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Table 1 Results of analyses on early and late nestling growth, fledgling body mass and tarsus length

From: The effect of pre-laying maternal immunization on offspring growth and immunity differs across experimentally altered postnatal rearing conditions in a wild songbird

Sources of variation df F P
Early nestling growth (g per day); N = 352
 Year 1, 51.28 9.74 0.003
 Maternal immunization 1, 21.43 0.09 0.767
 Brood size manipulation 1, 46.48 0.93 0.339
 Nestling status 2, 83.99 0.12 0.888
 Offspring sex 1, 300.93 6.80 0.010
 Hatching date 1, 50.68 5.33 0.025
 Hatchling body mass 1, 302.87 488.34 <  0.001
Square-transformed late nestling growth (g per day); N = 281
 Year 1, 37.99 0.06 0.805
 Maternal immunization 1, 22.13 0.80 0.381
 Brood size manipulation 1, 34.93 11.96 0.001
 Nestling status 2, 73.25 0.75 0.474
 Offspring sex 1, 244.12 28.12 <  0.001
 Hatchling body mass 1, 247.91 339.78 <  0.001
 Maternal immunization × brood size manipulation 1, 230.37 7.47 0.007
Fledgling body mass (g); N = 281
 Year 1, 36.13 3.84 0.058
 Maternal immunization 1, 20.71 0.55 0.468
 Brood size manipulation 1, 39.20 18.96 <  0.001
 Nestling status 2, 66.04 0.54 0.586
 Offspring sex 1, 233.14 50.85 <  0.001
 Hatchling body mass 1, 242.28 26.94 <  0.001
 Maternal immunization × brood size manipulation 1, 226.81 7.78 0.006
 Maternal immunization × offspring sex 1, 230.44 2.99 0.085
Fledgling tarsus length (mm); N = 281
 Year 1, 30.46 0.04 0.842
 Maternal immunization 1, 35.73 2.86 0.099
 Brood size manipulation 1, 32.31 1.84 0.184
 Nestling status 2, 78.58 0.64 0.530
 Offspring sex 1, 259.34 33.00 <  0.001
 Hatchling body mass 1, 263.82 6.21 0.013
 Maternal immunization × brood size manipulation 1, 232.86 5.83 0.017
  1. Table 1 presents the results of linear mixed models that examined the effects of a set of explanatory variables on early nestling growth, square-transformed late nestling growth, fledgling body mass and fledgling tarsus length. Full models included year (to control for inter-season differences), maternal immunization (control vs. immunized females), brood size manipulation (control vs. enlarged broods), nestling status (to control for cross-fostering effects; there were three levels of this factor: nestlings from cross-fostered nests moved to foster broods, nestlings from cross-fostered nests that stayed in their original broods and nestlings from non-cross-fostered nests where all nestlings stayed in their original nests) and offspring sex (to control for differences between male and female nestlings) as fixed factors, and hatching date, clutch size and hatchling body mass (2 days after hatching) as covariates. All two-way interaction terms between maternal immunization, brood size manipulation and offspring sex were tested as well. Nest of origin (female identity) and nest of rearing (foster female identity) were included in all models as random factors (results not shown). Presented are reduced models after sequential backward elimination of non-significant (if P ≥ 0.10) interactions and covariates