Five things I learned from the article:
1. Birds are sensitive to four or five wavelengths, while we are sensitive to three; we are trichromats and birds are tetrachromats or pentachromats
2.Some species of birds may even be able to see ultraviolet radiation
3.Birds have a higher proportion of cones to rods than humans in their eyes4.
4.Birds also may have double cones, and their photoreceptors may be different than humans'
4.In a bird retina, the fovea, where there are a lot of cones, is in a line rather than a circle, and there may be two fovea
