Differential changes in the morphology and fuel loads of obligatory and partial migrant passerines over half a century in Britain

Table 3 The results of linear regression of lean body mass (M_b-lean, Eq. 1) against year by species, including changes (∆) between 1964 and 2020 and mean M_b-lean for those which showed no significant change

Species	Gradient (m)	Intercept (b)	Adjusted R²	Standard error of residuals	F	P	Mean M_b−lean (g)	Δ M_b−lean (%)
*A. pratensis*	0.004	6.42	0.00	0.70	3.04	0.82	15.38	1.65
*E. rubecula*	0.001	13.60	< 0.01	0.34	0.58	0.45	14.88	0.24
*O. oenanthe*	0.058	-92.27	0.32	1.48	22.94	< 0.01		15.01
*P. collybita*	0.001	5.82	< 0.01	0.33	0.22	0.64	6.83	0.41
P. modularis*	0.007	3.78	0.05	1.06	42.21	< 0.01		2.25
*P. phoenicurus*	-0.001	15.07	0.01	0.19	1.69	0.20	13.10	-0.42
*P. trochilus*	0.004	-0.19	0.02	0.45	34.14	< 0.01		2.89
S. atricapilla*	0.002	11.90	0.02	0.64	28.17	< 0.01		0.79
S. borin*	< 0.001	16.20	< 0.01	0.37	0.35	0.55	16.53	0.12
C. communis*	0.003	7.68	0.09	0.50	189.3	< 0.01		1.14
*S. vulgaris*	0.036	4.77	0.06	2.10	8.61	< 0.01		2.67
*T. iliacus*	0.016	23.57	0.01	1.92	11.42	< 0.01		1.63
T. merula*	0.005	77.79	< 0.01	2.13	5.64	< 0.05		0.34
T. philomelos*	0.019	25.20	0.07	1.54	40.02	< 0.01		1.68
*T. troglodytes*	0.002	5.29	< 0.01	0.33	3.37	0.07	8.51	1.07

* Species where regressions were conducted using robust standard errors due to heteroscedasticity

ISSN: 2051-3933