Summary: Griggio et al. (2010)

Preening behaviour is important for plumage maintenance in birds but has received relatively little attention with respect to the role it plays in influencing plumage colouration. Furthermore, elaborate or colourful plumage is important in female mate choice assessment in birds, but few studies have investigated the costs associated with maintaining this trait in good condition (through preening behaviour). Griggio et al. (2010) investigated whether preening behaviour of captive-bred, wild-type budgerigars, Melopsittacus undulatus, changes plumage reflectance and whether females exercise a choice (in two-choice tests) for males that have higher plumage reflectance (i.e. whether female prefer males that were allowed to preen over those prevented from preening or those who could preen, but had plumage what was UV-blocked by UV-absorbing chemicals). Griggio et al. (2010) found that the plumage of unpreened birds showed lower UV reflectance and females showed a preference for preened males. However, when females were given a choice between unpreened and UV-blocked males, they did not show a preference. Their results show that preening mediates plumage colouration (in the UV range) and can convey honest information about a bird's present condition. Furthermore, females are able to exercise a choice based on the level of UV reflectance.