Table 1.
The effects of estimated fuel load (energy stores), subspecies, and sex on three parameters of immune function in Northern wheatears BKA, microbial killing capacity, HP, haptoglobin-like activity; IgY, total immunoglobulins. Variable statistics are given as in the step prior to removal from the model. The final models are in italic.
| β ± SE | t | P | df | |
|---|---|---|---|---|
| BKA model (n = 115) | ||||
| Fuel load | 1.073 ± 0.382 | 2.81 | 0.006 | 1 |
| Subspecies | 0.197 ± 0.078 | 2.52 | 0.013 | 1 |
| Sex | 0.065 ± 0.076 | 0.86 | 0.39 | 1 |
| Hp model (n = 115) | ||||
| Fuel load | −0.041 ± 0.064 | −0.65 | 0.52 | 1 |
| Subspecies | 0.016 ± 0.013 | 1.27 | 0.21 | 1 |
| Sex | −0.005 ± 0.013 | −0.36 | 0.72 | 1 |
| IgY model (n = 102) | ||||
| Fuel load | 12.20 ± 2.60 | 4.71 | <0.001 | 1 |
| Subspecies | −0.368 ± 0.537 | −0.69 | 0.50 | 1 |
| Sex | 1.668 ± 0.515 | 3.24 | 0.002 | 1 |
Reference categories were oenanthe for subspecies and male for sex.