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Table 3 Influence of the occurrence of eddies, filaments and current speed on heading velocity

From: Influence of oceanographic structures on foraging strategies: Macaroni penguins at Crozet Islands

HV ~ OW category Intercept Presence of eddy P intercept /P variable AIC Null
 M1 – Outward phase 3.57 ± 0.20 −0.14 ± 0.40 <0.0001/NS +1.87
 M2 – Central phase 1.62 ± 0.11 0.12 ± 0.16 <0.0001/NS +3.30
 M3 – Inward phase 3.43 ± 0.25 −0.635 ± 0.29 <0.0001/< 0.05 - 2.14
HV ~ FSLE (>0.1) Intercept FSLE (>0.1) P intercept /P variable AIC Null
 M4 Whole trip 3.60 ± 0.51 −7.29 ± 2.78 <0.001/< 0.05 - 6.40
TV ~ Current speed Intercept Current speed P intercept /P variable AIC Null
 M5 Whole trip 3.51 ± 0.19 −1.51 ± 0.24 <0.001/<0.001 −27.38
  1. Linear mixed models were independently built with individual bird included as a random effect (n = 6) for each explanatory variable. Response variables are heading velocity (HV) and travel velocity (TV). The Okubo-Weiss parameter is a binary factor coding for the occurrence of eddies (0: absence, 1: presence). Current speed and FSLE are continuous variables. Only FSLE values >0.1d−1 were selected to test for the influence of filaments on HV when penguins were within a filament. Significant coefficients (mean ± se) are in bold. P p.value, NS non-significant. AIC Null shows the AIC deviation from AIC of the null model