Birds perceive colour
over wavelengths ranging between 300 nm and 660 nm,
whereas bee vision is in the range 300–550 nm. In the
neotropical forests bird-pollinated flowers have been
shown to have typical median reflectance greater that 585
nm, outside the visual range of bees (Altshuler, 2003).
However it should be noted that bees can perceive (and do
visit) some flowers seen as red by humans, if they have at
least some reflectance in the shorter wavelengths as well
by bees as ultraviolet.