COLORED LEG BANDS AFFECT MALE MATE-GUARDING BEHAVIOR IN THE BLUETHROAT

Artificial traits such as coloured leg bands may affect an individual' s mating success, as shown for some birds. One explanation is that col our-matching with a sexual ornament affects the individual's sexual at tractiveness. This study reports a colour-band experiment with free-li ving bluethroats, Luscinia s. svecica, a species where males have a di stinct blue and chestnut throat and upper breast. There was no apparen t difference in pairing success between males with ornament-matching c olour bands (blue and orange) and males with non-ornamental colour ban ds. However, males with ornamental bands guarded their mates less inte nsely and spent more time singing, performing song flights and intrudi ng into neighbours' territories than males with non-ornamental bands. We conclude that colour bands affect the trade-off between mate guardi ng and advertisement behaviour in a way that is consistent with the hy pothesis that bands with ornamental colours improve a male's attractiv eness. The results are in concordance with a previous study of the sam e population, showing that males with experimentally reduced attractiv eness guarded their mates more closely and advertised less for additio nal mates, than non-manipulated males. (C) 1997 The Association for th e Study of Animal Behaviour.