Skip to main content

Table 1 Baseline corticosterone (y1), “increase in corticosterone” (y2) and “stress-induced corticosterone” (y3) models selected from AICc analyses

From: Diurnal variation in corticosterone release among wild tropical forest birds

  Response Variable Linear Formula (Intercept and Variable Coefficients) ωi
Int. Time Date Molt Hemo. R. Mass Lat.
Total y1 +1.871 [+1.697, +2.046] −0.236 [−0.388, −0.086] --- −0.325 [−0.631, −0.016] ---   +0.296 [+0.150, +0.444] 0.29
y3 +4.130 [+3.976, +4.283] --- --- −0.310 [−0.575, −0.048] --- --- n/a 0.19
Males y1 +2.179 [+1.846, +2.514] −0.312 [−0.549, −0.075] +0.377 [+0.095, +0.646] −0.714 [−1.324, −0.104] --- --- +0.278 [+0.026, +0.525] 0.26
y2 +4.303 [+3.963, +4.640] --- +0.376 [+0.076, +0.676] −0.838 [−1.436, −0.259] --- --- --- 0.24
y3 +4.396 [+4.087, +4.716] --- +0.378 [+0.094, +0.665] −0.757 [−1.319, −0.208] --- --- n/a 0.36
Females y1 a +1.838 [+1.491, +2.198] −0.356 [−0.641, −0.064] --- −0.661 [−1.204, −0.108] --- --- --- 0.09
G. spirurus y1 +1.952 [+1.591, +2.312] −0.667 [−1.110, −0.219] --- --- −0.713 [−1.187, −0.235] --- --- 0.36
y3 +3.525 [+3.171, +3.863] --- −0.439 [−0.842, −0.042] --- --- --- n/a 0.21
M. olivaceus y2 +4.510 [+4.218, +4.805] --- --- --- --- +0.366 [+0.057, +0.682] --- 0.51
y3 +4.601 [+4.318, +4.885] --- --- --- --- +0.346 [+0.048, +0.639] n/a 0.54
  1. Models are listed with formula and Akaike weight (ωi). Coefficient of determination, degrees of freedom and F-ratios are given in the main text. Credible intervals (in square brackets) of all predictor coefficients in these selected models do not overlap zero. This selection criterion was not met by other models within 2 AICc of top-ranked models (see Additional file 1: Table S1). Corticosterone response variables (ng/ml) are log-transformed to base e. Models are given for total and sex-partitioned interspecific corticosterone variation as well as for intraspecific analyses of the wedge-billed woodcreeper (G. spirurus) and olive-striped flycatcher (M. olivaceus). Abbreviated candidate variables are sampling time of day, sampling date, molt status, hemoglobin concentration, relative body mass and sampling latency. Interspecific analyses employ body mass : tarsus ratio as the relative mass variable, whereas intraspecific analyses employ a scaled mass index. a ∆AICc = 0.060 (all other models listed in this table ranked first in AICc analyses)