates, ml g⁻¹ min⁻¹), and the endurance exercise given as time to exhaustion (min). Migration strategy provides the comparison between long-distance (LD) and short-distance migration (SD), whereas w/i SD and w/i LD give the comparison between species within each migration strategy. Factors sex, infection, and the covariate haemoglobin test for differences between males and females, between non-infected and haemosporidian-infected birds as well as for the potential dependency with total haemoglobin in peripheral blood. F, df, t and p-values are the accompanying statistical model parameters, * indicates statistically significant differences at p ≤ 0.05 (for details see Methods)

ISSN: 2056-3132