Figure 1
From: The phylogenetic distribution of ultraviolet sensitivity in birds
Examples of spectral sensitivities for VS and UVS birds. Normalized sensitivities for the single cone classes (from left to right) SWS1, SWS2, MWS and LWS, including the effects of ocular medium absorption. The VS example is the Indian peafowl Pavo cristatus[39] and the UVS is the Eurasian blue tit Cyanistes caeruleus[9]. Human visible range is approximately 400–700 nm; wavelengths below that range are termed ultraviolet