ULTRAVIOLET PLUMAGE COLORS PREDICT MATE PREFERENCES IN STARLINGS

Avian plumage has long been used to test theories of sexual selection, with humans assessing the colors, However, many birds see in the ultr aviolet (<400 nm), to which humans are blind, Consequently, it is impo rtant to know whether natural variation in UV reflectance from plumage functions in sexual signaling, We show that female starlings rank mal es differently when UV wavelengths are present or absent, Principal co mponent analysis of approximate to 1300 reflectance spectra (300-700 n m) taken from sexually dimorphic plumage regions of males predicted pr eference under the UV+ treatment. Under UV- conditions, females ranked males in a different and nonrandom order, but plumage reflectance in the human visible spectrum did not predict choice, Natural variation i n UV reflectance is thus important in avian mate assessment, and the p revailing light environment can have profound effects on observed mati ng preferences.