Table 2.
Responses to simulated territorial intrusions depended on song’s match to acoustic environment and adrenocortical responsiveness of individuals.
| Number of songs | Number of calls | Number of attacks | Number of wing flicks | Min approach distance | Ln time to min approach | |
|---|---|---|---|---|---|---|
| Song type (adjusted vs. unadjusted) | −1.21 ± 0.95 (0.203) |
6.05 ± 1.69 (<0.001) |
−1.45 ± 0.45 (0.001) | −0.94 ± 0.42 (0.025) | 2.77 ± 2.84 (0.34) |
−0.04 ± 0.25 (0.868) |
| Infrastructure (pumpjack vs. control) | 2.17 ± 0.74 (0.003) | 3.21 ± 2.31 (0.164) | −2.04 ± 0.87 (0.019) | −0.84 ± 0.82 (0.31) | 8.14 ± 3.58 (0.028) | 0.36 ± 0.50 (0.479) |
| Infrastructure (screw pump vs. control) | 1.1 ± 0.75 (0.144) |
5.68 ± 1.97 (0.004) | −0.56 ± 0.71 (0.43) | −0.78 ± 0.73 (0.286) | 2.23 ± 3.23 (0.493) | 0.17 ± 0.48 (0.728) |
| CORT | −0.44 ± 0.83 (0.60) |
9.32 ± 2.52 (<0.001) |
0.70 ± 0.66 (0.292) | 0.08 ± 0.68 (0.904) | 0.7 ± 3.12 (0.824) |
−1.15 ± 0.46 (0.016) |
| Song type x Infrastructure (pumpjack vs. control) | 0.66 ± 0.98 (0.502) | −4.37 ± 2.14 (0.041) |
3.31 ± 0.77 (<0.001) |
1.3 ± 0.85 (0.126) |
−8.72 ± 4.24 (0.05) | −0.06 ± 0.39 (0.875) |
| Song type x Infrastructure (screw pump vs. control) | 1.9 ± 1.01 (0.06) |
−7.02 ± 1.78 (<0.001) |
1.41 ± 0.52 (0.006) | 1.37 ± 0.58 (0.017) | −4.64 ± 4.05 (0.264) | −0.22 ± 0.35 (0.535) |
| Song type x CORT | 3.66 ± 1.34 (0.006) | −9.19 ± 2.59 (<0.001) |
0.93 ± 0.61 (0.13) |
1.23 ± 0.68 (0.072) | −3.78 ± 3.77 (0.328) | 0.12 ± 0.33 (0.73) |
| Infrastructure (pumpjack vs. control) x CORT | 0.58 ± 0.90 (0.515) |
−7.79 ± 2.64 (0.003) | 0.43 ± 0.85 (0.607) | −1.16 ± 0.94 (0.218) | −5.81 ± 3.83 (0.136) | 0.57 ± 0.55 (0.302) |
| Infrastructure (screw pump vs control) x CORT | 1.41 ± 1.01 (0.165) | −9.72 ± 2.65 (<0.001) |
−0.62 ± 0.95 (0.516) | −0.3 ± 0.98 (0.756) | 0.02 ± 4.34 (0.996) | 1.52 ± 0.64 (0.023) |
| Song type x Infrastructure (pumpjack vs. control) x CORT | −4.00 ± 1.36 (0.003) | 9.15 ± 2.71 (0.001) | −1.25 ± 0.72 (0.081) | 1.03 ± 0.96 (0.279) | 6.71 ± 4.56 (0.155) | 0.22 ± 0.41 (0.592) |
| Song type x Infrastructure (screw pump vs. control) x CORT | −4.81 ± 1.45 (0.001) | 8.78 ± 2.82 (0.002) | −1.04 ± 0.7 (0.14) |
−1.93 ± 0.88 (0.028) | 5.57 ± 5.80 (0.346) |
−0.13 ± 0.53 (0.812) |
Results are β ±s.e. (P), P ≤ 0.05 in bold. Categorical variables are shown with 1 vs. 0 (i.e. adjusted = 1 and unadjusted = 0), such that a positive β indicates an increase with category 1.We tested whether adjusted songs received appropriate responses in noisy environments with song played, infrastructure type and adrenocortical responsiveness as fixed effects, plus all interactions, with individual as random effect. Playbacks (n = 57) to individuals (n = 35) were divided by song and infrastructure: unadjusted songs at control sites (reference category; playbacks: n = 10), adjusted songs at control sites (playbacks: n = 9), unadjusted songs at infrastructure sites (playbacks: npumpjacks = 10; nscrew pumps = 9) and adjusted songs at infrastructure sites (playbacks: npumpjacks = 8; nscrew pumps = 11). Categorical variables are shown with 1 vs. 0 (i.e. adjusted = 1 and unadjusted = 0), such that a positive β indicates an increase with category 1.