colour in birds The plumage colour represents one of the most striking features of birds and is also one of the most important signs in visual communication between species and coespecific (Zahavi & Zahavi 1997, Hamilton & Zuk 1998; Rowe & Skelhorn 2004). In birds, colorful plumages are one of the most classic examples of secondary sexual characteristics, especially among species with marked sexual dimorphism, indicating strong sexual selection in this phenotypic trait (Darwin 1958 and Henderson et al 2013). Thus, great discussion on how sexual selection has modeled the colour of birds still seems to lack consensus (Prum 2012) and studies on colour diversity offer great opportunities to understand the origins and maintenance of this diversity (Hill & McGraw 2006). Colorful plumages may represent a high cost to produce and maintain, and some hypotheses based on sexual selection mechanisms have sought to explain the evolution of conspicuity in these traits, especially in polygynic clades (eg quality indicator, Fisher's runaway selection, sensory direction; review in Andersson 1994, Prum 1997, Price 2008). Zahavi & Zahavi (1997) predicts that the female's preference for certain conspicuous characteristics of the male is not random, but may indicate individual genetic quality (Zahavi & Zahavi 1997; Taylor & McGraw 2007). The evolution and maintenance of conspicuous colours would depend on the balance between the partner's choice requirements and the survival costs imposed by natural selection through predation. The development of selected characters in this way would work as an effective quality marker, enabling the ability of one sex to detect quality in the opposite sex selected (Zahavi, 1975, 1977; Grafen, 1990).