Ultraviolet vision in a passeriform bird: from receptor spectral sensitivity to overall spectral sensitivity in Leiothrix lutea.

A survey of recent results out of spectrophotometric, microspectrophotometric, and behavioral tests concerning the UV vision of the passeriform bird Leiothrix lutea is presented. In the spectrophotometric study it was shown that the ocular media of Leiothrix' eyes are highly transparent to the near UV with lambda T50 at 320 nm. The comparison of the microspectrophotometric and the behavioral data showed a good fit between the peaks of the four single cones' effective sensitivity spectra and the four peaks in the behavioral spectral sensitivity function. The relation further suggests that the behavioral function might be described as the "over-envelope" of the single cone sensitivities. Leiothrix lutea possesses a genuine UV cone type and reveals it's highest sensitivity in the behavioral test to UV light.