Table 2.
Explanatory models of (a) size-corrected body mass (Scaled Mass Index) and (b) PHA-induced of godwits, selected according to Akaike’s information criterion adjusted for small samples (AICc).
| Model rank | Variables | −2LogL | K | AICc | ΔAICc | w i |
|---|---|---|---|---|---|---|
| (a) Scaled Mass Index | ||||||
| Males (n = 30) | ||||||
| 1 | δ 13 C + date | 299.56 | 4 | 305.56 | 0.00 | 0.14 |
| 2 | δ 13 C | 301.63 | 3 | 305.63 | 0.06 | 0.13 |
| 3 | δ 13 C + BP | 300.40 | 4 | 306.40 | 0.84 | 0.09 |
| 4 | δ 13 C + date + year | 298.54 | 5 | 306.54 | 0.98 | 0.08 |
| 5 | δ 13 C + date + BP | 298.90 | 5 | 306.90 | 1.33 | 0.07 |
| 6 | δ 13 C + date + δ 15 N | 299.27 | 5 | 307.27 | 1.70 | 0.06 |
| 7 | δ 13 C + δ 15 N | 301.40 | 4 | 307.40 | 1.84 | 0.05 |
| 8 | δ 13 C + year | 301.43 | 4 | 307.43 | 1.87 | 0.05 |
| 9 | Null model | 2 | ||||
| Females (n = 28) | ||||||
| 1 | date | 283.21 | 3 | 287.21 | 0.00 | 0.19 |
| 2 | date + δ 13 C | 282.00 | 4 | 288.00 | 0.80 | 0.13 |
| 3 | date + BP | 282.88 | 4 | 288.88 | 1.67 | 0.08 |
| 4 | date + δ 15 N | 282.95 | 4 | 288.95 | 1.74 | 0.08 |
| 5 | date + year | 283.00 | 4 | 289.00 | 1.80 | 0.08 |
| 6 | date + δ 13 C + δ 15 N | 281.12 | 5 | 289.12 | 1.92 | 0.07 |
| 7 | Null model | 2 | ||||
| (b) PHA-immune response | ||||||
| Males (n = 13) | ||||||
| δ 13 C | −28.43 | 3 | −24.43 | 0.00 | 0.27 | |
| δ 13 C + SMI | −30.04 | 4 | −24.04 | 0.39 | 0.23 | |
| δ 13 C + δ 15 N | −28.91 | 4 | −22.91 | 1.52 | 0.13 | |
| δ 13 C + BP | −28.52 | 4 | −22.52 | 1.91 | 0.11 | |
| Null model | ||||||
Only candidate models with ∆AICc < 2 and the null model are ranked according to AICc weights (w i). K: the number of parameters in the model (including intercept and variance); BP: breeding plumage score; date: Julian date. Parameter Akaike weights: (a) Males: δ13C = 0.94, date = 0.53, BP: 0.37, year = 0.36, δ15N = 0.27. Females: date = 0.92, δ13C = 0.40, BP: 0.35, δ15N = 0.31, year = 0.29; (b) Males: δ13C = 1.00, SMI = 0.44, δ15N = 0.30, BP = 0.29.