Multiple tests of the effect of nasal saddles on dabbling ducks: combining field and aviary approaches
Résumé
Capsule Nasal saddles have no negative consequences apart from, under some circumstances, a potential bias in social relationships. Aims To test the effect of nasal saddles on Teal Anas crecca, Wigeon A. penelope, Mallard A. platyrhynchos and Pintail A. acuta. Methods The following features were compared between saddled and unsaddled individuals: body mass change of wild Teal between ringing and first live recovery, pairing probability of wild Teal through the winter, wild Teal and Wigeon time-budgets, captive Mallard and Pintail body mass fluctuations, testosterone levels and dominance in the aviary. Results We generally found no significant difference between values for birds with nasal saddles and control birds. Exceptions were for pairing probability, which was lower for marked Teal during one of the winters, and the proportion of aggressive interactions won by Pintail, which decreased after they were fitted with saddles, while this did not happen in Mallard. Conclusions Nasal saddles are an appropriate general method for marking dabbling ducks. However, saddles may not be appropriate for the study of social relationships in some conditions.