The Grey-backed Shrike parents adopt brood survival strategy in both the egg and nestling phases

Table 1 Factors that might influence the egg’s fresh mass in the Grey-backed Shrike

Generalized linear mixed model parameters
Fixed effects	β ± SE	n	t	P
Intercept	4.274 ± 0.094	151	45.618	< 0.001
Clutch initiation date	– 0.002 ± 0.003	151	– 0.555	0.580
Laying sequence	0.058 ± 0.016	151	3.697	< 0.001

Random effects	β ± SD	n	Results of VCA (%)
Nest identity	0.097 ± 0.311	151	66.90
Years	0.001 ± 0.001	151	0.69
Residual	0.047 ± 0.217	151	32.41

SE of fixed effects is the standard error of the mean; SD of random effects is the square root of the variance. The explanations apply also to Table 2, 3 and 4