Do melanin-based tail patterns predict individual quality and sex in Lesser Grey Shrikes Lanius minor?

In many bird species, males display colourful, usually carotenoid or structurally based plumage ornaments. On the other hand, there are many bird species and entire avian genera that are achromatic, i.e. with predominantly white, grey and black plumage colours. Achromatic plumage is a typical feature in many shrikes for example. In this study, we examine the importance of an achromatic plumage pattern, namely, the black tail spots on the two outermost tail feathers (T6 and T5) of Lesser Grey Shrikes (LGS) for sex discrimination and as an indicator of individual quality. Our results suggest that the black tail patterns, especially spots on T5, are important for sex discrimination, but only in combination with other melanin-based or morphological features. The presence of black tail spots on T5 is also an indicator of male age. However, there is no indication that presence, size and asymmetry of these black spots are indicators of individual quality of both sexes in the terms of breeding performances.