Skip to main content

Table 2 Summary of linear mixed models of egg shape (sphericity) of blue tits in relation to year, site, clutch size and egg volume. Two separate models are shown: (i) with year as a categorical variable and (ii) with year as a continuous variable. Clutch ID included as a random effect

From: A consistent long-lasting pattern of spatial variation in egg size and shape in blue tits (Cyanistes caeruleus)

Effect b-Estimate ± SE df F P
Year as a categorical variable
 Final model
  Intercept 76.54 ± 1.03 1;1698.2 9859.9 <  0.0001
  Year Multiple estimates 11;764.9 1.5 0.118
  Site 3.49 ± 0.96 1;8067.3 13.2 <  0.0001
  Clutch size 0.014 ± 0.055 1;785.0 0.7 0.796
  Egg volume −0.68 ± 0.14 1;8484.1 21.6 <  0.0001
  Site x Egg volume −2.37 ± 0.81 1;8483.2 8.7 0.003
 Deleted terms
  Site x Clutch size   1;757.4 0.001 0.999
  Egg volume x Clutch size   1;8408.8 0.008 0.928
  Year x Site   11;762.6 0.6 0.837
  Year x Clutch size   11;771.9 0.9 0.562
  Year x Egg volume   11;8299.4 1.2 0.284
Year as a continuous variable
 Final model
  Intercept 119.9 ± 65.0 1;775.6 3.5 0.061
  Year −0.021 ± 0.032 1;775.1 0.4 0.503
  Site 3.57 ± 0.95 1;8113.6 13.9 <  0.0001
  Clutch size 0.034 ± 0.053 1;795.1 0.404 0.525
  Egg volume −0.68 ± 0.13 1;8498.7 21.8 <  0.0001
  Site x Egg volume −2.41 ± 0.81 1;8495.3 8.9 0.003
 Deleted terms
  Site x Clutch size   1;788.3 0.2 0.901
  Year x Site   1;794.5 0.2 0.681
  Egg volume x Clutch size   1;8374.0 0.695 0.405
  Year x Egg volume   1;8455.2 1.9 0.163
  Year x Clutch size   1;793.1 3.4 0.063
  1. Bold entries highlight statistically significant effects, P < 0.05