Elsevier

Animal Behaviour

Volume 71, Issue 5, May 2006, Pages 1089-1093
Animal Behaviour

Is tail wagging in white wagtails, Motacilla alba, an honest signal of vigilance?

https://doi.org/10.1016/j.anbehav.2005.07.026Get rights and content

The function and adaptive value of tail wagging in many bird species are not yet fully understood. Possible functions are flushing insects, displaying submission and signalling an individual's state of alertness to predators. To distinguish between these, I observed feeding and preening white wagtails in August–September 2004 near Husum, Germany. I counted vigilance events (head-up and left–right scans), tail wags and pecks during feeding. Adults and juveniles did not differ in the frequency of tail wagging. Feeding wagtails wagged more often than preening wagtails and, among feeding wagtails, wagging was positively correlated with scanning and negatively correlated with pecking. In preening wagtails wagging was positively correlated with left–right scans. The prey-flushing hypothesis was partially supported, but seems unlikely since wagging occurred during preening and was negatively correlated with pecking. As wagging did not differ between adults and juveniles it is unlikely to signal submission. It may be an honest signal of vigilance during both feeding and preening; this would explain the negative correlation between wagging and pecking because wagtails adopt a nonvigilant posture during pecking.

Section snippets

Data Collection

The study was carried out in the vicinity of Husum (54°28′N, 09°03′E), Schleswig-Holstein in northern Germany near to the North Sea coast, where large areas are covered by agricultural fields, grassland habitats and salt marshes (totalling approximately 150 km2). I collected data during the postbreeding season between 18 August and 8 September 2004. I visited many sites over 3 weeks and observed and videotaped wagtails. I made observations from a distance where there was no obvious influence on

Results

During feeding, wagtails wagged their tails 0.04–1.78 times/s (X¯±SE = 0.52 ± 0.03, N = 81; untransformed data) and wagging rate differed between individuals in the three plots (plot 1: 0.47 ± 0.08 wags/s, variance 0.10–0.76, N = 8; plot 2: 0.55 ± 0.08 wags/s, variance 0.18–0.92, N = 11; plot 3: 0.47 ± 0.09 wags/s, variance 0.05–1.78, N = 22). Based on the total sample, adult and juvenile wagtails did not differ in tail-wagging frequency during feeding or preening (independent samples t test: preening: t18 = −1.236; P =

Discussion

I found no difference between adults and juveniles in tail wagging but a difference between feeding and preening, both in the matched-pair comparison and in the independent data set. Furthermore, scanning, but not pecking, was positively correlated with wagging.

Acknowledgments

I am grateful to Will Cresswell and an anonymous referee for their comments that significantly improved the manuscript.

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