Does beak coloration of male blackbirds play a role in intra and/or intersexual selection?

In many bird species, males may show brightly coloured traits and variance in male mating success may be explained by female preference and/or competition between males favouring the most coloured males. Male beak coloration has been suggested to play an important role in the pairing pattern of European blackbirds. Here, we investigate female preference and male-male interactions in relation to male beak coloration in this species. We used a field experiment to measure female and male responses toward stuffed decoys showing either of two beak coloration representing the extremes of the natural variation from yellow to orange. Decoys were situated on the centre of plots and behaviours of males and females approaching the decoy were recorded. The total number of males and females approaching the decoy did not differ between the two model treatments. Similarly, there was no difference in the mean time that males and females spent near the decoy. The number of males displaying aggressive postures did not differ between treatments and no female adopted a sexual posture. We discuss the relevance of our results and potential limitations associated with the experimental procedure.