Color mixing in the pigeon (Columba livia) II: A psychophysical determination in the middle, short and near-UV wavelength range.
Pigeons were trained to discriminate between spectral lights and additive mixtures in the 350-560 nm spectral range using a successive "autoshaping" discrimination procedure [introduced in Palacios, Martinoya, Bloch & Varela, Vision Research, 30, 587-596 (1990)]. Dichromatic mixtures were found in the short and near UV region, but not in the middle-wave region. Our results suggest that color vision in the pigeon involves the active participation of five different primary mechanisms, which are differentially active in the yellow- and red-sensitive retinal fields.